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Thomas Gleixner45051532019-05-29 16:57:47 -07001// SPDX-License-Identifier: GPL-2.0-only
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002/*
3 * mm/kmemleak.c
4 *
5 * Copyright (C) 2008 ARM Limited
6 * Written by Catalin Marinas <catalin.marinas@arm.com>
7 *
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01008 * For more information on the algorithm and kmemleak usage, please see
Andreas Platschek22901c62016-12-12 16:42:01 -08009 * Documentation/dev-tools/kmemleak.rst.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010010 *
11 * Notes on locking
12 * ----------------
13 *
14 * The following locks and mutexes are used by kmemleak:
15 *
He Zhe8c96f1b2020-01-30 22:12:00 -080016 * - kmemleak_lock (raw_spinlock_t): protects the object_list modifications and
Patrick Wang0c24e062022-06-11 11:55:50 +080017 * accesses to the object_tree_root (or object_phys_tree_root). The
18 * object_list is the main list holding the metadata (struct kmemleak_object)
19 * for the allocated memory blocks. The object_tree_root and object_phys_tree_root
20 * are red black trees used to look-up metadata based on a pointer to the
21 * corresponding memory block. The object_phys_tree_root is for objects
22 * allocated with physical address. The kmemleak_object structures are
23 * added to the object_list and object_tree_root (or object_phys_tree_root)
24 * in the create_object() function called from the kmemleak_alloc() (or
25 * kmemleak_alloc_phys()) callback and removed in delete_object() called from
26 * the kmemleak_free() callback
He Zhe8c96f1b2020-01-30 22:12:00 -080027 * - kmemleak_object.lock (raw_spinlock_t): protects a kmemleak_object.
28 * Accesses to the metadata (e.g. count) are protected by this lock. Note
29 * that some members of this structure may be protected by other means
30 * (atomic or kmemleak_lock). This lock is also held when scanning the
31 * corresponding memory block to avoid the kernel freeing it via the
32 * kmemleak_free() callback. This is less heavyweight than holding a global
33 * lock like kmemleak_lock during scanning.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010034 * - scan_mutex (mutex): ensures that only one thread may scan the memory for
35 * unreferenced objects at a time. The gray_list contains the objects which
36 * are already referenced or marked as false positives and need to be
37 * scanned. This list is only modified during a scanning episode when the
38 * scan_mutex is held. At the end of a scan, the gray_list is always empty.
39 * Note that the kmemleak_object.use_count is incremented when an object is
Catalin Marinas4698c1f2009-06-26 17:38:27 +010040 * added to the gray_list and therefore cannot be freed. This mutex also
41 * prevents multiple users of the "kmemleak" debugfs file together with
42 * modifications to the memory scanning parameters including the scan_thread
43 * pointer
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010044 *
Catalin Marinas93ada572015-06-24 16:58:37 -070045 * Locks and mutexes are acquired/nested in the following order:
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070046 *
Catalin Marinas93ada572015-06-24 16:58:37 -070047 * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING)
48 *
49 * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex
50 * regions.
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070051 *
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010052 * The kmemleak_object structures have a use_count incremented or decremented
53 * using the get_object()/put_object() functions. When the use_count becomes
54 * 0, this count can no longer be incremented and put_object() schedules the
55 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
56 * function must be protected by rcu_read_lock() to avoid accessing a freed
57 * structure.
58 */
59
Joe Perchesae281062009-06-23 14:40:26 +010060#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
61
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010062#include <linux/init.h>
63#include <linux/kernel.h>
64#include <linux/list.h>
Ingo Molnar3f07c012017-02-08 18:51:30 +010065#include <linux/sched/signal.h>
Ingo Molnar29930022017-02-08 18:51:36 +010066#include <linux/sched/task.h>
Ingo Molnar68db0cf2017-02-08 18:51:37 +010067#include <linux/sched/task_stack.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010068#include <linux/jiffies.h>
69#include <linux/delay.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040070#include <linux/export.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010071#include <linux/kthread.h>
Michel Lespinasse85d3a312012-10-08 16:31:27 -070072#include <linux/rbtree.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010073#include <linux/fs.h>
74#include <linux/debugfs.h>
75#include <linux/seq_file.h>
76#include <linux/cpumask.h>
77#include <linux/spinlock.h>
Vincent Whitchurch154221c2018-10-26 15:03:42 -070078#include <linux/module.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010079#include <linux/mutex.h>
80#include <linux/rcupdate.h>
81#include <linux/stacktrace.h>
82#include <linux/cache.h>
83#include <linux/percpu.h>
Mike Rapoport57c8a662018-10-30 15:09:49 -070084#include <linux/memblock.h>
Catalin Marinas9099dae2016-10-11 13:55:11 -070085#include <linux/pfn.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010086#include <linux/mmzone.h>
87#include <linux/slab.h>
88#include <linux/thread_info.h>
89#include <linux/err.h>
90#include <linux/uaccess.h>
91#include <linux/string.h>
92#include <linux/nodemask.h>
93#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +010094#include <linux/workqueue.h>
Catalin Marinas04609ccc2009-10-28 13:33:12 +000095#include <linux/crc32.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010096
97#include <asm/sections.h>
98#include <asm/processor.h>
Arun Sharma600634972011-07-26 16:09:06 -070099#include <linux/atomic.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100100
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -0800101#include <linux/kasan.h>
Marco Elver95511582021-03-24 21:37:47 -0700102#include <linux/kfence.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100103#include <linux/kmemleak.h>
Laura Abbott029aeff2011-11-15 23:49:09 +0000104#include <linux/memory_hotplug.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100105
106/*
107 * Kmemleak configuration and common defines.
108 */
109#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100110#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100111#define SECS_FIRST_SCAN 60 /* delay before the first scan */
112#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinasaf986032009-08-27 14:29:12 +0100113#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100114
115#define BYTES_PER_POINTER sizeof(void *)
116
Catalin Marinas216c04b2009-06-17 18:29:02 +0100117/* GFP bitmask for kmemleak internal allocations */
Naohiro Aota79d37052021-09-08 18:10:17 -0700118#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC | \
119 __GFP_NOLOCKDEP)) | \
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000120 __GFP_NORETRY | __GFP_NOMEMALLOC | \
Yang Shidf9576d2019-08-02 21:48:37 -0700121 __GFP_NOWARN)
Catalin Marinas216c04b2009-06-17 18:29:02 +0100122
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100123/* scanning area inside a memory block */
124struct kmemleak_scan_area {
125 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000126 unsigned long start;
127 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100128};
129
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700130#define KMEMLEAK_GREY 0
131#define KMEMLEAK_BLACK -1
132
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100133/*
134 * Structure holding the metadata for each allocated memory block.
135 * Modifications to such objects should be made while holding the
136 * object->lock. Insertions or deletions from object_list, gray_list or
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700137 * rb_node are already protected by the corresponding locks or mutex (see
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100138 * the notes on locking above). These objects are reference-counted
139 * (use_count) and freed using the RCU mechanism.
140 */
141struct kmemleak_object {
He Zhe8c96f1b2020-01-30 22:12:00 -0800142 raw_spinlock_t lock;
Catalin Marinasf66abf02017-07-06 15:40:16 -0700143 unsigned int flags; /* object status flags */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100144 struct list_head object_list;
145 struct list_head gray_list;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700146 struct rb_node rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100147 struct rcu_head rcu; /* object_list lockless traversal */
148 /* object usage count; object freed when use_count == 0 */
149 atomic_t use_count;
150 unsigned long pointer;
151 size_t size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700152 /* pass surplus references to this pointer */
153 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100154 /* minimum number of a pointers found before it is considered leak */
155 int min_count;
156 /* the total number of pointers found pointing to this object */
157 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000158 /* checksum for detecting modified objects */
159 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100160 /* memory ranges to be scanned inside an object (empty for all) */
161 struct hlist_head area_list;
162 unsigned long trace[MAX_TRACE];
163 unsigned int trace_len;
164 unsigned long jiffies; /* creation timestamp */
165 pid_t pid; /* pid of the current task */
166 char comm[TASK_COMM_LEN]; /* executable name */
167};
168
169/* flag representing the memory block allocation status */
170#define OBJECT_ALLOCATED (1 << 0)
171/* flag set after the first reporting of an unreference object */
172#define OBJECT_REPORTED (1 << 1)
173/* flag set to not scan the object */
174#define OBJECT_NO_SCAN (1 << 2)
Catalin Marinasdba82d92019-09-23 15:33:59 -0700175/* flag set to fully scan the object when scan_area allocation failed */
176#define OBJECT_FULL_SCAN (1 << 3)
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800177/* flag set for object allocated with physical address */
178#define OBJECT_PHYS (1 << 4)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100179
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700180#define HEX_PREFIX " "
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100181/* number of bytes to print per line; must be 16 or 32 */
182#define HEX_ROW_SIZE 16
183/* number of bytes to print at a time (1, 2, 4, 8) */
184#define HEX_GROUP_SIZE 1
185/* include ASCII after the hex output */
186#define HEX_ASCII 1
187/* max number of lines to be printed */
188#define HEX_MAX_LINES 2
189
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100190/* the list of all allocated objects */
191static LIST_HEAD(object_list);
192/* the list of gray-colored objects (see color_gray comment below) */
193static LIST_HEAD(gray_list);
Catalin Marinas06473982019-09-23 15:34:02 -0700194/* memory pool allocation */
Catalin Marinasc5665862019-09-23 15:34:05 -0700195static struct kmemleak_object mem_pool[CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE];
Catalin Marinas06473982019-09-23 15:34:02 -0700196static int mem_pool_free_count = ARRAY_SIZE(mem_pool);
197static LIST_HEAD(mem_pool_free_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700198/* search tree for object boundaries */
199static struct rb_root object_tree_root = RB_ROOT;
Patrick Wang0c24e062022-06-11 11:55:50 +0800200/* search tree for object (with OBJECT_PHYS flag) boundaries */
201static struct rb_root object_phys_tree_root = RB_ROOT;
202/* protecting the access to object_list, object_tree_root (or object_phys_tree_root) */
He Zhe8c96f1b2020-01-30 22:12:00 -0800203static DEFINE_RAW_SPINLOCK(kmemleak_lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100204
205/* allocation caches for kmemleak internal data */
206static struct kmem_cache *object_cache;
207static struct kmem_cache *scan_area_cache;
208
209/* set if tracing memory operations is enabled */
Catalin Marinasc5665862019-09-23 15:34:05 -0700210static int kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700211/* same as above but only for the kmemleak_free() callback */
Catalin Marinasc5665862019-09-23 15:34:05 -0700212static int kmemleak_free_enabled = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100213/* set in the late_initcall if there were no errors */
Li Zefan8910ae892014-04-03 14:46:29 -0700214static int kmemleak_initialized;
Catalin Marinas5f790202011-09-28 12:17:03 +0100215/* set if a kmemleak warning was issued */
Li Zefan8910ae892014-04-03 14:46:29 -0700216static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100217/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae892014-04-03 14:46:29 -0700218static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100219
220/* minimum and maximum address that may be valid pointers */
221static unsigned long min_addr = ULONG_MAX;
222static unsigned long max_addr;
223
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100224static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100225/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100226static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100227static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100228/* delay between automatic memory scannings */
Yanfei Xu54dd2002021-06-28 19:35:01 -0700229static unsigned long jiffies_scan_wait;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100230/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100231static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100232/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100233static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100234/* setting kmemleak=on, will set this var, skipping the disable */
235static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700236/* If there are leaks that can be reported */
237static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100238
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700239static bool kmemleak_verbose;
240module_param_named(verbose, kmemleak_verbose, bool, 0600);
241
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100242static void kmemleak_disable(void);
243
244/*
245 * Print a warning and dump the stack trace.
246 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100247#define kmemleak_warn(x...) do { \
Joe Perches598d8092016-03-17 14:19:44 -0700248 pr_warn(x); \
Catalin Marinas5f790202011-09-28 12:17:03 +0100249 dump_stack(); \
Li Zefan8910ae892014-04-03 14:46:29 -0700250 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100251} while (0)
252
253/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300254 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100255 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100256 * tracing no longer available.
257 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100258#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100259 kmemleak_warn(x); \
260 kmemleak_disable(); \
261} while (0)
262
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700263#define warn_or_seq_printf(seq, fmt, ...) do { \
264 if (seq) \
265 seq_printf(seq, fmt, ##__VA_ARGS__); \
266 else \
267 pr_warn(fmt, ##__VA_ARGS__); \
268} while (0)
269
270static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type,
271 int rowsize, int groupsize, const void *buf,
272 size_t len, bool ascii)
273{
274 if (seq)
275 seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize,
276 buf, len, ascii);
277 else
278 print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type,
279 rowsize, groupsize, buf, len, ascii);
280}
281
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100282/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100283 * Printing of the objects hex dump to the seq file. The number of lines to be
284 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
285 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
286 * with the object->lock held.
287 */
288static void hex_dump_object(struct seq_file *seq,
289 struct kmemleak_object *object)
290{
291 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700292 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100293
Patrick Wang0c24e062022-06-11 11:55:50 +0800294 if (WARN_ON_ONCE(object->flags & OBJECT_PHYS))
295 return;
296
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100297 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700298 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100299
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700300 warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700301 kasan_disable_current();
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700302 warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE,
Kuan-Ying Lee6c7a00b2021-08-13 16:54:24 -0700303 HEX_GROUP_SIZE, kasan_reset_tag((void *)ptr), len, HEX_ASCII);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700304 kasan_enable_current();
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100305}
306
307/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100308 * Object colors, encoded with count and min_count:
309 * - white - orphan object, not enough references to it (count < min_count)
310 * - gray - not orphan, not marked as false positive (min_count == 0) or
311 * sufficient references to it (count >= min_count)
312 * - black - ignore, it doesn't contain references (e.g. text section)
313 * (min_count == -1). No function defined for this color.
314 * Newly created objects don't have any color assigned (object->count == -1)
315 * before the next memory scan when they become white.
316 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100317static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100318{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700319 return object->count != KMEMLEAK_BLACK &&
320 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100321}
322
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100323static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100324{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700325 return object->min_count != KMEMLEAK_BLACK &&
326 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100327}
328
329/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100330 * Objects are considered unreferenced only if their color is white, they have
331 * not be deleted and have a minimum age to avoid false positives caused by
332 * pointers temporarily stored in CPU registers.
333 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100334static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100335{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000336 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100337 time_before_eq(object->jiffies + jiffies_min_age,
338 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100339}
340
341/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100342 * Printing of the unreferenced objects information to the seq file. The
343 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100344 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100345static void print_unreferenced(struct seq_file *seq,
346 struct kmemleak_object *object)
347{
348 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000349 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100350
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700351 warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
Catalin Marinasbab4a342009-06-26 17:38:26 +0100352 object->pointer, object->size);
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700353 warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
Catalin Marinasfefdd332009-10-28 13:33:12 +0000354 object->comm, object->pid, object->jiffies,
355 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100356 hex_dump_object(seq, object);
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700357 warn_or_seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100358
359 for (i = 0; i < object->trace_len; i++) {
360 void *ptr = (void *)object->trace[i];
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700361 warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100362 }
363}
364
365/*
366 * Print the kmemleak_object information. This function is used mainly for
367 * debugging special cases when kmemleak operations. It must be called with
368 * the object->lock held.
369 */
370static void dump_object_info(struct kmemleak_object *object)
371{
Joe Perchesae281062009-06-23 14:40:26 +0100372 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700373 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100374 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
375 object->comm, object->pid, object->jiffies);
376 pr_notice(" min_count = %d\n", object->min_count);
377 pr_notice(" count = %d\n", object->count);
Catalin Marinasf66abf02017-07-06 15:40:16 -0700378 pr_notice(" flags = 0x%x\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700379 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100380 pr_notice(" backtrace:\n");
Thomas Gleixner07984aa2019-04-25 11:45:01 +0200381 stack_trace_print(object->trace, object->trace_len, 4);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100382}
383
384/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700385 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100386 * tree based on a pointer value. If alias is 0, only values pointing to the
387 * beginning of the memory block are allowed. The kmemleak_lock must be held
388 * when calling this function.
389 */
Patrick Wang0c24e062022-06-11 11:55:50 +0800390static struct kmemleak_object *__lookup_object(unsigned long ptr, int alias,
391 bool is_phys)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100392{
Patrick Wang0c24e062022-06-11 11:55:50 +0800393 struct rb_node *rb = is_phys ? object_phys_tree_root.rb_node :
394 object_tree_root.rb_node;
Kuan-Ying Leead1a3e12022-01-14 14:04:04 -0800395 unsigned long untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100396
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700397 while (rb) {
Kuan-Ying Leead1a3e12022-01-14 14:04:04 -0800398 struct kmemleak_object *object;
399 unsigned long untagged_objp;
400
401 object = rb_entry(rb, struct kmemleak_object, rb_node);
402 untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer);
403
404 if (untagged_ptr < untagged_objp)
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700405 rb = object->rb_node.rb_left;
Kuan-Ying Leead1a3e12022-01-14 14:04:04 -0800406 else if (untagged_objp + object->size <= untagged_ptr)
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700407 rb = object->rb_node.rb_right;
Kuan-Ying Leead1a3e12022-01-14 14:04:04 -0800408 else if (untagged_objp == untagged_ptr || alias)
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700409 return object;
410 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100411 kmemleak_warn("Found object by alias at 0x%08lx\n",
412 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100413 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700414 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100415 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700416 }
417 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100418}
419
Patrick Wang0c24e062022-06-11 11:55:50 +0800420/* Look-up a kmemleak object which allocated with virtual address. */
421static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
422{
423 return __lookup_object(ptr, alias, false);
424}
425
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100426/*
427 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
428 * that once an object's use_count reached 0, the RCU freeing was already
429 * registered and the object should no longer be used. This function must be
430 * called under the protection of rcu_read_lock().
431 */
432static int get_object(struct kmemleak_object *object)
433{
434 return atomic_inc_not_zero(&object->use_count);
435}
436
437/*
Catalin Marinas06473982019-09-23 15:34:02 -0700438 * Memory pool allocation and freeing. kmemleak_lock must not be held.
439 */
440static struct kmemleak_object *mem_pool_alloc(gfp_t gfp)
441{
442 unsigned long flags;
443 struct kmemleak_object *object;
444
445 /* try the slab allocator first */
Catalin Marinasc5665862019-09-23 15:34:05 -0700446 if (object_cache) {
447 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
448 if (object)
449 return object;
450 }
Catalin Marinas06473982019-09-23 15:34:02 -0700451
452 /* slab allocation failed, try the memory pool */
He Zhe8c96f1b2020-01-30 22:12:00 -0800453 raw_spin_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas06473982019-09-23 15:34:02 -0700454 object = list_first_entry_or_null(&mem_pool_free_list,
455 typeof(*object), object_list);
456 if (object)
457 list_del(&object->object_list);
458 else if (mem_pool_free_count)
459 object = &mem_pool[--mem_pool_free_count];
Catalin Marinasc5665862019-09-23 15:34:05 -0700460 else
461 pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n");
He Zhe8c96f1b2020-01-30 22:12:00 -0800462 raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinas06473982019-09-23 15:34:02 -0700463
464 return object;
465}
466
467/*
468 * Return the object to either the slab allocator or the memory pool.
469 */
470static void mem_pool_free(struct kmemleak_object *object)
471{
472 unsigned long flags;
473
474 if (object < mem_pool || object >= mem_pool + ARRAY_SIZE(mem_pool)) {
475 kmem_cache_free(object_cache, object);
476 return;
477 }
478
479 /* add the object to the memory pool free list */
He Zhe8c96f1b2020-01-30 22:12:00 -0800480 raw_spin_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas06473982019-09-23 15:34:02 -0700481 list_add(&object->object_list, &mem_pool_free_list);
He Zhe8c96f1b2020-01-30 22:12:00 -0800482 raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinas06473982019-09-23 15:34:02 -0700483}
484
485/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100486 * RCU callback to free a kmemleak_object.
487 */
488static void free_object_rcu(struct rcu_head *rcu)
489{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800490 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100491 struct kmemleak_scan_area *area;
492 struct kmemleak_object *object =
493 container_of(rcu, struct kmemleak_object, rcu);
494
495 /*
496 * Once use_count is 0 (guaranteed by put_object), there is no other
497 * code accessing this object, hence no need for locking.
498 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800499 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
500 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100501 kmem_cache_free(scan_area_cache, area);
502 }
Catalin Marinas06473982019-09-23 15:34:02 -0700503 mem_pool_free(object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100504}
505
506/*
507 * Decrement the object use_count. Once the count is 0, free the object using
508 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
509 * delete_object() path, the delayed RCU freeing ensures that there is no
510 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
511 * is also possible.
512 */
513static void put_object(struct kmemleak_object *object)
514{
515 if (!atomic_dec_and_test(&object->use_count))
516 return;
517
518 /* should only get here after delete_object was called */
519 WARN_ON(object->flags & OBJECT_ALLOCATED);
520
Catalin Marinasc5665862019-09-23 15:34:05 -0700521 /*
522 * It may be too early for the RCU callbacks, however, there is no
523 * concurrent object_list traversal when !object_cache and all objects
524 * came from the memory pool. Free the object directly.
525 */
526 if (object_cache)
527 call_rcu(&object->rcu, free_object_rcu);
528 else
529 free_object_rcu(&object->rcu);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100530}
531
532/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700533 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100534 */
Patrick Wang0c24e062022-06-11 11:55:50 +0800535static struct kmemleak_object *__find_and_get_object(unsigned long ptr, int alias,
536 bool is_phys)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100537{
538 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800539 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100540
541 rcu_read_lock();
He Zhe8c96f1b2020-01-30 22:12:00 -0800542 raw_spin_lock_irqsave(&kmemleak_lock, flags);
Patrick Wang0c24e062022-06-11 11:55:50 +0800543 object = __lookup_object(ptr, alias, is_phys);
He Zhe8c96f1b2020-01-30 22:12:00 -0800544 raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100545
546 /* check whether the object is still available */
547 if (object && !get_object(object))
548 object = NULL;
549 rcu_read_unlock();
550
551 return object;
552}
553
Patrick Wang0c24e062022-06-11 11:55:50 +0800554/* Look up and get an object which allocated with virtual address. */
555static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
556{
557 return __find_and_get_object(ptr, alias, false);
558}
559
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100560/*
Patrick Wang0c24e062022-06-11 11:55:50 +0800561 * Remove an object from the object_tree_root (or object_phys_tree_root)
562 * and object_list. Must be called with the kmemleak_lock held _if_ kmemleak
563 * is still enabled.
Catalin Marinas2abd8392019-10-04 14:46:24 +0100564 */
565static void __remove_object(struct kmemleak_object *object)
566{
Patrick Wang0c24e062022-06-11 11:55:50 +0800567 rb_erase(&object->rb_node, object->flags & OBJECT_PHYS ?
568 &object_phys_tree_root :
569 &object_tree_root);
Catalin Marinas2abd8392019-10-04 14:46:24 +0100570 list_del_rcu(&object->object_list);
571}
572
573/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700574 * Look up an object in the object search tree and remove it from both
Patrick Wang0c24e062022-06-11 11:55:50 +0800575 * object_tree_root (or object_phys_tree_root) and object_list. The
576 * returned object's use_count should be at least 1, as initially set
577 * by create_object().
Catalin Marinase781a9a2015-06-24 16:58:29 -0700578 */
Patrick Wang0c24e062022-06-11 11:55:50 +0800579static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias,
580 bool is_phys)
Catalin Marinase781a9a2015-06-24 16:58:29 -0700581{
582 unsigned long flags;
583 struct kmemleak_object *object;
584
He Zhe8c96f1b2020-01-30 22:12:00 -0800585 raw_spin_lock_irqsave(&kmemleak_lock, flags);
Patrick Wang0c24e062022-06-11 11:55:50 +0800586 object = __lookup_object(ptr, alias, is_phys);
Catalin Marinas2abd8392019-10-04 14:46:24 +0100587 if (object)
588 __remove_object(object);
He Zhe8c96f1b2020-01-30 22:12:00 -0800589 raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinase781a9a2015-06-24 16:58:29 -0700590
591 return object;
592}
593
594/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100595 * Save stack trace to the given array of MAX_TRACE size.
596 */
597static int __save_stack_trace(unsigned long *trace)
598{
Thomas Gleixner07984aa2019-04-25 11:45:01 +0200599 return stack_trace_save(trace, MAX_TRACE, 2);
Catalin Marinasfd678962009-08-27 14:29:17 +0100600}
601
602/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100603 * Create the metadata (struct kmemleak_object) corresponding to an allocated
Patrick Wang0c24e062022-06-11 11:55:50 +0800604 * memory block and add it to the object_list and object_tree_root (or
605 * object_phys_tree_root).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100606 */
Liu Shixinb955aa72022-09-01 10:30:07 +0800607static void __create_object(unsigned long ptr, size_t size,
608 int min_count, gfp_t gfp, bool is_phys)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100609{
610 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700611 struct kmemleak_object *object, *parent;
612 struct rb_node **link, *rb_parent;
Andrey Konovalova2f77572019-02-20 22:19:16 -0800613 unsigned long untagged_ptr;
Kuan-Ying Leead1a3e12022-01-14 14:04:04 -0800614 unsigned long untagged_objp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100615
Catalin Marinas06473982019-09-23 15:34:02 -0700616 object = mem_pool_alloc(gfp);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100617 if (!object) {
Joe Perches598d8092016-03-17 14:19:44 -0700618 pr_warn("Cannot allocate a kmemleak_object structure\n");
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000619 kmemleak_disable();
Liu Shixinb955aa72022-09-01 10:30:07 +0800620 return;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100621 }
622
623 INIT_LIST_HEAD(&object->object_list);
624 INIT_LIST_HEAD(&object->gray_list);
625 INIT_HLIST_HEAD(&object->area_list);
He Zhe8c96f1b2020-01-30 22:12:00 -0800626 raw_spin_lock_init(&object->lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100627 atomic_set(&object->use_count, 1);
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800628 object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100629 object->pointer = ptr;
Marco Elver95511582021-03-24 21:37:47 -0700630 object->size = kfence_ksize((void *)ptr) ?: size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700631 object->excess_ref = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100632 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000633 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100634 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000635 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100636
637 /* task information */
Changbin Duea0eafe2021-09-07 19:56:12 -0700638 if (in_hardirq()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100639 object->pid = 0;
640 strncpy(object->comm, "hardirq", sizeof(object->comm));
Dmitry Vyukov6ef90562019-07-11 20:53:39 -0700641 } else if (in_serving_softirq()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100642 object->pid = 0;
643 strncpy(object->comm, "softirq", sizeof(object->comm));
644 } else {
645 object->pid = current->pid;
646 /*
647 * There is a small chance of a race with set_task_comm(),
648 * however using get_task_comm() here may cause locking
649 * dependency issues with current->alloc_lock. In the worst
650 * case, the command line is not correct.
651 */
652 strncpy(object->comm, current->comm, sizeof(object->comm));
653 }
654
655 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100656 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100657
He Zhe8c96f1b2020-01-30 22:12:00 -0800658 raw_spin_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100659
Andrey Konovalova2f77572019-02-20 22:19:16 -0800660 untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
Patrick Wang0c24e062022-06-11 11:55:50 +0800661 /*
662 * Only update min_addr and max_addr with object
663 * storing virtual address.
664 */
665 if (!is_phys) {
666 min_addr = min(min_addr, untagged_ptr);
667 max_addr = max(max_addr, untagged_ptr + size);
668 }
669 link = is_phys ? &object_phys_tree_root.rb_node :
670 &object_tree_root.rb_node;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700671 rb_parent = NULL;
672 while (*link) {
673 rb_parent = *link;
674 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
Kuan-Ying Leead1a3e12022-01-14 14:04:04 -0800675 untagged_objp = (unsigned long)kasan_reset_tag((void *)parent->pointer);
676 if (untagged_ptr + size <= untagged_objp)
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700677 link = &parent->rb_node.rb_left;
Kuan-Ying Leead1a3e12022-01-14 14:04:04 -0800678 else if (untagged_objp + parent->size <= untagged_ptr)
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700679 link = &parent->rb_node.rb_right;
680 else {
Joe Perches756a0252016-03-17 14:19:47 -0700681 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700682 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700683 /*
684 * No need for parent->lock here since "parent" cannot
685 * be freed while the kmemleak_lock is held.
686 */
687 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700688 kmem_cache_free(object_cache, object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700689 goto out;
690 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100691 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700692 rb_link_node(&object->rb_node, rb_parent, link);
Patrick Wang0c24e062022-06-11 11:55:50 +0800693 rb_insert_color(&object->rb_node, is_phys ? &object_phys_tree_root :
694 &object_tree_root);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700695
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100696 list_add_tail_rcu(&object->object_list, &object_list);
697out:
He Zhe8c96f1b2020-01-30 22:12:00 -0800698 raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100699}
700
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800701/* Create kmemleak object which allocated with virtual address. */
Liu Shixinb955aa72022-09-01 10:30:07 +0800702static void create_object(unsigned long ptr, size_t size,
703 int min_count, gfp_t gfp)
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800704{
Liu Shixinb955aa72022-09-01 10:30:07 +0800705 __create_object(ptr, size, min_count, gfp, false);
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800706}
707
708/* Create kmemleak object which allocated with physical address. */
Liu Shixinb955aa72022-09-01 10:30:07 +0800709static void create_object_phys(unsigned long ptr, size_t size,
710 int min_count, gfp_t gfp)
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800711{
Liu Shixinb955aa72022-09-01 10:30:07 +0800712 __create_object(ptr, size, min_count, gfp, true);
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800713}
714
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100715/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700716 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100717 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100718static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100719{
720 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100721
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100722 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700723 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100724
725 /*
726 * Locking here also ensures that the corresponding memory block
727 * cannot be freed when it is being scanned.
728 */
He Zhe8c96f1b2020-01-30 22:12:00 -0800729 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100730 object->flags &= ~OBJECT_ALLOCATED;
He Zhe8c96f1b2020-01-30 22:12:00 -0800731 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100732 put_object(object);
733}
734
735/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100736 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
737 * delete it.
738 */
739static void delete_object_full(unsigned long ptr)
740{
741 struct kmemleak_object *object;
742
Patrick Wang0c24e062022-06-11 11:55:50 +0800743 object = find_and_remove_object(ptr, 0, false);
Catalin Marinas53238a62009-07-07 10:33:00 +0100744 if (!object) {
745#ifdef DEBUG
746 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
747 ptr);
748#endif
749 return;
750 }
751 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100752}
753
754/*
755 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
756 * delete it. If the memory block is partially freed, the function may create
757 * additional metadata for the remaining parts of the block.
758 */
Patrick Wang0c24e062022-06-11 11:55:50 +0800759static void delete_object_part(unsigned long ptr, size_t size, bool is_phys)
Catalin Marinas53238a62009-07-07 10:33:00 +0100760{
761 struct kmemleak_object *object;
762 unsigned long start, end;
763
Patrick Wang0c24e062022-06-11 11:55:50 +0800764 object = find_and_remove_object(ptr, 1, is_phys);
Catalin Marinas53238a62009-07-07 10:33:00 +0100765 if (!object) {
766#ifdef DEBUG
Joe Perches756a0252016-03-17 14:19:47 -0700767 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
768 ptr, size);
Catalin Marinas53238a62009-07-07 10:33:00 +0100769#endif
770 return;
771 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100772
773 /*
774 * Create one or two objects that may result from the memory block
775 * split. Note that partial freeing is only done by free_bootmem() and
Catalin Marinasc5665862019-09-23 15:34:05 -0700776 * this happens before kmemleak_init() is called.
Catalin Marinas53238a62009-07-07 10:33:00 +0100777 */
778 start = object->pointer;
779 end = object->pointer + object->size;
780 if (ptr > start)
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800781 __create_object(start, ptr - start, object->min_count,
Patrick Wang0c24e062022-06-11 11:55:50 +0800782 GFP_KERNEL, is_phys);
Catalin Marinas53238a62009-07-07 10:33:00 +0100783 if (ptr + size < end)
Patrick Wang8e0c4ab2022-06-11 11:55:49 +0800784 __create_object(ptr + size, end - ptr - size, object->min_count,
Patrick Wang0c24e062022-06-11 11:55:50 +0800785 GFP_KERNEL, is_phys);
Catalin Marinas53238a62009-07-07 10:33:00 +0100786
Catalin Marinase781a9a2015-06-24 16:58:29 -0700787 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100788}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700789
790static void __paint_it(struct kmemleak_object *object, int color)
791{
792 object->min_count = color;
793 if (color == KMEMLEAK_BLACK)
794 object->flags |= OBJECT_NO_SCAN;
795}
796
797static void paint_it(struct kmemleak_object *object, int color)
798{
799 unsigned long flags;
800
He Zhe8c96f1b2020-01-30 22:12:00 -0800801 raw_spin_lock_irqsave(&object->lock, flags);
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700802 __paint_it(object, color);
He Zhe8c96f1b2020-01-30 22:12:00 -0800803 raw_spin_unlock_irqrestore(&object->lock, flags);
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700804}
805
Patrick Wang0c24e062022-06-11 11:55:50 +0800806static void paint_ptr(unsigned long ptr, int color, bool is_phys)
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700807{
808 struct kmemleak_object *object;
809
Patrick Wang0c24e062022-06-11 11:55:50 +0800810 object = __find_and_get_object(ptr, 0, is_phys);
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700811 if (!object) {
Joe Perches756a0252016-03-17 14:19:47 -0700812 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
813 ptr,
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700814 (color == KMEMLEAK_GREY) ? "Grey" :
815 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
816 return;
817 }
818 paint_it(object, color);
819 put_object(object);
820}
821
Catalin Marinas53238a62009-07-07 10:33:00 +0100822/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800823 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100824 * reported as a leak. This is used in general to mark a false positive.
825 */
826static void make_gray_object(unsigned long ptr)
827{
Patrick Wang0c24e062022-06-11 11:55:50 +0800828 paint_ptr(ptr, KMEMLEAK_GREY, false);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100829}
830
831/*
832 * Mark the object as black-colored so that it is ignored from scans and
833 * reporting.
834 */
Patrick Wang0c24e062022-06-11 11:55:50 +0800835static void make_black_object(unsigned long ptr, bool is_phys)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100836{
Patrick Wang0c24e062022-06-11 11:55:50 +0800837 paint_ptr(ptr, KMEMLEAK_BLACK, is_phys);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100838}
839
840/*
841 * Add a scanning area to the object. If at least one such area is added,
842 * kmemleak will only scan these ranges rather than the whole memory block.
843 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000844static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100845{
846 unsigned long flags;
847 struct kmemleak_object *object;
Catalin Marinasc5665862019-09-23 15:34:05 -0700848 struct kmemleak_scan_area *area = NULL;
Kuan-Ying Leebfc80892022-04-01 11:28:54 -0700849 unsigned long untagged_ptr;
850 unsigned long untagged_objp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100851
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000852 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100853 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100854 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
855 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100856 return;
857 }
858
Kuan-Ying Leebfc80892022-04-01 11:28:54 -0700859 untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
860 untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer);
861
Catalin Marinasc5665862019-09-23 15:34:05 -0700862 if (scan_area_cache)
863 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100864
He Zhe8c96f1b2020-01-30 22:12:00 -0800865 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinasdba82d92019-09-23 15:33:59 -0700866 if (!area) {
867 pr_warn_once("Cannot allocate a scan area, scanning the full object\n");
868 /* mark the object for full scan to avoid false positives */
869 object->flags |= OBJECT_FULL_SCAN;
870 goto out_unlock;
871 }
Catalin Marinas7f88f882013-11-12 15:07:45 -0800872 if (size == SIZE_MAX) {
Kuan-Ying Leebfc80892022-04-01 11:28:54 -0700873 size = untagged_objp + object->size - untagged_ptr;
874 } else if (untagged_ptr + size > untagged_objp + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100875 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100876 dump_object_info(object);
877 kmem_cache_free(scan_area_cache, area);
878 goto out_unlock;
879 }
880
881 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000882 area->start = ptr;
883 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100884
885 hlist_add_head(&area->node, &object->area_list);
886out_unlock:
He Zhe8c96f1b2020-01-30 22:12:00 -0800887 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100888 put_object(object);
889}
890
891/*
Catalin Marinas94f4a162017-07-06 15:40:22 -0700892 * Any surplus references (object already gray) to 'ptr' are passed to
893 * 'excess_ref'. This is used in the vmalloc() case where a pointer to
894 * vm_struct may be used as an alternative reference to the vmalloc'ed object
895 * (see free_thread_stack()).
896 */
897static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
898{
899 unsigned long flags;
900 struct kmemleak_object *object;
901
902 object = find_and_get_object(ptr, 0);
903 if (!object) {
904 kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
905 ptr);
906 return;
907 }
908
He Zhe8c96f1b2020-01-30 22:12:00 -0800909 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinas94f4a162017-07-06 15:40:22 -0700910 object->excess_ref = excess_ref;
He Zhe8c96f1b2020-01-30 22:12:00 -0800911 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas94f4a162017-07-06 15:40:22 -0700912 put_object(object);
913}
914
915/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100916 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
917 * pointer. Such object will not be scanned by kmemleak but references to it
918 * are searched.
919 */
920static void object_no_scan(unsigned long ptr)
921{
922 unsigned long flags;
923 struct kmemleak_object *object;
924
925 object = find_and_get_object(ptr, 0);
926 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100927 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100928 return;
929 }
930
He Zhe8c96f1b2020-01-30 22:12:00 -0800931 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100932 object->flags |= OBJECT_NO_SCAN;
He Zhe8c96f1b2020-01-30 22:12:00 -0800933 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100934 put_object(object);
935}
936
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100937/**
938 * kmemleak_alloc - register a newly allocated object
939 * @ptr: pointer to beginning of the object
940 * @size: size of the object
941 * @min_count: minimum number of references to this object. If during memory
942 * scanning a number of references less than @min_count is found,
943 * the object is reported as a memory leak. If @min_count is 0,
944 * the object is never reported as a leak. If @min_count is -1,
945 * the object is ignored (not scanned and not reported as a leak)
946 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
947 *
948 * This function is called from the kernel allocators when a new object
Catalin Marinas94f4a162017-07-06 15:40:22 -0700949 * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100950 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100951void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
952 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100953{
954 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
955
Li Zefan8910ae892014-04-03 14:46:29 -0700956 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100957 create_object((unsigned long)ptr, size, min_count, gfp);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100958}
959EXPORT_SYMBOL_GPL(kmemleak_alloc);
960
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100961/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100962 * kmemleak_alloc_percpu - register a newly allocated __percpu object
963 * @ptr: __percpu pointer to beginning of the object
964 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700965 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100966 *
967 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700968 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100969 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700970void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
971 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100972{
973 unsigned int cpu;
974
975 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
976
977 /*
978 * Percpu allocations are only scanned and not reported as leaks
979 * (min_count is set to 0).
980 */
Li Zefan8910ae892014-04-03 14:46:29 -0700981 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100982 for_each_possible_cpu(cpu)
983 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700984 size, 0, gfp);
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100985}
986EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
987
988/**
Catalin Marinas94f4a162017-07-06 15:40:22 -0700989 * kmemleak_vmalloc - register a newly vmalloc'ed object
990 * @area: pointer to vm_struct
991 * @size: size of the object
992 * @gfp: __vmalloc() flags used for kmemleak internal memory allocations
993 *
994 * This function is called from the vmalloc() kernel allocator when a new
995 * object (memory block) is allocated.
996 */
997void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
998{
999 pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
1000
1001 /*
1002 * A min_count = 2 is needed because vm_struct contains a reference to
1003 * the virtual address of the vmalloc'ed block.
1004 */
1005 if (kmemleak_enabled) {
1006 create_object((unsigned long)area->addr, size, 2, gfp);
1007 object_set_excess_ref((unsigned long)area,
1008 (unsigned long)area->addr);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001009 }
1010}
1011EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
1012
1013/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001014 * kmemleak_free - unregister a previously registered object
1015 * @ptr: pointer to beginning of the object
1016 *
1017 * This function is called from the kernel allocators when an object (memory
1018 * block) is freed (kmem_cache_free, kfree, vfree etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001019 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001020void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001021{
1022 pr_debug("%s(0x%p)\n", __func__, ptr);
1023
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001024 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001025 delete_object_full((unsigned long)ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001026}
1027EXPORT_SYMBOL_GPL(kmemleak_free);
1028
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001029/**
1030 * kmemleak_free_part - partially unregister a previously registered object
1031 * @ptr: pointer to the beginning or inside the object. This also
1032 * represents the start of the range to be freed
1033 * @size: size to be unregistered
1034 *
1035 * This function is called when only a part of a memory block is freed
1036 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +01001037 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001038void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +01001039{
1040 pr_debug("%s(0x%p)\n", __func__, ptr);
1041
Li Zefan8910ae892014-04-03 14:46:29 -07001042 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Patrick Wang0c24e062022-06-11 11:55:50 +08001043 delete_object_part((unsigned long)ptr, size, false);
Catalin Marinas53238a62009-07-07 10:33:00 +01001044}
1045EXPORT_SYMBOL_GPL(kmemleak_free_part);
1046
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001047/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001048 * kmemleak_free_percpu - unregister a previously registered __percpu object
1049 * @ptr: __percpu pointer to beginning of the object
1050 *
1051 * This function is called from the kernel percpu allocator when an object
1052 * (memory block) is freed (free_percpu).
1053 */
1054void __ref kmemleak_free_percpu(const void __percpu *ptr)
1055{
1056 unsigned int cpu;
1057
1058 pr_debug("%s(0x%p)\n", __func__, ptr);
1059
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001060 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001061 for_each_possible_cpu(cpu)
1062 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1063 cpu));
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001064}
1065EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1066
1067/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001068 * kmemleak_update_trace - update object allocation stack trace
1069 * @ptr: pointer to beginning of the object
1070 *
1071 * Override the object allocation stack trace for cases where the actual
1072 * allocation place is not always useful.
1073 */
1074void __ref kmemleak_update_trace(const void *ptr)
1075{
1076 struct kmemleak_object *object;
1077 unsigned long flags;
1078
1079 pr_debug("%s(0x%p)\n", __func__, ptr);
1080
1081 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1082 return;
1083
1084 object = find_and_get_object((unsigned long)ptr, 1);
1085 if (!object) {
1086#ifdef DEBUG
1087 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1088 ptr);
1089#endif
1090 return;
1091 }
1092
He Zhe8c96f1b2020-01-30 22:12:00 -08001093 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinasffe2c742014-06-06 14:38:17 -07001094 object->trace_len = __save_stack_trace(object->trace);
He Zhe8c96f1b2020-01-30 22:12:00 -08001095 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinasffe2c742014-06-06 14:38:17 -07001096
1097 put_object(object);
1098}
1099EXPORT_SYMBOL(kmemleak_update_trace);
1100
1101/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001102 * kmemleak_not_leak - mark an allocated object as false positive
1103 * @ptr: pointer to beginning of the object
1104 *
1105 * Calling this function on an object will cause the memory block to no longer
1106 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001107 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001108void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001109{
1110 pr_debug("%s(0x%p)\n", __func__, ptr);
1111
Li Zefan8910ae892014-04-03 14:46:29 -07001112 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001113 make_gray_object((unsigned long)ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001114}
1115EXPORT_SYMBOL(kmemleak_not_leak);
1116
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001117/**
1118 * kmemleak_ignore - ignore an allocated object
1119 * @ptr: pointer to beginning of the object
1120 *
1121 * Calling this function on an object will cause the memory block to be
1122 * ignored (not scanned and not reported as a leak). This is usually done when
1123 * it is known that the corresponding block is not a leak and does not contain
1124 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001125 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001126void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001127{
1128 pr_debug("%s(0x%p)\n", __func__, ptr);
1129
Li Zefan8910ae892014-04-03 14:46:29 -07001130 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Patrick Wang0c24e062022-06-11 11:55:50 +08001131 make_black_object((unsigned long)ptr, false);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001132}
1133EXPORT_SYMBOL(kmemleak_ignore);
1134
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001135/**
1136 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1137 * @ptr: pointer to beginning or inside the object. This also
1138 * represents the start of the scan area
1139 * @size: size of the scan area
1140 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1141 *
1142 * This function is used when it is known that only certain parts of an object
1143 * contain references to other objects. Kmemleak will only scan these areas
1144 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001145 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001146void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001147{
1148 pr_debug("%s(0x%p)\n", __func__, ptr);
1149
Li Zefan8910ae892014-04-03 14:46:29 -07001150 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001151 add_scan_area((unsigned long)ptr, size, gfp);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001152}
1153EXPORT_SYMBOL(kmemleak_scan_area);
1154
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001155/**
1156 * kmemleak_no_scan - do not scan an allocated object
1157 * @ptr: pointer to beginning of the object
1158 *
1159 * This function notifies kmemleak not to scan the given memory block. Useful
1160 * in situations where it is known that the given object does not contain any
1161 * references to other objects. Kmemleak will not scan such objects reducing
1162 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001163 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001164void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001165{
1166 pr_debug("%s(0x%p)\n", __func__, ptr);
1167
Li Zefan8910ae892014-04-03 14:46:29 -07001168 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001169 object_no_scan((unsigned long)ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001170}
1171EXPORT_SYMBOL(kmemleak_no_scan);
1172
Catalin Marinas9099dae2016-10-11 13:55:11 -07001173/**
1174 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1175 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001176 * @phys: physical address of the object
1177 * @size: size of the object
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001178 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
Catalin Marinas9099dae2016-10-11 13:55:11 -07001179 */
Patrick Wangc200d9002022-06-11 11:55:48 +08001180void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, gfp_t gfp)
Catalin Marinas9099dae2016-10-11 13:55:11 -07001181{
Patrick Wang8e0c4ab2022-06-11 11:55:49 +08001182 pr_debug("%s(0x%pa, %zu)\n", __func__, &phys, size);
1183
Patrick Wang84c32622022-06-11 11:55:51 +08001184 if (kmemleak_enabled)
Patrick Wang8e0c4ab2022-06-11 11:55:49 +08001185 /*
1186 * Create object with OBJECT_PHYS flag and
1187 * assume min_count 0.
1188 */
Patrick Wang0c24e062022-06-11 11:55:50 +08001189 create_object_phys((unsigned long)phys, size, 0, gfp);
Catalin Marinas9099dae2016-10-11 13:55:11 -07001190}
1191EXPORT_SYMBOL(kmemleak_alloc_phys);
1192
1193/**
1194 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1195 * physical address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001196 * @phys: physical address if the beginning or inside an object. This
1197 * also represents the start of the range to be freed
1198 * @size: size to be unregistered
Catalin Marinas9099dae2016-10-11 13:55:11 -07001199 */
1200void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1201{
Patrick Wang0c24e062022-06-11 11:55:50 +08001202 pr_debug("%s(0x%pa)\n", __func__, &phys);
1203
Patrick Wang84c32622022-06-11 11:55:51 +08001204 if (kmemleak_enabled)
Patrick Wang0c24e062022-06-11 11:55:50 +08001205 delete_object_part((unsigned long)phys, size, true);
Catalin Marinas9099dae2016-10-11 13:55:11 -07001206}
1207EXPORT_SYMBOL(kmemleak_free_part_phys);
1208
1209/**
Catalin Marinas9099dae2016-10-11 13:55:11 -07001210 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1211 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001212 * @phys: physical address of the object
Catalin Marinas9099dae2016-10-11 13:55:11 -07001213 */
1214void __ref kmemleak_ignore_phys(phys_addr_t phys)
1215{
Patrick Wang0c24e062022-06-11 11:55:50 +08001216 pr_debug("%s(0x%pa)\n", __func__, &phys);
1217
Patrick Wang84c32622022-06-11 11:55:51 +08001218 if (kmemleak_enabled)
Patrick Wang0c24e062022-06-11 11:55:50 +08001219 make_black_object((unsigned long)phys, true);
Catalin Marinas9099dae2016-10-11 13:55:11 -07001220}
1221EXPORT_SYMBOL(kmemleak_ignore_phys);
1222
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001223/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001224 * Update an object's checksum and return true if it was modified.
1225 */
1226static bool update_checksum(struct kmemleak_object *object)
1227{
1228 u32 old_csum = object->checksum;
1229
Patrick Wang0c24e062022-06-11 11:55:50 +08001230 if (WARN_ON_ONCE(object->flags & OBJECT_PHYS))
1231 return false;
1232
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001233 kasan_disable_current();
Qian Cai69d0b542020-08-14 17:31:14 -07001234 kcsan_disable_current();
Kuan-Ying Lee6c7a00b2021-08-13 16:54:24 -07001235 object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001236 kasan_enable_current();
Qian Cai69d0b542020-08-14 17:31:14 -07001237 kcsan_enable_current();
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001238
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001239 return object->checksum != old_csum;
1240}
1241
1242/*
Catalin Marinas04f70d12017-07-06 15:40:19 -07001243 * Update an object's references. object->lock must be held by the caller.
1244 */
1245static void update_refs(struct kmemleak_object *object)
1246{
1247 if (!color_white(object)) {
1248 /* non-orphan, ignored or new */
1249 return;
1250 }
1251
1252 /*
1253 * Increase the object's reference count (number of pointers to the
1254 * memory block). If this count reaches the required minimum, the
1255 * object's color will become gray and it will be added to the
1256 * gray_list.
1257 */
1258 object->count++;
1259 if (color_gray(object)) {
1260 /* put_object() called when removing from gray_list */
1261 WARN_ON(!get_object(object));
1262 list_add_tail(&object->gray_list, &gray_list);
1263 }
1264}
1265
1266/*
Bhaskar Chowdhury0b5121e2021-04-29 22:54:54 -07001267 * Memory scanning is a long process and it needs to be interruptible. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001268 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001269 */
1270static int scan_should_stop(void)
1271{
Li Zefan8910ae892014-04-03 14:46:29 -07001272 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001273 return 1;
1274
1275 /*
1276 * This function may be called from either process or kthread context,
1277 * hence the need to check for both stop conditions.
1278 */
1279 if (current->mm)
1280 return signal_pending(current);
1281 else
1282 return kthread_should_stop();
1283
1284 return 0;
1285}
1286
1287/*
1288 * Scan a memory block (exclusive range) for valid pointers and add those
1289 * found to the gray list.
1290 */
1291static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001292 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001293{
1294 unsigned long *ptr;
1295 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1296 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001297 unsigned long flags;
Andrey Konovalova2f77572019-02-20 22:19:16 -08001298 unsigned long untagged_ptr;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001299
He Zhe8c96f1b2020-01-30 22:12:00 -08001300 raw_spin_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001301 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001302 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001303 unsigned long pointer;
Catalin Marinas94f4a162017-07-06 15:40:22 -07001304 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001305
1306 if (scan_should_stop())
1307 break;
1308
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001309 kasan_disable_current();
Kuan-Ying Lee6c7a00b2021-08-13 16:54:24 -07001310 pointer = *(unsigned long *)kasan_reset_tag((void *)ptr);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001311 kasan_enable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001312
Andrey Konovalova2f77572019-02-20 22:19:16 -08001313 untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);
1314 if (untagged_ptr < min_addr || untagged_ptr >= max_addr)
Catalin Marinas93ada572015-06-24 16:58:37 -07001315 continue;
1316
1317 /*
1318 * No need for get_object() here since we hold kmemleak_lock.
1319 * object->use_count cannot be dropped to 0 while the object
1320 * is still present in object_tree_root and object_list
1321 * (with updates protected by kmemleak_lock).
1322 */
1323 object = lookup_object(pointer, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001324 if (!object)
1325 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001326 if (object == scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001327 /* self referenced, ignore */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001328 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001329
1330 /*
1331 * Avoid the lockdep recursive warning on object->lock being
1332 * previously acquired in scan_object(). These locks are
1333 * enclosed by scan_mutex.
1334 */
He Zhe8c96f1b2020-01-30 22:12:00 -08001335 raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001336 /* only pass surplus references (object already gray) */
1337 if (color_gray(object)) {
1338 excess_ref = object->excess_ref;
1339 /* no need for update_refs() if object already gray */
1340 } else {
1341 excess_ref = 0;
1342 update_refs(object);
1343 }
He Zhe8c96f1b2020-01-30 22:12:00 -08001344 raw_spin_unlock(&object->lock);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001345
1346 if (excess_ref) {
1347 object = lookup_object(excess_ref, 0);
1348 if (!object)
1349 continue;
1350 if (object == scanned)
1351 /* circular reference, ignore */
1352 continue;
He Zhe8c96f1b2020-01-30 22:12:00 -08001353 raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001354 update_refs(object);
He Zhe8c96f1b2020-01-30 22:12:00 -08001355 raw_spin_unlock(&object->lock);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001356 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001357 }
He Zhe8c96f1b2020-01-30 22:12:00 -08001358 raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001359}
Catalin Marinas0587da42009-10-28 13:33:11 +00001360
Catalin Marinas93ada572015-06-24 16:58:37 -07001361/*
1362 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1363 */
Arnd Bergmanndce5b0b2019-04-18 17:50:48 -07001364#ifdef CONFIG_SMP
Catalin Marinas93ada572015-06-24 16:58:37 -07001365static void scan_large_block(void *start, void *end)
1366{
1367 void *next;
1368
1369 while (start < end) {
1370 next = min(start + MAX_SCAN_SIZE, end);
1371 scan_block(start, next, NULL);
1372 start = next;
1373 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001374 }
1375}
Arnd Bergmanndce5b0b2019-04-18 17:50:48 -07001376#endif
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001377
1378/*
1379 * Scan a memory block corresponding to a kmemleak_object. A condition is
1380 * that object->use_count >= 1.
1381 */
1382static void scan_object(struct kmemleak_object *object)
1383{
1384 struct kmemleak_scan_area *area;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001385 unsigned long flags;
Patrick Wang0c24e062022-06-11 11:55:50 +08001386 void *obj_ptr;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001387
1388 /*
Uwe Kleine-König21ae2952009-10-07 15:21:09 +02001389 * Once the object->lock is acquired, the corresponding memory block
1390 * cannot be freed (the same lock is acquired in delete_object).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001391 */
He Zhe8c96f1b2020-01-30 22:12:00 -08001392 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001393 if (object->flags & OBJECT_NO_SCAN)
1394 goto out;
1395 if (!(object->flags & OBJECT_ALLOCATED))
1396 /* already freed object */
1397 goto out;
Patrick Wang0c24e062022-06-11 11:55:50 +08001398
1399 obj_ptr = object->flags & OBJECT_PHYS ?
1400 __va((phys_addr_t)object->pointer) :
1401 (void *)object->pointer;
1402
Catalin Marinasdba82d92019-09-23 15:33:59 -07001403 if (hlist_empty(&object->area_list) ||
1404 object->flags & OBJECT_FULL_SCAN) {
Patrick Wang0c24e062022-06-11 11:55:50 +08001405 void *start = obj_ptr;
1406 void *end = obj_ptr + object->size;
Catalin Marinas93ada572015-06-24 16:58:37 -07001407 void *next;
Catalin Marinasaf986032009-08-27 14:29:12 +01001408
Catalin Marinas93ada572015-06-24 16:58:37 -07001409 do {
1410 next = min(start + MAX_SCAN_SIZE, end);
1411 scan_block(start, next, object);
1412
1413 start = next;
1414 if (start >= end)
1415 break;
Catalin Marinasaf986032009-08-27 14:29:12 +01001416
He Zhe8c96f1b2020-01-30 22:12:00 -08001417 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinasaf986032009-08-27 14:29:12 +01001418 cond_resched();
He Zhe8c96f1b2020-01-30 22:12:00 -08001419 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001420 } while (object->flags & OBJECT_ALLOCATED);
Catalin Marinasaf986032009-08-27 14:29:12 +01001421 } else
Sasha Levinb67bfe02013-02-27 17:06:00 -08001422 hlist_for_each_entry(area, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001423 scan_block((void *)area->start,
1424 (void *)(area->start + area->size),
Catalin Marinas93ada572015-06-24 16:58:37 -07001425 object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001426out:
He Zhe8c96f1b2020-01-30 22:12:00 -08001427 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001428}
1429
1430/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001431 * Scan the objects already referenced (gray objects). More objects will be
1432 * referenced and, if there are no memory leaks, all the objects are scanned.
1433 */
1434static void scan_gray_list(void)
1435{
1436 struct kmemleak_object *object, *tmp;
1437
1438 /*
1439 * The list traversal is safe for both tail additions and removals
1440 * from inside the loop. The kmemleak objects cannot be freed from
1441 * outside the loop because their use_count was incremented.
1442 */
1443 object = list_entry(gray_list.next, typeof(*object), gray_list);
1444 while (&object->gray_list != &gray_list) {
1445 cond_resched();
1446
1447 /* may add new objects to the list */
1448 if (!scan_should_stop())
1449 scan_object(object);
1450
1451 tmp = list_entry(object->gray_list.next, typeof(*object),
1452 gray_list);
1453
1454 /* remove the object from the list and release it */
1455 list_del(&object->gray_list);
1456 put_object(object);
1457
1458 object = tmp;
1459 }
1460 WARN_ON(!list_empty(&gray_list));
1461}
1462
1463/*
Waiman Long984a6082022-10-20 13:56:19 -04001464 * Conditionally call resched() in a object iteration loop while making sure
1465 * that the given object won't go away without RCU read lock by performing a
1466 * get_object() if !pinned.
1467 *
1468 * Return: false if can't do a cond_resched() due to get_object() failure
1469 * true otherwise
1470 */
1471static bool kmemleak_cond_resched(struct kmemleak_object *object, bool pinned)
1472{
1473 if (!pinned && !get_object(object))
1474 return false;
1475
1476 rcu_read_unlock();
1477 cond_resched();
1478 rcu_read_lock();
1479 if (!pinned)
1480 put_object(object);
1481 return true;
1482}
1483
1484/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001485 * Scan data sections and all the referenced memory blocks allocated via the
1486 * kernel's standard allocators. This function must be called with the
1487 * scan_mutex held.
1488 */
1489static void kmemleak_scan(void)
1490{
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001491 struct kmemleak_object *object;
Lang Yuc10a0f82022-02-03 20:49:37 -08001492 struct zone *zone;
1493 int __maybe_unused i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001494 int new_leaks = 0;
Waiman Long984a6082022-10-20 13:56:19 -04001495 int loop_cnt = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001496
Catalin Marinasacf49682009-06-26 17:38:29 +01001497 jiffies_last_scan = jiffies;
1498
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001499 /* prepare the kmemleak_object's */
1500 rcu_read_lock();
1501 list_for_each_entry_rcu(object, &object_list, object_list) {
Waiman Long6edda042022-06-14 18:03:59 -04001502 bool obj_pinned = false;
1503
Waiman Long00c15502022-06-14 18:03:57 -04001504 raw_spin_lock_irq(&object->lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001505#ifdef DEBUG
1506 /*
1507 * With a few exceptions there should be a maximum of
1508 * 1 reference to any object at this point.
1509 */
1510 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001511 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001512 atomic_read(&object->use_count));
1513 dump_object_info(object);
1514 }
1515#endif
Patrick Wang84c32622022-06-11 11:55:51 +08001516
1517 /* ignore objects outside lowmem (paint them black) */
1518 if ((object->flags & OBJECT_PHYS) &&
1519 !(object->flags & OBJECT_NO_SCAN)) {
1520 unsigned long phys = object->pointer;
1521
1522 if (PHYS_PFN(phys) < min_low_pfn ||
1523 PHYS_PFN(phys + object->size) >= max_low_pfn)
1524 __paint_it(object, KMEMLEAK_BLACK);
1525 }
1526
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001527 /* reset the reference count (whiten the object) */
1528 object->count = 0;
Waiman Long6edda042022-06-14 18:03:59 -04001529 if (color_gray(object) && get_object(object)) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001530 list_add_tail(&object->gray_list, &gray_list);
Waiman Long6edda042022-06-14 18:03:59 -04001531 obj_pinned = true;
1532 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001533
Waiman Long00c15502022-06-14 18:03:57 -04001534 raw_spin_unlock_irq(&object->lock);
Waiman Long6edda042022-06-14 18:03:59 -04001535
1536 /*
Waiman Long984a6082022-10-20 13:56:19 -04001537 * Do a cond_resched() every 64k objects to avoid soft lockup.
Waiman Long6edda042022-06-14 18:03:59 -04001538 */
Waiman Long984a6082022-10-20 13:56:19 -04001539 if (!(++loop_cnt & 0xffff) &&
1540 !kmemleak_cond_resched(object, obj_pinned))
1541 loop_cnt--; /* Try again on next object */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001542 }
1543 rcu_read_unlock();
1544
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001545#ifdef CONFIG_SMP
1546 /* per-cpu sections scanning */
1547 for_each_possible_cpu(i)
Catalin Marinas93ada572015-06-24 16:58:37 -07001548 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1549 __per_cpu_end + per_cpu_offset(i));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001550#endif
1551
1552 /*
Laura Abbott029aeff2011-11-15 23:49:09 +00001553 * Struct page scanning for each node.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001554 */
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001555 get_online_mems();
Lang Yuc10a0f82022-02-03 20:49:37 -08001556 for_each_populated_zone(zone) {
1557 unsigned long start_pfn = zone->zone_start_pfn;
1558 unsigned long end_pfn = zone_end_pfn(zone);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001559 unsigned long pfn;
1560
1561 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
Oscar Salvador9f1eb382018-12-28 00:37:57 -08001562 struct page *page = pfn_to_online_page(pfn);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001563
Oscar Salvador9f1eb382018-12-28 00:37:57 -08001564 if (!page)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001565 continue;
Oscar Salvador9f1eb382018-12-28 00:37:57 -08001566
Lang Yuc10a0f82022-02-03 20:49:37 -08001567 /* only scan pages belonging to this zone */
1568 if (page_zone(page) != zone)
Oscar Salvador9f1eb382018-12-28 00:37:57 -08001569 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001570 /* only scan if page is in use */
1571 if (page_count(page) == 0)
1572 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001573 scan_block(page, page + 1, NULL);
Andrew Morton13ab183d2017-12-14 15:32:31 -08001574 if (!(pfn & 63))
Yisheng Xiebde5f6b2017-11-29 16:11:08 -08001575 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001576 }
1577 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001578 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001579
1580 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001581 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001582 */
1583 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001584 struct task_struct *p, *g;
1585
Davidlohr Buesoc4b28962020-10-13 16:48:50 -07001586 rcu_read_lock();
1587 for_each_process_thread(g, p) {
Catalin Marinas37df49f2016-10-27 17:46:47 -07001588 void *stack = try_get_task_stack(p);
1589 if (stack) {
1590 scan_block(stack, stack + THREAD_SIZE, NULL);
1591 put_task_stack(p);
1592 }
Davidlohr Buesoc4b28962020-10-13 16:48:50 -07001593 }
1594 rcu_read_unlock();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001595 }
1596
1597 /*
1598 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001599 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001600 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001601 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001602
1603 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001604 * Check for new or unreferenced objects modified since the previous
1605 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001606 */
1607 rcu_read_lock();
Waiman Long984a6082022-10-20 13:56:19 -04001608 loop_cnt = 0;
Catalin Marinas25873622009-07-07 10:32:58 +01001609 list_for_each_entry_rcu(object, &object_list, object_list) {
Waiman Long64977912022-06-14 18:03:58 -04001610 /*
Waiman Long984a6082022-10-20 13:56:19 -04001611 * Do a cond_resched() every 64k objects to avoid soft lockup.
1612 */
1613 if (!(++loop_cnt & 0xffff) &&
1614 !kmemleak_cond_resched(object, false))
1615 loop_cnt--; /* Try again on next object */
1616
1617 /*
Waiman Long64977912022-06-14 18:03:58 -04001618 * This is racy but we can save the overhead of lock/unlock
1619 * calls. The missed objects, if any, should be caught in
1620 * the next scan.
1621 */
1622 if (!color_white(object))
1623 continue;
Waiman Long00c15502022-06-14 18:03:57 -04001624 raw_spin_lock_irq(&object->lock);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001625 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1626 && update_checksum(object) && get_object(object)) {
1627 /* color it gray temporarily */
1628 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001629 list_add_tail(&object->gray_list, &gray_list);
1630 }
Waiman Long00c15502022-06-14 18:03:57 -04001631 raw_spin_unlock_irq(&object->lock);
Catalin Marinas25873622009-07-07 10:32:58 +01001632 }
1633 rcu_read_unlock();
1634
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001635 /*
1636 * Re-scan the gray list for modified unreferenced objects.
1637 */
1638 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001639
1640 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001641 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001642 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001643 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001644 return;
1645
1646 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001647 * Scanning result reporting.
1648 */
1649 rcu_read_lock();
Waiman Long984a6082022-10-20 13:56:19 -04001650 loop_cnt = 0;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001651 list_for_each_entry_rcu(object, &object_list, object_list) {
Waiman Long64977912022-06-14 18:03:58 -04001652 /*
Waiman Long984a6082022-10-20 13:56:19 -04001653 * Do a cond_resched() every 64k objects to avoid soft lockup.
1654 */
1655 if (!(++loop_cnt & 0xffff) &&
1656 !kmemleak_cond_resched(object, false))
1657 loop_cnt--; /* Try again on next object */
1658
1659 /*
Waiman Long64977912022-06-14 18:03:58 -04001660 * This is racy but we can save the overhead of lock/unlock
1661 * calls. The missed objects, if any, should be caught in
1662 * the next scan.
1663 */
1664 if (!color_white(object))
1665 continue;
Waiman Long00c15502022-06-14 18:03:57 -04001666 raw_spin_lock_irq(&object->lock);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001667 if (unreferenced_object(object) &&
1668 !(object->flags & OBJECT_REPORTED)) {
1669 object->flags |= OBJECT_REPORTED;
Vincent Whitchurch154221c2018-10-26 15:03:42 -07001670
1671 if (kmemleak_verbose)
1672 print_unreferenced(NULL, object);
1673
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001674 new_leaks++;
1675 }
Waiman Long00c15502022-06-14 18:03:57 -04001676 raw_spin_unlock_irq(&object->lock);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001677 }
1678 rcu_read_unlock();
1679
Li Zefandc9b3f42014-04-03 14:46:26 -07001680 if (new_leaks) {
1681 kmemleak_found_leaks = true;
1682
Joe Perches756a0252016-03-17 14:19:47 -07001683 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1684 new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001685 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001686
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001687}
1688
1689/*
1690 * Thread function performing automatic memory scanning. Unreferenced objects
1691 * at the end of a memory scan are reported but only the first time.
1692 */
1693static int kmemleak_scan_thread(void *arg)
1694{
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -08001695 static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001696
Joe Perchesae281062009-06-23 14:40:26 +01001697 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001698 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001699
1700 /*
1701 * Wait before the first scan to allow the system to fully initialize.
1702 */
1703 if (first_run) {
Vegard Nossum98c42d92016-07-28 15:48:32 -07001704 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001705 first_run = 0;
Vegard Nossum98c42d92016-07-28 15:48:32 -07001706 while (timeout && !kthread_should_stop())
1707 timeout = schedule_timeout_interruptible(timeout);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001708 }
1709
1710 while (!kthread_should_stop()) {
Yanfei Xu54dd2002021-06-28 19:35:01 -07001711 signed long timeout = READ_ONCE(jiffies_scan_wait);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001712
1713 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001714 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001715 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001716
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001717 /* wait before the next scan */
1718 while (timeout && !kthread_should_stop())
1719 timeout = schedule_timeout_interruptible(timeout);
1720 }
1721
Joe Perchesae281062009-06-23 14:40:26 +01001722 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001723
1724 return 0;
1725}
1726
1727/*
1728 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001729 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001730 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001731static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001732{
1733 if (scan_thread)
1734 return;
1735 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1736 if (IS_ERR(scan_thread)) {
Joe Perches598d8092016-03-17 14:19:44 -07001737 pr_warn("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001738 scan_thread = NULL;
1739 }
1740}
1741
1742/*
Vinayak Menon914b6df2018-03-28 16:01:16 -07001743 * Stop the automatic memory scanning thread.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001744 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001745static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001746{
1747 if (scan_thread) {
1748 kthread_stop(scan_thread);
1749 scan_thread = NULL;
1750 }
1751}
1752
1753/*
1754 * Iterate over the object_list and return the first valid object at or after
1755 * the required position with its use_count incremented. The function triggers
1756 * a memory scanning when the pos argument points to the first position.
1757 */
1758static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1759{
1760 struct kmemleak_object *object;
1761 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001762 int err;
1763
1764 err = mutex_lock_interruptible(&scan_mutex);
1765 if (err < 0)
1766 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001767
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001768 rcu_read_lock();
1769 list_for_each_entry_rcu(object, &object_list, object_list) {
1770 if (n-- > 0)
1771 continue;
1772 if (get_object(object))
1773 goto out;
1774 }
1775 object = NULL;
1776out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001777 return object;
1778}
1779
1780/*
1781 * Return the next object in the object_list. The function decrements the
1782 * use_count of the previous object and increases that of the next one.
1783 */
1784static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1785{
1786 struct kmemleak_object *prev_obj = v;
1787 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001788 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001789
1790 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001791
Michael Wang58fac092012-08-17 12:33:34 +08001792 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001793 if (get_object(obj)) {
1794 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001795 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001796 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001797 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001798
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001799 put_object(prev_obj);
1800 return next_obj;
1801}
1802
1803/*
1804 * Decrement the use_count of the last object required, if any.
1805 */
1806static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1807{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001808 if (!IS_ERR(v)) {
1809 /*
1810 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1811 * waiting was interrupted, so only release it if !IS_ERR.
1812 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001813 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001814 mutex_unlock(&scan_mutex);
1815 if (v)
1816 put_object(v);
1817 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001818}
1819
1820/*
1821 * Print the information for an unreferenced object to the seq file.
1822 */
1823static int kmemleak_seq_show(struct seq_file *seq, void *v)
1824{
1825 struct kmemleak_object *object = v;
1826 unsigned long flags;
1827
He Zhe8c96f1b2020-01-30 22:12:00 -08001828 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001829 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001830 print_unreferenced(seq, object);
He Zhe8c96f1b2020-01-30 22:12:00 -08001831 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001832 return 0;
1833}
1834
1835static const struct seq_operations kmemleak_seq_ops = {
1836 .start = kmemleak_seq_start,
1837 .next = kmemleak_seq_next,
1838 .stop = kmemleak_seq_stop,
1839 .show = kmemleak_seq_show,
1840};
1841
1842static int kmemleak_open(struct inode *inode, struct file *file)
1843{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001844 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001845}
1846
Catalin Marinas189d84e2009-08-27 14:29:15 +01001847static int dump_str_object_info(const char *str)
1848{
1849 unsigned long flags;
1850 struct kmemleak_object *object;
1851 unsigned long addr;
1852
Abhijit Pawardc053732012-12-18 14:23:27 -08001853 if (kstrtoul(str, 0, &addr))
1854 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001855 object = find_and_get_object(addr, 0);
1856 if (!object) {
1857 pr_info("Unknown object at 0x%08lx\n", addr);
1858 return -EINVAL;
1859 }
1860
He Zhe8c96f1b2020-01-30 22:12:00 -08001861 raw_spin_lock_irqsave(&object->lock, flags);
Catalin Marinas189d84e2009-08-27 14:29:15 +01001862 dump_object_info(object);
He Zhe8c96f1b2020-01-30 22:12:00 -08001863 raw_spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas189d84e2009-08-27 14:29:15 +01001864
1865 put_object(object);
1866 return 0;
1867}
1868
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001869/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001870 * We use grey instead of black to ensure we can do future scans on the same
1871 * objects. If we did not do future scans these black objects could
1872 * potentially contain references to newly allocated objects in the future and
1873 * we'd end up with false positives.
1874 */
1875static void kmemleak_clear(void)
1876{
1877 struct kmemleak_object *object;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001878
1879 rcu_read_lock();
1880 list_for_each_entry_rcu(object, &object_list, object_list) {
Waiman Long00c15502022-06-14 18:03:57 -04001881 raw_spin_lock_irq(&object->lock);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001882 if ((object->flags & OBJECT_REPORTED) &&
1883 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001884 __paint_it(object, KMEMLEAK_GREY);
Waiman Long00c15502022-06-14 18:03:57 -04001885 raw_spin_unlock_irq(&object->lock);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001886 }
1887 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001888
1889 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001890}
1891
Li Zefanc89da702014-04-03 14:46:27 -07001892static void __kmemleak_do_cleanup(void);
1893
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001894/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001895 * File write operation to configure kmemleak at run-time. The following
1896 * commands can be written to the /sys/kernel/debug/kmemleak file:
1897 * off - disable kmemleak (irreversible)
1898 * stack=on - enable the task stacks scanning
1899 * stack=off - disable the tasks stacks scanning
1900 * scan=on - start the automatic memory scanning thread
1901 * scan=off - stop the automatic memory scanning thread
1902 * scan=... - set the automatic memory scanning period in seconds (0 to
1903 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001904 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001905 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001906 * grey to ignore printing them, or free all kmemleak objects
1907 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001908 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001909 */
1910static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1911 size_t size, loff_t *ppos)
1912{
1913 char buf[64];
1914 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001915 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001916
1917 buf_size = min(size, (sizeof(buf) - 1));
1918 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1919 return -EFAULT;
1920 buf[buf_size] = 0;
1921
Catalin Marinasb87324d2009-07-07 10:32:58 +01001922 ret = mutex_lock_interruptible(&scan_mutex);
1923 if (ret < 0)
1924 return ret;
1925
Li Zefanc89da702014-04-03 14:46:27 -07001926 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae892014-04-03 14:46:29 -07001927 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001928 kmemleak_clear();
1929 else
1930 __kmemleak_do_cleanup();
1931 goto out;
1932 }
1933
Li Zefan8910ae892014-04-03 14:46:29 -07001934 if (!kmemleak_enabled) {
André Almeida4e4dfce2019-07-11 20:53:43 -07001935 ret = -EPERM;
Li Zefanc89da702014-04-03 14:46:27 -07001936 goto out;
1937 }
1938
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001939 if (strncmp(buf, "off", 3) == 0)
1940 kmemleak_disable();
1941 else if (strncmp(buf, "stack=on", 8) == 0)
1942 kmemleak_stack_scan = 1;
1943 else if (strncmp(buf, "stack=off", 9) == 0)
1944 kmemleak_stack_scan = 0;
1945 else if (strncmp(buf, "scan=on", 7) == 0)
1946 start_scan_thread();
1947 else if (strncmp(buf, "scan=off", 8) == 0)
1948 stop_scan_thread();
1949 else if (strncmp(buf, "scan=", 5) == 0) {
Yanfei Xu54dd2002021-06-28 19:35:01 -07001950 unsigned secs;
1951 unsigned long msecs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001952
Yanfei Xu54dd2002021-06-28 19:35:01 -07001953 ret = kstrtouint(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001954 if (ret < 0)
1955 goto out;
Yanfei Xu54dd2002021-06-28 19:35:01 -07001956
1957 msecs = secs * MSEC_PER_SEC;
1958 if (msecs > UINT_MAX)
1959 msecs = UINT_MAX;
1960
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001961 stop_scan_thread();
Yanfei Xu54dd2002021-06-28 19:35:01 -07001962 if (msecs) {
1963 WRITE_ONCE(jiffies_scan_wait, msecs_to_jiffies(msecs));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001964 start_scan_thread();
1965 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001966 } else if (strncmp(buf, "scan", 4) == 0)
1967 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001968 else if (strncmp(buf, "dump=", 5) == 0)
1969 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001970 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001971 ret = -EINVAL;
1972
1973out:
1974 mutex_unlock(&scan_mutex);
1975 if (ret < 0)
1976 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001977
1978 /* ignore the rest of the buffer, only one command at a time */
1979 *ppos += size;
1980 return size;
1981}
1982
1983static const struct file_operations kmemleak_fops = {
1984 .owner = THIS_MODULE,
1985 .open = kmemleak_open,
1986 .read = seq_read,
1987 .write = kmemleak_write,
1988 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001989 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001990};
1991
Li Zefanc89da702014-04-03 14:46:27 -07001992static void __kmemleak_do_cleanup(void)
1993{
Catalin Marinas2abd8392019-10-04 14:46:24 +01001994 struct kmemleak_object *object, *tmp;
Li Zefanc89da702014-04-03 14:46:27 -07001995
Catalin Marinas2abd8392019-10-04 14:46:24 +01001996 /*
1997 * Kmemleak has already been disabled, no need for RCU list traversal
1998 * or kmemleak_lock held.
1999 */
2000 list_for_each_entry_safe(object, tmp, &object_list, object_list) {
2001 __remove_object(object);
2002 __delete_object(object);
2003 }
Li Zefanc89da702014-04-03 14:46:27 -07002004}
2005
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002006/*
Catalin Marinas74341702011-09-29 11:50:07 +01002007 * Stop the memory scanning thread and free the kmemleak internal objects if
2008 * no previous scan thread (otherwise, kmemleak may still have some useful
2009 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002010 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002011static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002012{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002013 stop_scan_thread();
2014
Vinayak Menon914b6df2018-03-28 16:01:16 -07002015 mutex_lock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002016 /*
Vinayak Menon914b6df2018-03-28 16:01:16 -07002017 * Once it is made sure that kmemleak_scan has stopped, it is safe to no
2018 * longer track object freeing. Ordering of the scan thread stopping and
2019 * the memory accesses below is guaranteed by the kthread_stop()
2020 * function.
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002021 */
2022 kmemleak_free_enabled = 0;
Vinayak Menon914b6df2018-03-28 16:01:16 -07002023 mutex_unlock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002024
Li Zefanc89da702014-04-03 14:46:27 -07002025 if (!kmemleak_found_leaks)
2026 __kmemleak_do_cleanup();
2027 else
Joe Perches756a0252016-03-17 14:19:47 -07002028 pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002029}
2030
Catalin Marinas179a8102009-09-07 10:14:42 +01002031static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002032
2033/*
2034 * Disable kmemleak. No memory allocation/freeing will be traced once this
2035 * function is called. Disabling kmemleak is an irreversible operation.
2036 */
2037static void kmemleak_disable(void)
2038{
2039 /* atomically check whether it was already invoked */
Li Zefan8910ae892014-04-03 14:46:29 -07002040 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002041 return;
2042
2043 /* stop any memory operation tracing */
Li Zefan8910ae892014-04-03 14:46:29 -07002044 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002045
2046 /* check whether it is too early for a kernel thread */
Li Zefan8910ae892014-04-03 14:46:29 -07002047 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01002048 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002049 else
2050 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002051
2052 pr_info("Kernel memory leak detector disabled\n");
2053}
2054
2055/*
2056 * Allow boot-time kmemleak disabling (enabled by default).
2057 */
Dou Liyang8bd30c12018-04-05 16:23:46 -07002058static int __init kmemleak_boot_config(char *str)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002059{
2060 if (!str)
2061 return -EINVAL;
2062 if (strcmp(str, "off") == 0)
2063 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01002064 else if (strcmp(str, "on") == 0)
2065 kmemleak_skip_disable = 1;
2066 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002067 return -EINVAL;
2068 return 0;
2069}
2070early_param("kmemleak", kmemleak_boot_config);
2071
2072/*
Catalin Marinas20301172009-06-17 18:29:04 +01002073 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002074 */
2075void __init kmemleak_init(void)
2076{
Jason Baronab0155a2010-07-19 11:54:17 +01002077#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
2078 if (!kmemleak_skip_disable) {
2079 kmemleak_disable();
2080 return;
2081 }
2082#endif
2083
Catalin Marinasc5665862019-09-23 15:34:05 -07002084 if (kmemleak_error)
2085 return;
2086
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002087 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
2088 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
2089
2090 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
2091 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002092
Catalin Marinas298a32b2019-04-05 18:38:49 -07002093 /* register the data/bss sections */
2094 create_object((unsigned long)_sdata, _edata - _sdata,
2095 KMEMLEAK_GREY, GFP_ATOMIC);
2096 create_object((unsigned long)__bss_start, __bss_stop - __bss_start,
2097 KMEMLEAK_GREY, GFP_ATOMIC);
2098 /* only register .data..ro_after_init if not within .data */
Nathan Chancellorb0d14fc2020-04-01 21:04:34 -07002099 if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata)
Catalin Marinas298a32b2019-04-05 18:38:49 -07002100 create_object((unsigned long)__start_ro_after_init,
2101 __end_ro_after_init - __start_ro_after_init,
2102 KMEMLEAK_GREY, GFP_ATOMIC);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002103}
2104
2105/*
2106 * Late initialization function.
2107 */
2108static int __init kmemleak_late_init(void)
2109{
Li Zefan8910ae892014-04-03 14:46:29 -07002110 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002111
Greg Kroah-Hartman282401d2019-01-22 16:21:12 +01002112 debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops);
Vincent Whitchurchb3537562018-09-04 15:45:44 -07002113
Li Zefan8910ae892014-04-03 14:46:29 -07002114 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002115 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002116 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002117 * small chance that kmemleak_disable() was called immediately
2118 * after setting kmemleak_initialized and we may end up with
2119 * two clean-up threads but serialized by scan_mutex.
2120 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002121 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002122 return -ENOMEM;
2123 }
2124
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -08002125 if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) {
2126 mutex_lock(&scan_mutex);
2127 start_scan_thread();
2128 mutex_unlock(&scan_mutex);
2129 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002130
Qian Cai0e965a62019-09-23 15:34:07 -07002131 pr_info("Kernel memory leak detector initialized (mem pool available: %d)\n",
2132 mem_pool_free_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002133
2134 return 0;
2135}
2136late_initcall(kmemleak_late_init);