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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 *
16 * - kmemleak_lock (rwlock): protects the object_list modifications and
17 * accesses to the object_tree_root. The object_list is the main list
18 * holding the metadata (struct kmemleak_object) for the allocated memory
Michel Lespinasse85d3a312012-10-08 16:31:27 -070019 * blocks. The object_tree_root is a red black tree used to look-up
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010020 * metadata based on a pointer to the corresponding memory block. The
21 * kmemleak_object structures are added to the object_list and
22 * object_tree_root in the create_object() function called from the
23 * kmemleak_alloc() callback and removed in delete_object() called from the
24 * kmemleak_free() callback
25 * - kmemleak_object.lock (spinlock): protects a kmemleak_object. Accesses to
26 * the metadata (e.g. count) are protected by this lock. Note that some
27 * members of this structure may be protected by other means (atomic or
28 * kmemleak_lock). This lock is also held when scanning the corresponding
29 * memory block to avoid the kernel freeing it via the kmemleak_free()
30 * callback. This is less heavyweight than holding a global lock like
31 * kmemleak_lock during scanning
32 * - scan_mutex (mutex): ensures that only one thread may scan the memory for
33 * unreferenced objects at a time. The gray_list contains the objects which
34 * are already referenced or marked as false positives and need to be
35 * scanned. This list is only modified during a scanning episode when the
36 * scan_mutex is held. At the end of a scan, the gray_list is always empty.
37 * Note that the kmemleak_object.use_count is incremented when an object is
Catalin Marinas4698c1f2009-06-26 17:38:27 +010038 * added to the gray_list and therefore cannot be freed. This mutex also
39 * prevents multiple users of the "kmemleak" debugfs file together with
40 * modifications to the memory scanning parameters including the scan_thread
41 * pointer
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010042 *
Catalin Marinas93ada572015-06-24 16:58:37 -070043 * Locks and mutexes are acquired/nested in the following order:
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070044 *
Catalin Marinas93ada572015-06-24 16:58:37 -070045 * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING)
46 *
47 * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex
48 * regions.
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070049 *
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010050 * The kmemleak_object structures have a use_count incremented or decremented
51 * using the get_object()/put_object() functions. When the use_count becomes
52 * 0, this count can no longer be incremented and put_object() schedules the
53 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
54 * function must be protected by rcu_read_lock() to avoid accessing a freed
55 * structure.
56 */
57
Joe Perchesae281062009-06-23 14:40:26 +010058#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
59
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010060#include <linux/init.h>
61#include <linux/kernel.h>
62#include <linux/list.h>
Ingo Molnar3f07c012017-02-08 18:51:30 +010063#include <linux/sched/signal.h>
Ingo Molnar29930022017-02-08 18:51:36 +010064#include <linux/sched/task.h>
Ingo Molnar68db0cf2017-02-08 18:51:37 +010065#include <linux/sched/task_stack.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010066#include <linux/jiffies.h>
67#include <linux/delay.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040068#include <linux/export.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010069#include <linux/kthread.h>
Michel Lespinasse85d3a312012-10-08 16:31:27 -070070#include <linux/rbtree.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010071#include <linux/fs.h>
72#include <linux/debugfs.h>
73#include <linux/seq_file.h>
74#include <linux/cpumask.h>
75#include <linux/spinlock.h>
Vincent Whitchurch154221c2018-10-26 15:03:42 -070076#include <linux/module.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010077#include <linux/mutex.h>
78#include <linux/rcupdate.h>
79#include <linux/stacktrace.h>
80#include <linux/cache.h>
81#include <linux/percpu.h>
Mike Rapoport57c8a662018-10-30 15:09:49 -070082#include <linux/memblock.h>
Catalin Marinas9099dae2016-10-11 13:55:11 -070083#include <linux/pfn.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010084#include <linux/mmzone.h>
85#include <linux/slab.h>
86#include <linux/thread_info.h>
87#include <linux/err.h>
88#include <linux/uaccess.h>
89#include <linux/string.h>
90#include <linux/nodemask.h>
91#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +010092#include <linux/workqueue.h>
Catalin Marinas04609ccc2009-10-28 13:33:12 +000093#include <linux/crc32.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010094
95#include <asm/sections.h>
96#include <asm/processor.h>
Arun Sharma600634972011-07-26 16:09:06 -070097#include <linux/atomic.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010098
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -080099#include <linux/kasan.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100100#include <linux/kmemleak.h>
Laura Abbott029aeff2011-11-15 23:49:09 +0000101#include <linux/memory_hotplug.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100102
103/*
104 * Kmemleak configuration and common defines.
105 */
106#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100107#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100108#define SECS_FIRST_SCAN 60 /* delay before the first scan */
109#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinasaf986032009-08-27 14:29:12 +0100110#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100111
112#define BYTES_PER_POINTER sizeof(void *)
113
Catalin Marinas216c04b2009-06-17 18:29:02 +0100114/* GFP bitmask for kmemleak internal allocations */
Vladimir Davydov20b5c302016-01-14 15:18:08 -0800115#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000116 __GFP_NORETRY | __GFP_NOMEMALLOC | \
Dmitry Vyukovd9570ee2018-01-12 16:53:10 -0800117 __GFP_NOWARN | __GFP_NOFAIL)
Catalin Marinas216c04b2009-06-17 18:29:02 +0100118
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100119/* scanning area inside a memory block */
120struct kmemleak_scan_area {
121 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000122 unsigned long start;
123 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100124};
125
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700126#define KMEMLEAK_GREY 0
127#define KMEMLEAK_BLACK -1
128
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100129/*
130 * Structure holding the metadata for each allocated memory block.
131 * Modifications to such objects should be made while holding the
132 * object->lock. Insertions or deletions from object_list, gray_list or
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700133 * rb_node are already protected by the corresponding locks or mutex (see
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100134 * the notes on locking above). These objects are reference-counted
135 * (use_count) and freed using the RCU mechanism.
136 */
137struct kmemleak_object {
138 spinlock_t lock;
Catalin Marinasf66abf02017-07-06 15:40:16 -0700139 unsigned int flags; /* object status flags */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100140 struct list_head object_list;
141 struct list_head gray_list;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700142 struct rb_node rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100143 struct rcu_head rcu; /* object_list lockless traversal */
144 /* object usage count; object freed when use_count == 0 */
145 atomic_t use_count;
146 unsigned long pointer;
147 size_t size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700148 /* pass surplus references to this pointer */
149 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100150 /* minimum number of a pointers found before it is considered leak */
151 int min_count;
152 /* the total number of pointers found pointing to this object */
153 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000154 /* checksum for detecting modified objects */
155 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100156 /* memory ranges to be scanned inside an object (empty for all) */
157 struct hlist_head area_list;
158 unsigned long trace[MAX_TRACE];
159 unsigned int trace_len;
160 unsigned long jiffies; /* creation timestamp */
161 pid_t pid; /* pid of the current task */
162 char comm[TASK_COMM_LEN]; /* executable name */
163};
164
165/* flag representing the memory block allocation status */
166#define OBJECT_ALLOCATED (1 << 0)
167/* flag set after the first reporting of an unreference object */
168#define OBJECT_REPORTED (1 << 1)
169/* flag set to not scan the object */
170#define OBJECT_NO_SCAN (1 << 2)
171
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700172#define HEX_PREFIX " "
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100173/* number of bytes to print per line; must be 16 or 32 */
174#define HEX_ROW_SIZE 16
175/* number of bytes to print at a time (1, 2, 4, 8) */
176#define HEX_GROUP_SIZE 1
177/* include ASCII after the hex output */
178#define HEX_ASCII 1
179/* max number of lines to be printed */
180#define HEX_MAX_LINES 2
181
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100182/* the list of all allocated objects */
183static LIST_HEAD(object_list);
184/* the list of gray-colored objects (see color_gray comment below) */
185static LIST_HEAD(gray_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700186/* search tree for object boundaries */
187static struct rb_root object_tree_root = RB_ROOT;
188/* rw_lock protecting the access to object_list and object_tree_root */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100189static DEFINE_RWLOCK(kmemleak_lock);
190
191/* allocation caches for kmemleak internal data */
192static struct kmem_cache *object_cache;
193static struct kmem_cache *scan_area_cache;
194
195/* set if tracing memory operations is enabled */
Li Zefan8910ae892014-04-03 14:46:29 -0700196static int kmemleak_enabled;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700197/* same as above but only for the kmemleak_free() callback */
198static int kmemleak_free_enabled;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100199/* set in the late_initcall if there were no errors */
Li Zefan8910ae892014-04-03 14:46:29 -0700200static int kmemleak_initialized;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100201/* enables or disables early logging of the memory operations */
Li Zefan8910ae892014-04-03 14:46:29 -0700202static int kmemleak_early_log = 1;
Catalin Marinas5f790202011-09-28 12:17:03 +0100203/* set if a kmemleak warning was issued */
Li Zefan8910ae892014-04-03 14:46:29 -0700204static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100205/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae892014-04-03 14:46:29 -0700206static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100207
208/* minimum and maximum address that may be valid pointers */
209static unsigned long min_addr = ULONG_MAX;
210static unsigned long max_addr;
211
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100212static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100213/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100214static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100215static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100216/* delay between automatic memory scannings */
217static signed long jiffies_scan_wait;
218/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100219static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100220/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100221static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100222/* setting kmemleak=on, will set this var, skipping the disable */
223static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700224/* If there are leaks that can be reported */
225static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100226
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700227static bool kmemleak_verbose;
228module_param_named(verbose, kmemleak_verbose, bool, 0600);
229
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100230/*
Catalin Marinas20301172009-06-17 18:29:04 +0100231 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100232 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100233 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100234 * arbitrary buffer to hold the allocation/freeing information before it is
235 * fully initialized.
236 */
237
238/* kmemleak operation type for early logging */
239enum {
240 KMEMLEAK_ALLOC,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100241 KMEMLEAK_ALLOC_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100242 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100243 KMEMLEAK_FREE_PART,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100244 KMEMLEAK_FREE_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100245 KMEMLEAK_NOT_LEAK,
246 KMEMLEAK_IGNORE,
247 KMEMLEAK_SCAN_AREA,
Catalin Marinas94f4a162017-07-06 15:40:22 -0700248 KMEMLEAK_NO_SCAN,
249 KMEMLEAK_SET_EXCESS_REF
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100250};
251
252/*
253 * Structure holding the information passed to kmemleak callbacks during the
254 * early logging.
255 */
256struct early_log {
257 int op_type; /* kmemleak operation type */
Catalin Marinasf66abf02017-07-06 15:40:16 -0700258 int min_count; /* minimum reference count */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100259 const void *ptr; /* allocated/freed memory block */
Catalin Marinas94f4a162017-07-06 15:40:22 -0700260 union {
261 size_t size; /* memory block size */
262 unsigned long excess_ref; /* surplus reference passing */
263 };
Catalin Marinasfd678962009-08-27 14:29:17 +0100264 unsigned long trace[MAX_TRACE]; /* stack trace */
265 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100266};
267
268/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100269static struct early_log
270 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
271static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100272
273static void kmemleak_disable(void);
274
275/*
276 * Print a warning and dump the stack trace.
277 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100278#define kmemleak_warn(x...) do { \
Joe Perches598d8092016-03-17 14:19:44 -0700279 pr_warn(x); \
Catalin Marinas5f790202011-09-28 12:17:03 +0100280 dump_stack(); \
Li Zefan8910ae892014-04-03 14:46:29 -0700281 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100282} while (0)
283
284/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300285 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100286 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100287 * tracing no longer available.
288 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100289#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100290 kmemleak_warn(x); \
291 kmemleak_disable(); \
292} while (0)
293
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700294#define warn_or_seq_printf(seq, fmt, ...) do { \
295 if (seq) \
296 seq_printf(seq, fmt, ##__VA_ARGS__); \
297 else \
298 pr_warn(fmt, ##__VA_ARGS__); \
299} while (0)
300
301static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type,
302 int rowsize, int groupsize, const void *buf,
303 size_t len, bool ascii)
304{
305 if (seq)
306 seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize,
307 buf, len, ascii);
308 else
309 print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type,
310 rowsize, groupsize, buf, len, ascii);
311}
312
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100313/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100314 * Printing of the objects hex dump to the seq file. The number of lines to be
315 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
316 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
317 * with the object->lock held.
318 */
319static void hex_dump_object(struct seq_file *seq,
320 struct kmemleak_object *object)
321{
322 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700323 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100324
325 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700326 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100327
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700328 warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700329 kasan_disable_current();
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700330 warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE,
331 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700332 kasan_enable_current();
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100333}
334
335/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100336 * Object colors, encoded with count and min_count:
337 * - white - orphan object, not enough references to it (count < min_count)
338 * - gray - not orphan, not marked as false positive (min_count == 0) or
339 * sufficient references to it (count >= min_count)
340 * - black - ignore, it doesn't contain references (e.g. text section)
341 * (min_count == -1). No function defined for this color.
342 * Newly created objects don't have any color assigned (object->count == -1)
343 * before the next memory scan when they become white.
344 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100345static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100346{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700347 return object->count != KMEMLEAK_BLACK &&
348 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100349}
350
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100351static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100352{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700353 return object->min_count != KMEMLEAK_BLACK &&
354 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100355}
356
357/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100358 * Objects are considered unreferenced only if their color is white, they have
359 * not be deleted and have a minimum age to avoid false positives caused by
360 * pointers temporarily stored in CPU registers.
361 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100362static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100363{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000364 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100365 time_before_eq(object->jiffies + jiffies_min_age,
366 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100367}
368
369/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100370 * Printing of the unreferenced objects information to the seq file. The
371 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100372 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100373static void print_unreferenced(struct seq_file *seq,
374 struct kmemleak_object *object)
375{
376 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000377 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100378
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700379 warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
Catalin Marinasbab4a342009-06-26 17:38:26 +0100380 object->pointer, object->size);
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700381 warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
Catalin Marinasfefdd332009-10-28 13:33:12 +0000382 object->comm, object->pid, object->jiffies,
383 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100384 hex_dump_object(seq, object);
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700385 warn_or_seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100386
387 for (i = 0; i < object->trace_len; i++) {
388 void *ptr = (void *)object->trace[i];
Vincent Whitchurch154221c2018-10-26 15:03:42 -0700389 warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100390 }
391}
392
393/*
394 * Print the kmemleak_object information. This function is used mainly for
395 * debugging special cases when kmemleak operations. It must be called with
396 * the object->lock held.
397 */
398static void dump_object_info(struct kmemleak_object *object)
399{
Joe Perchesae281062009-06-23 14:40:26 +0100400 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700401 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100402 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
403 object->comm, object->pid, object->jiffies);
404 pr_notice(" min_count = %d\n", object->min_count);
405 pr_notice(" count = %d\n", object->count);
Catalin Marinasf66abf02017-07-06 15:40:16 -0700406 pr_notice(" flags = 0x%x\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700407 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100408 pr_notice(" backtrace:\n");
Thomas Gleixner07984aa2019-04-25 11:45:01 +0200409 stack_trace_print(object->trace, object->trace_len, 4);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100410}
411
412/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700413 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100414 * tree based on a pointer value. If alias is 0, only values pointing to the
415 * beginning of the memory block are allowed. The kmemleak_lock must be held
416 * when calling this function.
417 */
418static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
419{
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700420 struct rb_node *rb = object_tree_root.rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100421
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700422 while (rb) {
423 struct kmemleak_object *object =
424 rb_entry(rb, struct kmemleak_object, rb_node);
425 if (ptr < object->pointer)
426 rb = object->rb_node.rb_left;
427 else if (object->pointer + object->size <= ptr)
428 rb = object->rb_node.rb_right;
429 else if (object->pointer == ptr || alias)
430 return object;
431 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100432 kmemleak_warn("Found object by alias at 0x%08lx\n",
433 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100434 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700435 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100436 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700437 }
438 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100439}
440
441/*
442 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
443 * that once an object's use_count reached 0, the RCU freeing was already
444 * registered and the object should no longer be used. This function must be
445 * called under the protection of rcu_read_lock().
446 */
447static int get_object(struct kmemleak_object *object)
448{
449 return atomic_inc_not_zero(&object->use_count);
450}
451
452/*
453 * RCU callback to free a kmemleak_object.
454 */
455static void free_object_rcu(struct rcu_head *rcu)
456{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800457 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100458 struct kmemleak_scan_area *area;
459 struct kmemleak_object *object =
460 container_of(rcu, struct kmemleak_object, rcu);
461
462 /*
463 * Once use_count is 0 (guaranteed by put_object), there is no other
464 * code accessing this object, hence no need for locking.
465 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800466 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
467 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100468 kmem_cache_free(scan_area_cache, area);
469 }
470 kmem_cache_free(object_cache, object);
471}
472
473/*
474 * Decrement the object use_count. Once the count is 0, free the object using
475 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
476 * delete_object() path, the delayed RCU freeing ensures that there is no
477 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
478 * is also possible.
479 */
480static void put_object(struct kmemleak_object *object)
481{
482 if (!atomic_dec_and_test(&object->use_count))
483 return;
484
485 /* should only get here after delete_object was called */
486 WARN_ON(object->flags & OBJECT_ALLOCATED);
487
488 call_rcu(&object->rcu, free_object_rcu);
489}
490
491/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700492 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100493 */
494static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
495{
496 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800497 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100498
499 rcu_read_lock();
500 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -0700501 object = lookup_object(ptr, alias);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100502 read_unlock_irqrestore(&kmemleak_lock, flags);
503
504 /* check whether the object is still available */
505 if (object && !get_object(object))
506 object = NULL;
507 rcu_read_unlock();
508
509 return object;
510}
511
512/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700513 * Look up an object in the object search tree and remove it from both
514 * object_tree_root and object_list. The returned object's use_count should be
515 * at least 1, as initially set by create_object().
516 */
517static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
518{
519 unsigned long flags;
520 struct kmemleak_object *object;
521
522 write_lock_irqsave(&kmemleak_lock, flags);
523 object = lookup_object(ptr, alias);
524 if (object) {
525 rb_erase(&object->rb_node, &object_tree_root);
526 list_del_rcu(&object->object_list);
527 }
528 write_unlock_irqrestore(&kmemleak_lock, flags);
529
530 return object;
531}
532
533/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100534 * Save stack trace to the given array of MAX_TRACE size.
535 */
536static int __save_stack_trace(unsigned long *trace)
537{
Thomas Gleixner07984aa2019-04-25 11:45:01 +0200538 return stack_trace_save(trace, MAX_TRACE, 2);
Catalin Marinasfd678962009-08-27 14:29:17 +0100539}
540
541/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100542 * Create the metadata (struct kmemleak_object) corresponding to an allocated
543 * memory block and add it to the object_list and object_tree_root.
544 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100545static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
546 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100547{
548 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700549 struct kmemleak_object *object, *parent;
550 struct rb_node **link, *rb_parent;
Andrey Konovalova2f77572019-02-20 22:19:16 -0800551 unsigned long untagged_ptr;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100552
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000553 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100554 if (!object) {
Joe Perches598d8092016-03-17 14:19:44 -0700555 pr_warn("Cannot allocate a kmemleak_object structure\n");
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000556 kmemleak_disable();
Catalin Marinasfd678962009-08-27 14:29:17 +0100557 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100558 }
559
560 INIT_LIST_HEAD(&object->object_list);
561 INIT_LIST_HEAD(&object->gray_list);
562 INIT_HLIST_HEAD(&object->area_list);
563 spin_lock_init(&object->lock);
564 atomic_set(&object->use_count, 1);
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000565 object->flags = OBJECT_ALLOCATED;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100566 object->pointer = ptr;
567 object->size = size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700568 object->excess_ref = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100569 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000570 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100571 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000572 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100573
574 /* task information */
575 if (in_irq()) {
576 object->pid = 0;
577 strncpy(object->comm, "hardirq", sizeof(object->comm));
Dmitry Vyukov6ef90562019-07-11 20:53:39 -0700578 } else if (in_serving_softirq()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100579 object->pid = 0;
580 strncpy(object->comm, "softirq", sizeof(object->comm));
581 } else {
582 object->pid = current->pid;
583 /*
584 * There is a small chance of a race with set_task_comm(),
585 * however using get_task_comm() here may cause locking
586 * dependency issues with current->alloc_lock. In the worst
587 * case, the command line is not correct.
588 */
589 strncpy(object->comm, current->comm, sizeof(object->comm));
590 }
591
592 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100593 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100594
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100595 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100596
Andrey Konovalova2f77572019-02-20 22:19:16 -0800597 untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
598 min_addr = min(min_addr, untagged_ptr);
599 max_addr = max(max_addr, untagged_ptr + size);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700600 link = &object_tree_root.rb_node;
601 rb_parent = NULL;
602 while (*link) {
603 rb_parent = *link;
604 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
605 if (ptr + size <= parent->pointer)
606 link = &parent->rb_node.rb_left;
607 else if (parent->pointer + parent->size <= ptr)
608 link = &parent->rb_node.rb_right;
609 else {
Joe Perches756a0252016-03-17 14:19:47 -0700610 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700611 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700612 /*
613 * No need for parent->lock here since "parent" cannot
614 * be freed while the kmemleak_lock is held.
615 */
616 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700617 kmem_cache_free(object_cache, object);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700618 object = NULL;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700619 goto out;
620 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100621 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700622 rb_link_node(&object->rb_node, rb_parent, link);
623 rb_insert_color(&object->rb_node, &object_tree_root);
624
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100625 list_add_tail_rcu(&object->object_list, &object_list);
626out:
627 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100628 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100629}
630
631/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700632 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100633 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100634static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100635{
636 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100637
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100638 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700639 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100640
641 /*
642 * Locking here also ensures that the corresponding memory block
643 * cannot be freed when it is being scanned.
644 */
645 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100646 object->flags &= ~OBJECT_ALLOCATED;
647 spin_unlock_irqrestore(&object->lock, flags);
648 put_object(object);
649}
650
651/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100652 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
653 * delete it.
654 */
655static void delete_object_full(unsigned long ptr)
656{
657 struct kmemleak_object *object;
658
Catalin Marinase781a9a2015-06-24 16:58:29 -0700659 object = find_and_remove_object(ptr, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100660 if (!object) {
661#ifdef DEBUG
662 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
663 ptr);
664#endif
665 return;
666 }
667 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100668}
669
670/*
671 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
672 * delete it. If the memory block is partially freed, the function may create
673 * additional metadata for the remaining parts of the block.
674 */
675static void delete_object_part(unsigned long ptr, size_t size)
676{
677 struct kmemleak_object *object;
678 unsigned long start, end;
679
Catalin Marinase781a9a2015-06-24 16:58:29 -0700680 object = find_and_remove_object(ptr, 1);
Catalin Marinas53238a62009-07-07 10:33:00 +0100681 if (!object) {
682#ifdef DEBUG
Joe Perches756a0252016-03-17 14:19:47 -0700683 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
684 ptr, size);
Catalin Marinas53238a62009-07-07 10:33:00 +0100685#endif
686 return;
687 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100688
689 /*
690 * Create one or two objects that may result from the memory block
691 * split. Note that partial freeing is only done by free_bootmem() and
692 * this happens before kmemleak_init() is called. The path below is
693 * only executed during early log recording in kmemleak_init(), so
694 * GFP_KERNEL is enough.
695 */
696 start = object->pointer;
697 end = object->pointer + object->size;
698 if (ptr > start)
699 create_object(start, ptr - start, object->min_count,
700 GFP_KERNEL);
701 if (ptr + size < end)
702 create_object(ptr + size, end - ptr - size, object->min_count,
703 GFP_KERNEL);
704
Catalin Marinase781a9a2015-06-24 16:58:29 -0700705 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100706}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700707
708static void __paint_it(struct kmemleak_object *object, int color)
709{
710 object->min_count = color;
711 if (color == KMEMLEAK_BLACK)
712 object->flags |= OBJECT_NO_SCAN;
713}
714
715static void paint_it(struct kmemleak_object *object, int color)
716{
717 unsigned long flags;
718
719 spin_lock_irqsave(&object->lock, flags);
720 __paint_it(object, color);
721 spin_unlock_irqrestore(&object->lock, flags);
722}
723
724static void paint_ptr(unsigned long ptr, int color)
725{
726 struct kmemleak_object *object;
727
728 object = find_and_get_object(ptr, 0);
729 if (!object) {
Joe Perches756a0252016-03-17 14:19:47 -0700730 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
731 ptr,
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700732 (color == KMEMLEAK_GREY) ? "Grey" :
733 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
734 return;
735 }
736 paint_it(object, color);
737 put_object(object);
738}
739
Catalin Marinas53238a62009-07-07 10:33:00 +0100740/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800741 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100742 * reported as a leak. This is used in general to mark a false positive.
743 */
744static void make_gray_object(unsigned long ptr)
745{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700746 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100747}
748
749/*
750 * Mark the object as black-colored so that it is ignored from scans and
751 * reporting.
752 */
753static void make_black_object(unsigned long ptr)
754{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700755 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100756}
757
758/*
759 * Add a scanning area to the object. If at least one such area is added,
760 * kmemleak will only scan these ranges rather than the whole memory block.
761 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000762static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100763{
764 unsigned long flags;
765 struct kmemleak_object *object;
766 struct kmemleak_scan_area *area;
767
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000768 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100769 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100770 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
771 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100772 return;
773 }
774
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000775 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100776 if (!area) {
Joe Perches598d8092016-03-17 14:19:44 -0700777 pr_warn("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100778 goto out;
779 }
780
781 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas7f88f882013-11-12 15:07:45 -0800782 if (size == SIZE_MAX) {
783 size = object->pointer + object->size - ptr;
784 } else if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100785 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100786 dump_object_info(object);
787 kmem_cache_free(scan_area_cache, area);
788 goto out_unlock;
789 }
790
791 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000792 area->start = ptr;
793 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100794
795 hlist_add_head(&area->node, &object->area_list);
796out_unlock:
797 spin_unlock_irqrestore(&object->lock, flags);
798out:
799 put_object(object);
800}
801
802/*
Catalin Marinas94f4a162017-07-06 15:40:22 -0700803 * Any surplus references (object already gray) to 'ptr' are passed to
804 * 'excess_ref'. This is used in the vmalloc() case where a pointer to
805 * vm_struct may be used as an alternative reference to the vmalloc'ed object
806 * (see free_thread_stack()).
807 */
808static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
809{
810 unsigned long flags;
811 struct kmemleak_object *object;
812
813 object = find_and_get_object(ptr, 0);
814 if (!object) {
815 kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
816 ptr);
817 return;
818 }
819
820 spin_lock_irqsave(&object->lock, flags);
821 object->excess_ref = excess_ref;
822 spin_unlock_irqrestore(&object->lock, flags);
823 put_object(object);
824}
825
826/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100827 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
828 * pointer. Such object will not be scanned by kmemleak but references to it
829 * are searched.
830 */
831static void object_no_scan(unsigned long ptr)
832{
833 unsigned long flags;
834 struct kmemleak_object *object;
835
836 object = find_and_get_object(ptr, 0);
837 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100838 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100839 return;
840 }
841
842 spin_lock_irqsave(&object->lock, flags);
843 object->flags |= OBJECT_NO_SCAN;
844 spin_unlock_irqrestore(&object->lock, flags);
845 put_object(object);
846}
847
848/*
849 * Log an early kmemleak_* call to the early_log buffer. These calls will be
850 * processed later once kmemleak is fully initialized.
851 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100852static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000853 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100854{
855 unsigned long flags;
856 struct early_log *log;
857
Li Zefan8910ae892014-04-03 14:46:29 -0700858 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +0100859 /* kmemleak stopped recording, just count the requests */
860 crt_early_log++;
861 return;
862 }
863
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100864 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Wang Kai21cd3a62015-09-08 15:03:41 -0700865 crt_early_log++;
Catalin Marinasa9d90582009-06-25 10:16:11 +0100866 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100867 return;
868 }
869
870 /*
871 * There is no need for locking since the kernel is still in UP mode
872 * at this stage. Disabling the IRQs is enough.
873 */
874 local_irq_save(flags);
875 log = &early_log[crt_early_log];
876 log->op_type = op_type;
877 log->ptr = ptr;
878 log->size = size;
879 log->min_count = min_count;
Catalin Marinas5f790202011-09-28 12:17:03 +0100880 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100881 crt_early_log++;
882 local_irq_restore(flags);
883}
884
885/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100886 * Log an early allocated block and populate the stack trace.
887 */
888static void early_alloc(struct early_log *log)
889{
890 struct kmemleak_object *object;
891 unsigned long flags;
892 int i;
893
Li Zefan8910ae892014-04-03 14:46:29 -0700894 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
Catalin Marinasfd678962009-08-27 14:29:17 +0100895 return;
896
897 /*
898 * RCU locking needed to ensure object is not freed via put_object().
899 */
900 rcu_read_lock();
901 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100902 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100903 if (!object)
904 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100905 spin_lock_irqsave(&object->lock, flags);
906 for (i = 0; i < log->trace_len; i++)
907 object->trace[i] = log->trace[i];
908 object->trace_len = log->trace_len;
909 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100910out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100911 rcu_read_unlock();
912}
913
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100914/*
915 * Log an early allocated block and populate the stack trace.
916 */
917static void early_alloc_percpu(struct early_log *log)
918{
919 unsigned int cpu;
920 const void __percpu *ptr = log->ptr;
921
922 for_each_possible_cpu(cpu) {
923 log->ptr = per_cpu_ptr(ptr, cpu);
924 early_alloc(log);
925 }
926}
927
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100928/**
929 * kmemleak_alloc - register a newly allocated object
930 * @ptr: pointer to beginning of the object
931 * @size: size of the object
932 * @min_count: minimum number of references to this object. If during memory
933 * scanning a number of references less than @min_count is found,
934 * the object is reported as a memory leak. If @min_count is 0,
935 * the object is never reported as a leak. If @min_count is -1,
936 * the object is ignored (not scanned and not reported as a leak)
937 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
938 *
939 * This function is called from the kernel allocators when a new object
Catalin Marinas94f4a162017-07-06 15:40:22 -0700940 * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100941 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100942void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
943 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100944{
945 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
946
Li Zefan8910ae892014-04-03 14:46:29 -0700947 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100948 create_object((unsigned long)ptr, size, min_count, gfp);
Li Zefan8910ae892014-04-03 14:46:29 -0700949 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000950 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100951}
952EXPORT_SYMBOL_GPL(kmemleak_alloc);
953
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100954/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100955 * kmemleak_alloc_percpu - register a newly allocated __percpu object
956 * @ptr: __percpu pointer to beginning of the object
957 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700958 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100959 *
960 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700961 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100962 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700963void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
964 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100965{
966 unsigned int cpu;
967
968 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
969
970 /*
971 * Percpu allocations are only scanned and not reported as leaks
972 * (min_count is set to 0).
973 */
Li Zefan8910ae892014-04-03 14:46:29 -0700974 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100975 for_each_possible_cpu(cpu)
976 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700977 size, 0, gfp);
Li Zefan8910ae892014-04-03 14:46:29 -0700978 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100979 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
980}
981EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
982
983/**
Catalin Marinas94f4a162017-07-06 15:40:22 -0700984 * kmemleak_vmalloc - register a newly vmalloc'ed object
985 * @area: pointer to vm_struct
986 * @size: size of the object
987 * @gfp: __vmalloc() flags used for kmemleak internal memory allocations
988 *
989 * This function is called from the vmalloc() kernel allocator when a new
990 * object (memory block) is allocated.
991 */
992void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
993{
994 pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
995
996 /*
997 * A min_count = 2 is needed because vm_struct contains a reference to
998 * the virtual address of the vmalloc'ed block.
999 */
1000 if (kmemleak_enabled) {
1001 create_object((unsigned long)area->addr, size, 2, gfp);
1002 object_set_excess_ref((unsigned long)area,
1003 (unsigned long)area->addr);
1004 } else if (kmemleak_early_log) {
1005 log_early(KMEMLEAK_ALLOC, area->addr, size, 2);
1006 /* reusing early_log.size for storing area->addr */
1007 log_early(KMEMLEAK_SET_EXCESS_REF,
1008 area, (unsigned long)area->addr, 0);
1009 }
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);
Li Zefan8910ae892014-04-03 14:46:29 -07001026 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001027 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001028}
1029EXPORT_SYMBOL_GPL(kmemleak_free);
1030
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001031/**
1032 * kmemleak_free_part - partially unregister a previously registered object
1033 * @ptr: pointer to the beginning or inside the object. This also
1034 * represents the start of the range to be freed
1035 * @size: size to be unregistered
1036 *
1037 * This function is called when only a part of a memory block is freed
1038 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +01001039 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001040void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +01001041{
1042 pr_debug("%s(0x%p)\n", __func__, ptr);
1043
Li Zefan8910ae892014-04-03 14:46:29 -07001044 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001045 delete_object_part((unsigned long)ptr, size);
Li Zefan8910ae892014-04-03 14:46:29 -07001046 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001047 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +01001048}
1049EXPORT_SYMBOL_GPL(kmemleak_free_part);
1050
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001051/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001052 * kmemleak_free_percpu - unregister a previously registered __percpu object
1053 * @ptr: __percpu pointer to beginning of the object
1054 *
1055 * This function is called from the kernel percpu allocator when an object
1056 * (memory block) is freed (free_percpu).
1057 */
1058void __ref kmemleak_free_percpu(const void __percpu *ptr)
1059{
1060 unsigned int cpu;
1061
1062 pr_debug("%s(0x%p)\n", __func__, ptr);
1063
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001064 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001065 for_each_possible_cpu(cpu)
1066 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1067 cpu));
Li Zefan8910ae892014-04-03 14:46:29 -07001068 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001069 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1070}
1071EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1072
1073/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001074 * kmemleak_update_trace - update object allocation stack trace
1075 * @ptr: pointer to beginning of the object
1076 *
1077 * Override the object allocation stack trace for cases where the actual
1078 * allocation place is not always useful.
1079 */
1080void __ref kmemleak_update_trace(const void *ptr)
1081{
1082 struct kmemleak_object *object;
1083 unsigned long flags;
1084
1085 pr_debug("%s(0x%p)\n", __func__, ptr);
1086
1087 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1088 return;
1089
1090 object = find_and_get_object((unsigned long)ptr, 1);
1091 if (!object) {
1092#ifdef DEBUG
1093 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1094 ptr);
1095#endif
1096 return;
1097 }
1098
1099 spin_lock_irqsave(&object->lock, flags);
1100 object->trace_len = __save_stack_trace(object->trace);
1101 spin_unlock_irqrestore(&object->lock, flags);
1102
1103 put_object(object);
1104}
1105EXPORT_SYMBOL(kmemleak_update_trace);
1106
1107/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001108 * kmemleak_not_leak - mark an allocated object as false positive
1109 * @ptr: pointer to beginning of the object
1110 *
1111 * Calling this function on an object will cause the memory block to no longer
1112 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001113 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001114void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001115{
1116 pr_debug("%s(0x%p)\n", __func__, ptr);
1117
Li Zefan8910ae892014-04-03 14:46:29 -07001118 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001119 make_gray_object((unsigned long)ptr);
Li Zefan8910ae892014-04-03 14:46:29 -07001120 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001121 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001122}
1123EXPORT_SYMBOL(kmemleak_not_leak);
1124
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001125/**
1126 * kmemleak_ignore - ignore an allocated object
1127 * @ptr: pointer to beginning of the object
1128 *
1129 * Calling this function on an object will cause the memory block to be
1130 * ignored (not scanned and not reported as a leak). This is usually done when
1131 * it is known that the corresponding block is not a leak and does not contain
1132 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001133 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001134void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001135{
1136 pr_debug("%s(0x%p)\n", __func__, ptr);
1137
Li Zefan8910ae892014-04-03 14:46:29 -07001138 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001139 make_black_object((unsigned long)ptr);
Li Zefan8910ae892014-04-03 14:46:29 -07001140 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001141 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001142}
1143EXPORT_SYMBOL(kmemleak_ignore);
1144
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001145/**
1146 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1147 * @ptr: pointer to beginning or inside the object. This also
1148 * represents the start of the scan area
1149 * @size: size of the scan area
1150 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1151 *
1152 * This function is used when it is known that only certain parts of an object
1153 * contain references to other objects. Kmemleak will only scan these areas
1154 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001155 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001156void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001157{
1158 pr_debug("%s(0x%p)\n", __func__, ptr);
1159
Li Zefan8910ae892014-04-03 14:46:29 -07001160 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001161 add_scan_area((unsigned long)ptr, size, gfp);
Li Zefan8910ae892014-04-03 14:46:29 -07001162 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001163 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001164}
1165EXPORT_SYMBOL(kmemleak_scan_area);
1166
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001167/**
1168 * kmemleak_no_scan - do not scan an allocated object
1169 * @ptr: pointer to beginning of the object
1170 *
1171 * This function notifies kmemleak not to scan the given memory block. Useful
1172 * in situations where it is known that the given object does not contain any
1173 * references to other objects. Kmemleak will not scan such objects reducing
1174 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001175 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001176void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001177{
1178 pr_debug("%s(0x%p)\n", __func__, ptr);
1179
Li Zefan8910ae892014-04-03 14:46:29 -07001180 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001181 object_no_scan((unsigned long)ptr);
Li Zefan8910ae892014-04-03 14:46:29 -07001182 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001183 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001184}
1185EXPORT_SYMBOL(kmemleak_no_scan);
1186
Catalin Marinas9099dae2016-10-11 13:55:11 -07001187/**
1188 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1189 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001190 * @phys: physical address of the object
1191 * @size: size of the object
1192 * @min_count: minimum number of references to this object.
1193 * See kmemleak_alloc()
1194 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
Catalin Marinas9099dae2016-10-11 13:55:11 -07001195 */
1196void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1197 gfp_t gfp)
1198{
1199 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1200 kmemleak_alloc(__va(phys), size, min_count, gfp);
1201}
1202EXPORT_SYMBOL(kmemleak_alloc_phys);
1203
1204/**
1205 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1206 * physical address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001207 * @phys: physical address if the beginning or inside an object. This
1208 * also represents the start of the range to be freed
1209 * @size: size to be unregistered
Catalin Marinas9099dae2016-10-11 13:55:11 -07001210 */
1211void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1212{
1213 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1214 kmemleak_free_part(__va(phys), size);
1215}
1216EXPORT_SYMBOL(kmemleak_free_part_phys);
1217
1218/**
1219 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1220 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001221 * @phys: physical address of the object
Catalin Marinas9099dae2016-10-11 13:55:11 -07001222 */
1223void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1224{
1225 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1226 kmemleak_not_leak(__va(phys));
1227}
1228EXPORT_SYMBOL(kmemleak_not_leak_phys);
1229
1230/**
1231 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1232 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001233 * @phys: physical address of the object
Catalin Marinas9099dae2016-10-11 13:55:11 -07001234 */
1235void __ref kmemleak_ignore_phys(phys_addr_t phys)
1236{
1237 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1238 kmemleak_ignore(__va(phys));
1239}
1240EXPORT_SYMBOL(kmemleak_ignore_phys);
1241
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001242/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001243 * Update an object's checksum and return true if it was modified.
1244 */
1245static bool update_checksum(struct kmemleak_object *object)
1246{
1247 u32 old_csum = object->checksum;
1248
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001249 kasan_disable_current();
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001250 object->checksum = crc32(0, (void *)object->pointer, object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001251 kasan_enable_current();
1252
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001253 return object->checksum != old_csum;
1254}
1255
1256/*
Catalin Marinas04f70d12017-07-06 15:40:19 -07001257 * Update an object's references. object->lock must be held by the caller.
1258 */
1259static void update_refs(struct kmemleak_object *object)
1260{
1261 if (!color_white(object)) {
1262 /* non-orphan, ignored or new */
1263 return;
1264 }
1265
1266 /*
1267 * Increase the object's reference count (number of pointers to the
1268 * memory block). If this count reaches the required minimum, the
1269 * object's color will become gray and it will be added to the
1270 * gray_list.
1271 */
1272 object->count++;
1273 if (color_gray(object)) {
1274 /* put_object() called when removing from gray_list */
1275 WARN_ON(!get_object(object));
1276 list_add_tail(&object->gray_list, &gray_list);
1277 }
1278}
1279
1280/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001281 * Memory scanning is a long process and it needs to be interruptable. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001282 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001283 */
1284static int scan_should_stop(void)
1285{
Li Zefan8910ae892014-04-03 14:46:29 -07001286 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001287 return 1;
1288
1289 /*
1290 * This function may be called from either process or kthread context,
1291 * hence the need to check for both stop conditions.
1292 */
1293 if (current->mm)
1294 return signal_pending(current);
1295 else
1296 return kthread_should_stop();
1297
1298 return 0;
1299}
1300
1301/*
1302 * Scan a memory block (exclusive range) for valid pointers and add those
1303 * found to the gray list.
1304 */
1305static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001306 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001307{
1308 unsigned long *ptr;
1309 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1310 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001311 unsigned long flags;
Andrey Konovalova2f77572019-02-20 22:19:16 -08001312 unsigned long untagged_ptr;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001313
Catalin Marinas93ada572015-06-24 16:58:37 -07001314 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001315 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001316 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001317 unsigned long pointer;
Catalin Marinas94f4a162017-07-06 15:40:22 -07001318 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001319
1320 if (scan_should_stop())
1321 break;
1322
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001323 kasan_disable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001324 pointer = *ptr;
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001325 kasan_enable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001326
Andrey Konovalova2f77572019-02-20 22:19:16 -08001327 untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);
1328 if (untagged_ptr < min_addr || untagged_ptr >= max_addr)
Catalin Marinas93ada572015-06-24 16:58:37 -07001329 continue;
1330
1331 /*
1332 * No need for get_object() here since we hold kmemleak_lock.
1333 * object->use_count cannot be dropped to 0 while the object
1334 * is still present in object_tree_root and object_list
1335 * (with updates protected by kmemleak_lock).
1336 */
1337 object = lookup_object(pointer, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001338 if (!object)
1339 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001340 if (object == scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001341 /* self referenced, ignore */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001342 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001343
1344 /*
1345 * Avoid the lockdep recursive warning on object->lock being
1346 * previously acquired in scan_object(). These locks are
1347 * enclosed by scan_mutex.
1348 */
Catalin Marinas93ada572015-06-24 16:58:37 -07001349 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001350 /* only pass surplus references (object already gray) */
1351 if (color_gray(object)) {
1352 excess_ref = object->excess_ref;
1353 /* no need for update_refs() if object already gray */
1354 } else {
1355 excess_ref = 0;
1356 update_refs(object);
1357 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001358 spin_unlock(&object->lock);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001359
1360 if (excess_ref) {
1361 object = lookup_object(excess_ref, 0);
1362 if (!object)
1363 continue;
1364 if (object == scanned)
1365 /* circular reference, ignore */
1366 continue;
1367 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
1368 update_refs(object);
1369 spin_unlock(&object->lock);
1370 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001371 }
1372 read_unlock_irqrestore(&kmemleak_lock, flags);
1373}
Catalin Marinas0587da42009-10-28 13:33:11 +00001374
Catalin Marinas93ada572015-06-24 16:58:37 -07001375/*
1376 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1377 */
Arnd Bergmanndce5b0b2019-04-18 17:50:48 -07001378#ifdef CONFIG_SMP
Catalin Marinas93ada572015-06-24 16:58:37 -07001379static void scan_large_block(void *start, void *end)
1380{
1381 void *next;
1382
1383 while (start < end) {
1384 next = min(start + MAX_SCAN_SIZE, end);
1385 scan_block(start, next, NULL);
1386 start = next;
1387 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001388 }
1389}
Arnd Bergmanndce5b0b2019-04-18 17:50:48 -07001390#endif
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001391
1392/*
1393 * Scan a memory block corresponding to a kmemleak_object. A condition is
1394 * that object->use_count >= 1.
1395 */
1396static void scan_object(struct kmemleak_object *object)
1397{
1398 struct kmemleak_scan_area *area;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001399 unsigned long flags;
1400
1401 /*
Uwe Kleine-König21ae2952009-10-07 15:21:09 +02001402 * Once the object->lock is acquired, the corresponding memory block
1403 * cannot be freed (the same lock is acquired in delete_object).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001404 */
1405 spin_lock_irqsave(&object->lock, flags);
1406 if (object->flags & OBJECT_NO_SCAN)
1407 goto out;
1408 if (!(object->flags & OBJECT_ALLOCATED))
1409 /* already freed object */
1410 goto out;
Catalin Marinasaf986032009-08-27 14:29:12 +01001411 if (hlist_empty(&object->area_list)) {
1412 void *start = (void *)object->pointer;
1413 void *end = (void *)(object->pointer + object->size);
Catalin Marinas93ada572015-06-24 16:58:37 -07001414 void *next;
Catalin Marinasaf986032009-08-27 14:29:12 +01001415
Catalin Marinas93ada572015-06-24 16:58:37 -07001416 do {
1417 next = min(start + MAX_SCAN_SIZE, end);
1418 scan_block(start, next, object);
1419
1420 start = next;
1421 if (start >= end)
1422 break;
Catalin Marinasaf986032009-08-27 14:29:12 +01001423
1424 spin_unlock_irqrestore(&object->lock, flags);
1425 cond_resched();
1426 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001427 } while (object->flags & OBJECT_ALLOCATED);
Catalin Marinasaf986032009-08-27 14:29:12 +01001428 } else
Sasha Levinb67bfe02013-02-27 17:06:00 -08001429 hlist_for_each_entry(area, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001430 scan_block((void *)area->start,
1431 (void *)(area->start + area->size),
Catalin Marinas93ada572015-06-24 16:58:37 -07001432 object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001433out:
1434 spin_unlock_irqrestore(&object->lock, flags);
1435}
1436
1437/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001438 * Scan the objects already referenced (gray objects). More objects will be
1439 * referenced and, if there are no memory leaks, all the objects are scanned.
1440 */
1441static void scan_gray_list(void)
1442{
1443 struct kmemleak_object *object, *tmp;
1444
1445 /*
1446 * The list traversal is safe for both tail additions and removals
1447 * from inside the loop. The kmemleak objects cannot be freed from
1448 * outside the loop because their use_count was incremented.
1449 */
1450 object = list_entry(gray_list.next, typeof(*object), gray_list);
1451 while (&object->gray_list != &gray_list) {
1452 cond_resched();
1453
1454 /* may add new objects to the list */
1455 if (!scan_should_stop())
1456 scan_object(object);
1457
1458 tmp = list_entry(object->gray_list.next, typeof(*object),
1459 gray_list);
1460
1461 /* remove the object from the list and release it */
1462 list_del(&object->gray_list);
1463 put_object(object);
1464
1465 object = tmp;
1466 }
1467 WARN_ON(!list_empty(&gray_list));
1468}
1469
1470/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001471 * Scan data sections and all the referenced memory blocks allocated via the
1472 * kernel's standard allocators. This function must be called with the
1473 * scan_mutex held.
1474 */
1475static void kmemleak_scan(void)
1476{
1477 unsigned long flags;
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001478 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001479 int i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001480 int new_leaks = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001481
Catalin Marinasacf49682009-06-26 17:38:29 +01001482 jiffies_last_scan = jiffies;
1483
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001484 /* prepare the kmemleak_object's */
1485 rcu_read_lock();
1486 list_for_each_entry_rcu(object, &object_list, object_list) {
1487 spin_lock_irqsave(&object->lock, flags);
1488#ifdef DEBUG
1489 /*
1490 * With a few exceptions there should be a maximum of
1491 * 1 reference to any object at this point.
1492 */
1493 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001494 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001495 atomic_read(&object->use_count));
1496 dump_object_info(object);
1497 }
1498#endif
1499 /* reset the reference count (whiten the object) */
1500 object->count = 0;
1501 if (color_gray(object) && get_object(object))
1502 list_add_tail(&object->gray_list, &gray_list);
1503
1504 spin_unlock_irqrestore(&object->lock, flags);
1505 }
1506 rcu_read_unlock();
1507
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001508#ifdef CONFIG_SMP
1509 /* per-cpu sections scanning */
1510 for_each_possible_cpu(i)
Catalin Marinas93ada572015-06-24 16:58:37 -07001511 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1512 __per_cpu_end + per_cpu_offset(i));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001513#endif
1514
1515 /*
Laura Abbott029aeff2011-11-15 23:49:09 +00001516 * Struct page scanning for each node.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001517 */
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001518 get_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001519 for_each_online_node(i) {
Cody P Schafer108bcc92013-02-22 16:35:23 -08001520 unsigned long start_pfn = node_start_pfn(i);
1521 unsigned long end_pfn = node_end_pfn(i);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001522 unsigned long pfn;
1523
1524 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
Oscar Salvador9f1eb382018-12-28 00:37:57 -08001525 struct page *page = pfn_to_online_page(pfn);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001526
Oscar Salvador9f1eb382018-12-28 00:37:57 -08001527 if (!page)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001528 continue;
Oscar Salvador9f1eb382018-12-28 00:37:57 -08001529
1530 /* only scan pages belonging to this node */
1531 if (page_to_nid(page) != i)
1532 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001533 /* only scan if page is in use */
1534 if (page_count(page) == 0)
1535 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001536 scan_block(page, page + 1, NULL);
Andrew Morton13ab183d2017-12-14 15:32:31 -08001537 if (!(pfn & 63))
Yisheng Xiebde5f6b2017-11-29 16:11:08 -08001538 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001539 }
1540 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001541 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001542
1543 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001544 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001545 */
1546 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001547 struct task_struct *p, *g;
1548
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001549 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001550 do_each_thread(g, p) {
Catalin Marinas37df49f2016-10-27 17:46:47 -07001551 void *stack = try_get_task_stack(p);
1552 if (stack) {
1553 scan_block(stack, stack + THREAD_SIZE, NULL);
1554 put_task_stack(p);
1555 }
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001556 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001557 read_unlock(&tasklist_lock);
1558 }
1559
1560 /*
1561 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001562 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001563 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001564 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001565
1566 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001567 * Check for new or unreferenced objects modified since the previous
1568 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001569 */
1570 rcu_read_lock();
1571 list_for_each_entry_rcu(object, &object_list, object_list) {
1572 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001573 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1574 && update_checksum(object) && get_object(object)) {
1575 /* color it gray temporarily */
1576 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001577 list_add_tail(&object->gray_list, &gray_list);
1578 }
1579 spin_unlock_irqrestore(&object->lock, flags);
1580 }
1581 rcu_read_unlock();
1582
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001583 /*
1584 * Re-scan the gray list for modified unreferenced objects.
1585 */
1586 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001587
1588 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001589 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001590 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001591 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001592 return;
1593
1594 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001595 * Scanning result reporting.
1596 */
1597 rcu_read_lock();
1598 list_for_each_entry_rcu(object, &object_list, object_list) {
1599 spin_lock_irqsave(&object->lock, flags);
1600 if (unreferenced_object(object) &&
1601 !(object->flags & OBJECT_REPORTED)) {
1602 object->flags |= OBJECT_REPORTED;
Vincent Whitchurch154221c2018-10-26 15:03:42 -07001603
1604 if (kmemleak_verbose)
1605 print_unreferenced(NULL, object);
1606
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001607 new_leaks++;
1608 }
1609 spin_unlock_irqrestore(&object->lock, flags);
1610 }
1611 rcu_read_unlock();
1612
Li Zefandc9b3f42014-04-03 14:46:26 -07001613 if (new_leaks) {
1614 kmemleak_found_leaks = true;
1615
Joe Perches756a0252016-03-17 14:19:47 -07001616 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1617 new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001618 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001619
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001620}
1621
1622/*
1623 * Thread function performing automatic memory scanning. Unreferenced objects
1624 * at the end of a memory scan are reported but only the first time.
1625 */
1626static int kmemleak_scan_thread(void *arg)
1627{
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -08001628 static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001629
Joe Perchesae281062009-06-23 14:40:26 +01001630 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001631 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001632
1633 /*
1634 * Wait before the first scan to allow the system to fully initialize.
1635 */
1636 if (first_run) {
Vegard Nossum98c42d92016-07-28 15:48:32 -07001637 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001638 first_run = 0;
Vegard Nossum98c42d92016-07-28 15:48:32 -07001639 while (timeout && !kthread_should_stop())
1640 timeout = schedule_timeout_interruptible(timeout);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001641 }
1642
1643 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001644 signed long timeout = jiffies_scan_wait;
1645
1646 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001647 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001648 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001649
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001650 /* wait before the next scan */
1651 while (timeout && !kthread_should_stop())
1652 timeout = schedule_timeout_interruptible(timeout);
1653 }
1654
Joe Perchesae281062009-06-23 14:40:26 +01001655 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001656
1657 return 0;
1658}
1659
1660/*
1661 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001662 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001663 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001664static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001665{
1666 if (scan_thread)
1667 return;
1668 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1669 if (IS_ERR(scan_thread)) {
Joe Perches598d8092016-03-17 14:19:44 -07001670 pr_warn("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001671 scan_thread = NULL;
1672 }
1673}
1674
1675/*
Vinayak Menon914b6df2018-03-28 16:01:16 -07001676 * Stop the automatic memory scanning thread.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001677 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001678static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001679{
1680 if (scan_thread) {
1681 kthread_stop(scan_thread);
1682 scan_thread = NULL;
1683 }
1684}
1685
1686/*
1687 * Iterate over the object_list and return the first valid object at or after
1688 * the required position with its use_count incremented. The function triggers
1689 * a memory scanning when the pos argument points to the first position.
1690 */
1691static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1692{
1693 struct kmemleak_object *object;
1694 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001695 int err;
1696
1697 err = mutex_lock_interruptible(&scan_mutex);
1698 if (err < 0)
1699 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001700
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001701 rcu_read_lock();
1702 list_for_each_entry_rcu(object, &object_list, object_list) {
1703 if (n-- > 0)
1704 continue;
1705 if (get_object(object))
1706 goto out;
1707 }
1708 object = NULL;
1709out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001710 return object;
1711}
1712
1713/*
1714 * Return the next object in the object_list. The function decrements the
1715 * use_count of the previous object and increases that of the next one.
1716 */
1717static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1718{
1719 struct kmemleak_object *prev_obj = v;
1720 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001721 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001722
1723 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001724
Michael Wang58fac092012-08-17 12:33:34 +08001725 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001726 if (get_object(obj)) {
1727 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001728 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001729 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001730 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001731
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001732 put_object(prev_obj);
1733 return next_obj;
1734}
1735
1736/*
1737 * Decrement the use_count of the last object required, if any.
1738 */
1739static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1740{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001741 if (!IS_ERR(v)) {
1742 /*
1743 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1744 * waiting was interrupted, so only release it if !IS_ERR.
1745 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001746 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001747 mutex_unlock(&scan_mutex);
1748 if (v)
1749 put_object(v);
1750 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001751}
1752
1753/*
1754 * Print the information for an unreferenced object to the seq file.
1755 */
1756static int kmemleak_seq_show(struct seq_file *seq, void *v)
1757{
1758 struct kmemleak_object *object = v;
1759 unsigned long flags;
1760
1761 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001762 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001763 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001764 spin_unlock_irqrestore(&object->lock, flags);
1765 return 0;
1766}
1767
1768static const struct seq_operations kmemleak_seq_ops = {
1769 .start = kmemleak_seq_start,
1770 .next = kmemleak_seq_next,
1771 .stop = kmemleak_seq_stop,
1772 .show = kmemleak_seq_show,
1773};
1774
1775static int kmemleak_open(struct inode *inode, struct file *file)
1776{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001777 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001778}
1779
Catalin Marinas189d84e2009-08-27 14:29:15 +01001780static int dump_str_object_info(const char *str)
1781{
1782 unsigned long flags;
1783 struct kmemleak_object *object;
1784 unsigned long addr;
1785
Abhijit Pawardc053732012-12-18 14:23:27 -08001786 if (kstrtoul(str, 0, &addr))
1787 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001788 object = find_and_get_object(addr, 0);
1789 if (!object) {
1790 pr_info("Unknown object at 0x%08lx\n", addr);
1791 return -EINVAL;
1792 }
1793
1794 spin_lock_irqsave(&object->lock, flags);
1795 dump_object_info(object);
1796 spin_unlock_irqrestore(&object->lock, flags);
1797
1798 put_object(object);
1799 return 0;
1800}
1801
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001802/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001803 * We use grey instead of black to ensure we can do future scans on the same
1804 * objects. If we did not do future scans these black objects could
1805 * potentially contain references to newly allocated objects in the future and
1806 * we'd end up with false positives.
1807 */
1808static void kmemleak_clear(void)
1809{
1810 struct kmemleak_object *object;
1811 unsigned long flags;
1812
1813 rcu_read_lock();
1814 list_for_each_entry_rcu(object, &object_list, object_list) {
1815 spin_lock_irqsave(&object->lock, flags);
1816 if ((object->flags & OBJECT_REPORTED) &&
1817 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001818 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001819 spin_unlock_irqrestore(&object->lock, flags);
1820 }
1821 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001822
1823 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001824}
1825
Li Zefanc89da702014-04-03 14:46:27 -07001826static void __kmemleak_do_cleanup(void);
1827
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001828/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001829 * File write operation to configure kmemleak at run-time. The following
1830 * commands can be written to the /sys/kernel/debug/kmemleak file:
1831 * off - disable kmemleak (irreversible)
1832 * stack=on - enable the task stacks scanning
1833 * stack=off - disable the tasks stacks scanning
1834 * scan=on - start the automatic memory scanning thread
1835 * scan=off - stop the automatic memory scanning thread
1836 * scan=... - set the automatic memory scanning period in seconds (0 to
1837 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001838 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001839 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001840 * grey to ignore printing them, or free all kmemleak objects
1841 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001842 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001843 */
1844static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1845 size_t size, loff_t *ppos)
1846{
1847 char buf[64];
1848 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001849 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001850
1851 buf_size = min(size, (sizeof(buf) - 1));
1852 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1853 return -EFAULT;
1854 buf[buf_size] = 0;
1855
Catalin Marinasb87324d2009-07-07 10:32:58 +01001856 ret = mutex_lock_interruptible(&scan_mutex);
1857 if (ret < 0)
1858 return ret;
1859
Li Zefanc89da702014-04-03 14:46:27 -07001860 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae892014-04-03 14:46:29 -07001861 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001862 kmemleak_clear();
1863 else
1864 __kmemleak_do_cleanup();
1865 goto out;
1866 }
1867
Li Zefan8910ae892014-04-03 14:46:29 -07001868 if (!kmemleak_enabled) {
André Almeida4e4dfce2019-07-11 20:53:43 -07001869 ret = -EPERM;
Li Zefanc89da702014-04-03 14:46:27 -07001870 goto out;
1871 }
1872
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001873 if (strncmp(buf, "off", 3) == 0)
1874 kmemleak_disable();
1875 else if (strncmp(buf, "stack=on", 8) == 0)
1876 kmemleak_stack_scan = 1;
1877 else if (strncmp(buf, "stack=off", 9) == 0)
1878 kmemleak_stack_scan = 0;
1879 else if (strncmp(buf, "scan=on", 7) == 0)
1880 start_scan_thread();
1881 else if (strncmp(buf, "scan=off", 8) == 0)
1882 stop_scan_thread();
1883 else if (strncmp(buf, "scan=", 5) == 0) {
1884 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001885
Jingoo Han3dbb95f2013-09-11 14:20:25 -07001886 ret = kstrtoul(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001887 if (ret < 0)
1888 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001889 stop_scan_thread();
1890 if (secs) {
1891 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1892 start_scan_thread();
1893 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001894 } else if (strncmp(buf, "scan", 4) == 0)
1895 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001896 else if (strncmp(buf, "dump=", 5) == 0)
1897 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001898 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001899 ret = -EINVAL;
1900
1901out:
1902 mutex_unlock(&scan_mutex);
1903 if (ret < 0)
1904 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001905
1906 /* ignore the rest of the buffer, only one command at a time */
1907 *ppos += size;
1908 return size;
1909}
1910
1911static const struct file_operations kmemleak_fops = {
1912 .owner = THIS_MODULE,
1913 .open = kmemleak_open,
1914 .read = seq_read,
1915 .write = kmemleak_write,
1916 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001917 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001918};
1919
Li Zefanc89da702014-04-03 14:46:27 -07001920static void __kmemleak_do_cleanup(void)
1921{
1922 struct kmemleak_object *object;
1923
1924 rcu_read_lock();
1925 list_for_each_entry_rcu(object, &object_list, object_list)
1926 delete_object_full(object->pointer);
1927 rcu_read_unlock();
1928}
1929
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001930/*
Catalin Marinas74341702011-09-29 11:50:07 +01001931 * Stop the memory scanning thread and free the kmemleak internal objects if
1932 * no previous scan thread (otherwise, kmemleak may still have some useful
1933 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001934 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001935static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001936{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001937 stop_scan_thread();
1938
Vinayak Menon914b6df2018-03-28 16:01:16 -07001939 mutex_lock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001940 /*
Vinayak Menon914b6df2018-03-28 16:01:16 -07001941 * Once it is made sure that kmemleak_scan has stopped, it is safe to no
1942 * longer track object freeing. Ordering of the scan thread stopping and
1943 * the memory accesses below is guaranteed by the kthread_stop()
1944 * function.
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001945 */
1946 kmemleak_free_enabled = 0;
Vinayak Menon914b6df2018-03-28 16:01:16 -07001947 mutex_unlock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001948
Li Zefanc89da702014-04-03 14:46:27 -07001949 if (!kmemleak_found_leaks)
1950 __kmemleak_do_cleanup();
1951 else
Joe Perches756a0252016-03-17 14:19:47 -07001952 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 +01001953}
1954
Catalin Marinas179a8102009-09-07 10:14:42 +01001955static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001956
1957/*
1958 * Disable kmemleak. No memory allocation/freeing will be traced once this
1959 * function is called. Disabling kmemleak is an irreversible operation.
1960 */
1961static void kmemleak_disable(void)
1962{
1963 /* atomically check whether it was already invoked */
Li Zefan8910ae892014-04-03 14:46:29 -07001964 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001965 return;
1966
1967 /* stop any memory operation tracing */
Li Zefan8910ae892014-04-03 14:46:29 -07001968 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001969
1970 /* check whether it is too early for a kernel thread */
Li Zefan8910ae892014-04-03 14:46:29 -07001971 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01001972 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001973 else
1974 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001975
1976 pr_info("Kernel memory leak detector disabled\n");
1977}
1978
1979/*
1980 * Allow boot-time kmemleak disabling (enabled by default).
1981 */
Dou Liyang8bd30c12018-04-05 16:23:46 -07001982static int __init kmemleak_boot_config(char *str)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001983{
1984 if (!str)
1985 return -EINVAL;
1986 if (strcmp(str, "off") == 0)
1987 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01001988 else if (strcmp(str, "on") == 0)
1989 kmemleak_skip_disable = 1;
1990 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001991 return -EINVAL;
1992 return 0;
1993}
1994early_param("kmemleak", kmemleak_boot_config);
1995
Catalin Marinas5f790202011-09-28 12:17:03 +01001996static void __init print_log_trace(struct early_log *log)
1997{
Catalin Marinas5f790202011-09-28 12:17:03 +01001998 pr_notice("Early log backtrace:\n");
Thomas Gleixner07984aa2019-04-25 11:45:01 +02001999 stack_trace_print(log->trace, log->trace_len, 2);
Catalin Marinas5f790202011-09-28 12:17:03 +01002000}
2001
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002002/*
Catalin Marinas20301172009-06-17 18:29:04 +01002003 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002004 */
2005void __init kmemleak_init(void)
2006{
2007 int i;
2008 unsigned long flags;
2009
Jason Baronab0155a2010-07-19 11:54:17 +01002010#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
2011 if (!kmemleak_skip_disable) {
Catalin Marinas3551a922014-05-09 15:36:59 -07002012 kmemleak_early_log = 0;
Jason Baronab0155a2010-07-19 11:54:17 +01002013 kmemleak_disable();
2014 return;
2015 }
2016#endif
2017
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002018 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
2019 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
2020
2021 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
2022 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002023
Wang Kai21cd3a62015-09-08 15:03:41 -07002024 if (crt_early_log > ARRAY_SIZE(early_log))
Joe Perches598d8092016-03-17 14:19:44 -07002025 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
2026 crt_early_log);
Catalin Marinasb6693002011-09-28 17:22:56 +01002027
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002028 /* the kernel is still in UP mode, so disabling the IRQs is enough */
2029 local_irq_save(flags);
Catalin Marinas3551a922014-05-09 15:36:59 -07002030 kmemleak_early_log = 0;
Li Zefan8910ae892014-04-03 14:46:29 -07002031 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +01002032 local_irq_restore(flags);
2033 return;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002034 } else {
Li Zefan8910ae892014-04-03 14:46:29 -07002035 kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002036 kmemleak_free_enabled = 1;
2037 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002038 local_irq_restore(flags);
2039
Catalin Marinas298a32b2019-04-05 18:38:49 -07002040 /* register the data/bss sections */
2041 create_object((unsigned long)_sdata, _edata - _sdata,
2042 KMEMLEAK_GREY, GFP_ATOMIC);
2043 create_object((unsigned long)__bss_start, __bss_stop - __bss_start,
2044 KMEMLEAK_GREY, GFP_ATOMIC);
2045 /* only register .data..ro_after_init if not within .data */
2046 if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
2047 create_object((unsigned long)__start_ro_after_init,
2048 __end_ro_after_init - __start_ro_after_init,
2049 KMEMLEAK_GREY, GFP_ATOMIC);
2050
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002051 /*
2052 * This is the point where tracking allocations is safe. Automatic
2053 * scanning is started during the late initcall. Add the early logged
2054 * callbacks to the kmemleak infrastructure.
2055 */
2056 for (i = 0; i < crt_early_log; i++) {
2057 struct early_log *log = &early_log[i];
2058
2059 switch (log->op_type) {
2060 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01002061 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002062 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002063 case KMEMLEAK_ALLOC_PERCPU:
2064 early_alloc_percpu(log);
2065 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002066 case KMEMLEAK_FREE:
2067 kmemleak_free(log->ptr);
2068 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01002069 case KMEMLEAK_FREE_PART:
2070 kmemleak_free_part(log->ptr, log->size);
2071 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002072 case KMEMLEAK_FREE_PERCPU:
2073 kmemleak_free_percpu(log->ptr);
2074 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002075 case KMEMLEAK_NOT_LEAK:
2076 kmemleak_not_leak(log->ptr);
2077 break;
2078 case KMEMLEAK_IGNORE:
2079 kmemleak_ignore(log->ptr);
2080 break;
2081 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00002082 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002083 break;
2084 case KMEMLEAK_NO_SCAN:
2085 kmemleak_no_scan(log->ptr);
2086 break;
Catalin Marinas94f4a162017-07-06 15:40:22 -07002087 case KMEMLEAK_SET_EXCESS_REF:
2088 object_set_excess_ref((unsigned long)log->ptr,
2089 log->excess_ref);
2090 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002091 default:
Catalin Marinas5f790202011-09-28 12:17:03 +01002092 kmemleak_warn("Unknown early log operation: %d\n",
2093 log->op_type);
2094 }
2095
Li Zefan8910ae892014-04-03 14:46:29 -07002096 if (kmemleak_warning) {
Catalin Marinas5f790202011-09-28 12:17:03 +01002097 print_log_trace(log);
Li Zefan8910ae892014-04-03 14:46:29 -07002098 kmemleak_warning = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002099 }
2100 }
2101}
2102
2103/*
2104 * Late initialization function.
2105 */
2106static int __init kmemleak_late_init(void)
2107{
Li Zefan8910ae892014-04-03 14:46:29 -07002108 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002109
Greg Kroah-Hartman282401d2019-01-22 16:21:12 +01002110 debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops);
Vincent Whitchurchb3537562018-09-04 15:45:44 -07002111
Li Zefan8910ae892014-04-03 14:46:29 -07002112 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002113 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002114 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002115 * small chance that kmemleak_disable() was called immediately
2116 * after setting kmemleak_initialized and we may end up with
2117 * two clean-up threads but serialized by scan_mutex.
2118 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002119 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002120 return -ENOMEM;
2121 }
2122
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -08002123 if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) {
2124 mutex_lock(&scan_mutex);
2125 start_scan_thread();
2126 mutex_unlock(&scan_mutex);
2127 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002128
2129 pr_info("Kernel memory leak detector initialized\n");
2130
2131 return 0;
2132}
2133late_initcall(kmemleak_late_init);