Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com> |
| 4 | * |
| 5 | */ |
Ingo Molnar | 68db0cf | 2017-02-08 18:51:37 +0100 | [diff] [blame] | 6 | #include <linux/sched/task_stack.h> |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 7 | #include <linux/stacktrace.h> |
Steven Rostedt (VMware) | 17911ff | 2019-10-11 17:22:50 -0400 | [diff] [blame] | 8 | #include <linux/security.h> |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 9 | #include <linux/kallsyms.h> |
| 10 | #include <linux/seq_file.h> |
| 11 | #include <linux/spinlock.h> |
| 12 | #include <linux/uaccess.h> |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 13 | #include <linux/ftrace.h> |
| 14 | #include <linux/module.h> |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 15 | #include <linux/sysctl.h> |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 16 | #include <linux/init.h> |
Steven Rostedt | 762e120 | 2011-12-19 22:01:00 -0500 | [diff] [blame] | 17 | |
| 18 | #include <asm/setup.h> |
| 19 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 20 | #include "trace.h" |
| 21 | |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 22 | #define STACK_TRACE_ENTRIES 500 |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 23 | |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 24 | static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES]; |
| 25 | static unsigned stack_trace_index[STACK_TRACE_ENTRIES]; |
| 26 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 27 | static unsigned int stack_trace_nr_entries; |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 28 | static unsigned long stack_trace_max_size; |
| 29 | static arch_spinlock_t stack_trace_max_lock = |
Thomas Gleixner | edc35bd | 2009-12-03 12:38:57 +0100 | [diff] [blame] | 30 | (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 31 | |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 32 | DEFINE_PER_CPU(int, disable_stack_tracer); |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 33 | static DEFINE_MUTEX(stack_sysctl_mutex); |
| 34 | |
| 35 | int stack_tracer_enabled; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 36 | |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 37 | static void print_max_stack(void) |
Minchan Kim | e317218 | 2014-06-02 13:33:12 +0900 | [diff] [blame] | 38 | { |
| 39 | long i; |
| 40 | int size; |
| 41 | |
| 42 | pr_emerg(" Depth Size Location (%d entries)\n" |
| 43 | " ----- ---- --------\n", |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 44 | stack_trace_nr_entries); |
Minchan Kim | e317218 | 2014-06-02 13:33:12 +0900 | [diff] [blame] | 45 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 46 | for (i = 0; i < stack_trace_nr_entries; i++) { |
| 47 | if (i + 1 == stack_trace_nr_entries) |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 48 | size = stack_trace_index[i]; |
Minchan Kim | e317218 | 2014-06-02 13:33:12 +0900 | [diff] [blame] | 49 | else |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 50 | size = stack_trace_index[i] - stack_trace_index[i+1]; |
Minchan Kim | e317218 | 2014-06-02 13:33:12 +0900 | [diff] [blame] | 51 | |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 52 | pr_emerg("%3ld) %8d %5d %pS\n", i, stack_trace_index[i], |
Minchan Kim | e317218 | 2014-06-02 13:33:12 +0900 | [diff] [blame] | 53 | size, (void *)stack_dump_trace[i]); |
| 54 | } |
| 55 | } |
| 56 | |
Steven Rostedt (VMware) | 58fe7a8 | 2019-08-07 12:27:30 -0400 | [diff] [blame] | 57 | /* |
| 58 | * The stack tracer looks for a maximum stack at each call from a function. It |
| 59 | * registers a callback from ftrace, and in that callback it examines the stack |
| 60 | * size. It determines the stack size from the variable passed in, which is the |
| 61 | * address of a local variable in the stack_trace_call() callback function. |
| 62 | * The stack size is calculated by the address of the local variable to the top |
| 63 | * of the current stack. If that size is smaller than the currently saved max |
| 64 | * stack size, nothing more is done. |
| 65 | * |
| 66 | * If the size of the stack is greater than the maximum recorded size, then the |
| 67 | * following algorithm takes place. |
| 68 | * |
| 69 | * For architectures (like x86) that store the function's return address before |
| 70 | * saving the function's local variables, the stack will look something like |
| 71 | * this: |
| 72 | * |
| 73 | * [ top of stack ] |
| 74 | * 0: sys call entry frame |
| 75 | * 10: return addr to entry code |
| 76 | * 11: start of sys_foo frame |
| 77 | * 20: return addr to sys_foo |
| 78 | * 21: start of kernel_func_bar frame |
| 79 | * 30: return addr to kernel_func_bar |
| 80 | * 31: [ do trace stack here ] |
| 81 | * |
| 82 | * The save_stack_trace() is called returning all the functions it finds in the |
| 83 | * current stack. Which would be (from the bottom of the stack to the top): |
| 84 | * |
| 85 | * return addr to kernel_func_bar |
| 86 | * return addr to sys_foo |
| 87 | * return addr to entry code |
| 88 | * |
| 89 | * Now to figure out how much each of these functions' local variable size is, |
| 90 | * a search of the stack is made to find these values. When a match is made, it |
| 91 | * is added to the stack_dump_trace[] array. The offset into the stack is saved |
| 92 | * in the stack_trace_index[] array. The above example would show: |
| 93 | * |
| 94 | * stack_dump_trace[] | stack_trace_index[] |
| 95 | * ------------------ + ------------------- |
| 96 | * return addr to kernel_func_bar | 30 |
| 97 | * return addr to sys_foo | 20 |
| 98 | * return addr to entry | 10 |
| 99 | * |
| 100 | * The print_max_stack() function above, uses these values to print the size of |
| 101 | * each function's portion of the stack. |
| 102 | * |
| 103 | * for (i = 0; i < nr_entries; i++) { |
| 104 | * size = i == nr_entries - 1 ? stack_trace_index[i] : |
| 105 | * stack_trace_index[i] - stack_trace_index[i+1] |
| 106 | * print "%d %d %d %s\n", i, stack_trace_index[i], size, stack_dump_trace[i]); |
| 107 | * } |
| 108 | * |
| 109 | * The above shows |
| 110 | * |
| 111 | * depth size location |
| 112 | * ----- ---- -------- |
| 113 | * 0 30 10 kernel_func_bar |
| 114 | * 1 20 10 sys_foo |
| 115 | * 2 10 10 entry code |
| 116 | * |
| 117 | * Now for architectures that might save the return address after the functions |
| 118 | * local variables (saving the link register before calling nested functions), |
| 119 | * this will cause the stack to look a little different: |
| 120 | * |
| 121 | * [ top of stack ] |
| 122 | * 0: sys call entry frame |
| 123 | * 10: start of sys_foo_frame |
| 124 | * 19: return addr to entry code << lr saved before calling kernel_func_bar |
| 125 | * 20: start of kernel_func_bar frame |
| 126 | * 29: return addr to sys_foo_frame << lr saved before calling next function |
| 127 | * 30: [ do trace stack here ] |
| 128 | * |
| 129 | * Although the functions returned by save_stack_trace() may be the same, the |
| 130 | * placement in the stack will be different. Using the same algorithm as above |
| 131 | * would yield: |
| 132 | * |
| 133 | * stack_dump_trace[] | stack_trace_index[] |
| 134 | * ------------------ + ------------------- |
| 135 | * return addr to kernel_func_bar | 30 |
| 136 | * return addr to sys_foo | 29 |
| 137 | * return addr to entry | 19 |
| 138 | * |
| 139 | * Where the mapping is off by one: |
| 140 | * |
| 141 | * kernel_func_bar stack frame size is 29 - 19 not 30 - 29! |
| 142 | * |
| 143 | * To fix this, if the architecture sets ARCH_RET_ADDR_AFTER_LOCAL_VARS the |
| 144 | * values in stack_trace_index[] are shifted by one to and the number of |
| 145 | * stack trace entries is decremented by one. |
| 146 | * |
| 147 | * stack_dump_trace[] | stack_trace_index[] |
| 148 | * ------------------ + ------------------- |
| 149 | * return addr to kernel_func_bar | 29 |
| 150 | * return addr to sys_foo | 19 |
| 151 | * |
| 152 | * Although the entry function is not displayed, the first function (sys_foo) |
| 153 | * will still include the stack size of it. |
| 154 | */ |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 155 | static void check_stack(unsigned long ip, unsigned long *stack) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 156 | { |
Minchan Kim | e317218 | 2014-06-02 13:33:12 +0900 | [diff] [blame] | 157 | unsigned long this_size, flags; unsigned long *p, *top, *start; |
Steven Rostedt (Red Hat) | 4df2971 | 2013-03-13 23:34:22 -0400 | [diff] [blame] | 158 | static int tracer_frame; |
Mark Rutland | 6aa7de0 | 2017-10-23 14:07:29 -0700 | [diff] [blame] | 159 | int frame_size = READ_ONCE(tracer_frame); |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 160 | int i, x; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 161 | |
Steven Rostedt (Red Hat) | 87889501 | 2013-03-13 20:43:57 -0400 | [diff] [blame] | 162 | this_size = ((unsigned long)stack) & (THREAD_SIZE-1); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 163 | this_size = THREAD_SIZE - this_size; |
Steven Rostedt (Red Hat) | 4df2971 | 2013-03-13 23:34:22 -0400 | [diff] [blame] | 164 | /* Remove the frame of the tracer */ |
| 165 | this_size -= frame_size; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 166 | |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 167 | if (this_size <= stack_trace_max_size) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 168 | return; |
| 169 | |
Steven Rostedt | 81520a1 | 2008-10-06 21:24:18 -0400 | [diff] [blame] | 170 | /* we do not handle interrupt stacks yet */ |
Steven Rostedt (Red Hat) | 87889501 | 2013-03-13 20:43:57 -0400 | [diff] [blame] | 171 | if (!object_is_on_stack(stack)) |
Steven Rostedt | 81520a1 | 2008-10-06 21:24:18 -0400 | [diff] [blame] | 172 | return; |
| 173 | |
Steven Rostedt (Red Hat) | 1904be1 | 2015-10-20 21:48:02 -0400 | [diff] [blame] | 174 | /* Can't do this from NMI context (can cause deadlocks) */ |
| 175 | if (in_nmi()) |
| 176 | return; |
| 177 | |
Steven Rostedt | a5e2588 | 2008-12-02 15:34:05 -0500 | [diff] [blame] | 178 | local_irq_save(flags); |
Steven Rostedt (Red Hat) | d332736 | 2015-11-03 14:50:15 -0500 | [diff] [blame] | 179 | arch_spin_lock(&stack_trace_max_lock); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 180 | |
Steven Rostedt (Red Hat) | 4df2971 | 2013-03-13 23:34:22 -0400 | [diff] [blame] | 181 | /* In case another CPU set the tracer_frame on us */ |
| 182 | if (unlikely(!frame_size)) |
| 183 | this_size -= tracer_frame; |
| 184 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 185 | /* a race could have already updated it */ |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 186 | if (this_size <= stack_trace_max_size) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 187 | goto out; |
| 188 | |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 189 | stack_trace_max_size = this_size; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 190 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 191 | stack_trace_nr_entries = stack_trace_save(stack_dump_trace, |
| 192 | ARRAY_SIZE(stack_dump_trace) - 1, |
| 193 | 0); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 194 | |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 195 | /* Skip over the overhead of the stack tracer itself */ |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 196 | for (i = 0; i < stack_trace_nr_entries; i++) { |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 197 | if (stack_dump_trace[i] == ip) |
| 198 | break; |
| 199 | } |
Steven Rostedt (Red Hat) | d4ecbfc | 2013-03-13 21:25:35 -0400 | [diff] [blame] | 200 | |
| 201 | /* |
Steven Rostedt | 6ccd837 | 2016-01-29 10:22:41 -0500 | [diff] [blame] | 202 | * Some archs may not have the passed in ip in the dump. |
| 203 | * If that happens, we need to show everything. |
| 204 | */ |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 205 | if (i == stack_trace_nr_entries) |
Steven Rostedt | 6ccd837 | 2016-01-29 10:22:41 -0500 | [diff] [blame] | 206 | i = 0; |
| 207 | |
| 208 | /* |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 209 | * Now find where in the stack these are. |
| 210 | */ |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 211 | x = 0; |
Steven Rostedt (Red Hat) | 87889501 | 2013-03-13 20:43:57 -0400 | [diff] [blame] | 212 | start = stack; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 213 | top = (unsigned long *) |
| 214 | (((unsigned long)start & ~(THREAD_SIZE-1)) + THREAD_SIZE); |
| 215 | |
| 216 | /* |
| 217 | * Loop through all the entries. One of the entries may |
| 218 | * for some reason be missed on the stack, so we may |
| 219 | * have to account for them. If they are all there, this |
| 220 | * loop will only happen once. This code only takes place |
| 221 | * on a new max, so it is far from a fast path. |
| 222 | */ |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 223 | while (i < stack_trace_nr_entries) { |
Steven Rostedt | 0a37119 | 2008-12-03 11:04:50 -0500 | [diff] [blame] | 224 | int found = 0; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 225 | |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 226 | stack_trace_index[x] = this_size; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 227 | p = start; |
| 228 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 229 | for (; p < top && i < stack_trace_nr_entries; p++) { |
Yang Shi | 6e22c83 | 2016-02-12 12:46:00 -0800 | [diff] [blame] | 230 | /* |
| 231 | * The READ_ONCE_NOCHECK is used to let KASAN know that |
| 232 | * this is not a stack-out-of-bounds error. |
| 233 | */ |
| 234 | if ((READ_ONCE_NOCHECK(*p)) == stack_dump_trace[i]) { |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 235 | stack_dump_trace[x] = stack_dump_trace[i++]; |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 236 | this_size = stack_trace_index[x++] = |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 237 | (top - p) * sizeof(unsigned long); |
Steven Rostedt | 0a37119 | 2008-12-03 11:04:50 -0500 | [diff] [blame] | 238 | found = 1; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 239 | /* Start the search from here */ |
| 240 | start = p + 1; |
Steven Rostedt (Red Hat) | 4df2971 | 2013-03-13 23:34:22 -0400 | [diff] [blame] | 241 | /* |
| 242 | * We do not want to show the overhead |
| 243 | * of the stack tracer stack in the |
| 244 | * max stack. If we haven't figured |
| 245 | * out what that is, then figure it out |
| 246 | * now. |
| 247 | */ |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 248 | if (unlikely(!tracer_frame)) { |
Steven Rostedt (Red Hat) | 4df2971 | 2013-03-13 23:34:22 -0400 | [diff] [blame] | 249 | tracer_frame = (p - stack) * |
| 250 | sizeof(unsigned long); |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 251 | stack_trace_max_size -= tracer_frame; |
Steven Rostedt (Red Hat) | 4df2971 | 2013-03-13 23:34:22 -0400 | [diff] [blame] | 252 | } |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 253 | } |
| 254 | } |
| 255 | |
Steven Rostedt | 0a37119 | 2008-12-03 11:04:50 -0500 | [diff] [blame] | 256 | if (!found) |
| 257 | i++; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 258 | } |
| 259 | |
Steven Rostedt (VMware) | f7edb45 | 2019-08-07 11:28:59 -0400 | [diff] [blame] | 260 | #ifdef ARCH_FTRACE_SHIFT_STACK_TRACER |
| 261 | /* |
| 262 | * Some archs will store the link register before calling |
| 263 | * nested functions. This means the saved return address |
| 264 | * comes after the local storage, and we need to shift |
| 265 | * for that. |
| 266 | */ |
| 267 | if (x > 1) { |
| 268 | memmove(&stack_trace_index[0], &stack_trace_index[1], |
| 269 | sizeof(stack_trace_index[0]) * (x - 1)); |
| 270 | x--; |
| 271 | } |
| 272 | #endif |
| 273 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 274 | stack_trace_nr_entries = x; |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 275 | |
Aaron Tomlin | a70857e | 2014-09-12 14:16:18 +0100 | [diff] [blame] | 276 | if (task_stack_end_corrupted(current)) { |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 277 | print_max_stack(); |
Minchan Kim | e317218 | 2014-06-02 13:33:12 +0900 | [diff] [blame] | 278 | BUG(); |
| 279 | } |
| 280 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 281 | out: |
Steven Rostedt (Red Hat) | d332736 | 2015-11-03 14:50:15 -0500 | [diff] [blame] | 282 | arch_spin_unlock(&stack_trace_max_lock); |
Steven Rostedt | a5e2588 | 2008-12-02 15:34:05 -0500 | [diff] [blame] | 283 | local_irq_restore(flags); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 284 | } |
| 285 | |
Steven Rostedt (VMware) | b8299d3 | 2020-01-02 22:02:41 -0500 | [diff] [blame] | 286 | /* Some archs may not define MCOUNT_INSN_SIZE */ |
| 287 | #ifndef MCOUNT_INSN_SIZE |
| 288 | # define MCOUNT_INSN_SIZE 0 |
| 289 | #endif |
| 290 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 291 | static void |
Steven Rostedt | a1e2e31 | 2011-08-09 12:50:46 -0400 | [diff] [blame] | 292 | stack_trace_call(unsigned long ip, unsigned long parent_ip, |
Steven Rostedt (VMware) | d19ad07 | 2020-10-28 17:42:17 -0400 | [diff] [blame] | 293 | struct ftrace_ops *op, struct ftrace_regs *fregs) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 294 | { |
Steven Rostedt (Red Hat) | 87889501 | 2013-03-13 20:43:57 -0400 | [diff] [blame] | 295 | unsigned long stack; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 296 | |
Steven Rostedt | 5168ae5 | 2010-06-03 09:36:50 -0400 | [diff] [blame] | 297 | preempt_disable_notrace(); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 298 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 299 | /* no atomic needed, we only modify this variable by this cpu */ |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 300 | __this_cpu_inc(disable_stack_tracer); |
| 301 | if (__this_cpu_read(disable_stack_tracer) != 1) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 302 | goto out; |
| 303 | |
Steven Rostedt (VMware) | b00d607 | 2017-12-05 04:41:51 -0500 | [diff] [blame] | 304 | /* If rcu is not watching, then save stack trace can fail */ |
| 305 | if (!rcu_is_watching()) |
| 306 | goto out; |
| 307 | |
Steven Rostedt (Red Hat) | 72ac426 | 2015-07-16 13:24:54 -0400 | [diff] [blame] | 308 | ip += MCOUNT_INSN_SIZE; |
Steven Rostedt (Red Hat) | 4df2971 | 2013-03-13 23:34:22 -0400 | [diff] [blame] | 309 | |
| 310 | check_stack(ip, &stack); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 311 | |
| 312 | out: |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 313 | __this_cpu_dec(disable_stack_tracer); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 314 | /* prevent recursion in schedule */ |
Steven Rostedt | 5168ae5 | 2010-06-03 09:36:50 -0400 | [diff] [blame] | 315 | preempt_enable_notrace(); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 316 | } |
| 317 | |
| 318 | static struct ftrace_ops trace_ops __read_mostly = |
| 319 | { |
| 320 | .func = stack_trace_call, |
| 321 | }; |
| 322 | |
| 323 | static ssize_t |
| 324 | stack_max_size_read(struct file *filp, char __user *ubuf, |
| 325 | size_t count, loff_t *ppos) |
| 326 | { |
| 327 | unsigned long *ptr = filp->private_data; |
| 328 | char buf[64]; |
| 329 | int r; |
| 330 | |
| 331 | r = snprintf(buf, sizeof(buf), "%ld\n", *ptr); |
| 332 | if (r > sizeof(buf)) |
| 333 | r = sizeof(buf); |
| 334 | return simple_read_from_buffer(ubuf, count, ppos, buf, r); |
| 335 | } |
| 336 | |
| 337 | static ssize_t |
| 338 | stack_max_size_write(struct file *filp, const char __user *ubuf, |
| 339 | size_t count, loff_t *ppos) |
| 340 | { |
| 341 | long *ptr = filp->private_data; |
| 342 | unsigned long val, flags; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 343 | int ret; |
| 344 | |
Peter Huewe | 22fe9b5 | 2011-06-07 21:58:27 +0200 | [diff] [blame] | 345 | ret = kstrtoul_from_user(ubuf, count, 10, &val); |
| 346 | if (ret) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 347 | return ret; |
| 348 | |
Steven Rostedt | a5e2588 | 2008-12-02 15:34:05 -0500 | [diff] [blame] | 349 | local_irq_save(flags); |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 350 | |
| 351 | /* |
| 352 | * In case we trace inside arch_spin_lock() or after (NMI), |
| 353 | * we will cause circular lock, so we also need to increase |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 354 | * the percpu disable_stack_tracer here. |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 355 | */ |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 356 | __this_cpu_inc(disable_stack_tracer); |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 357 | |
Steven Rostedt (Red Hat) | d332736 | 2015-11-03 14:50:15 -0500 | [diff] [blame] | 358 | arch_spin_lock(&stack_trace_max_lock); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 359 | *ptr = val; |
Steven Rostedt (Red Hat) | d332736 | 2015-11-03 14:50:15 -0500 | [diff] [blame] | 360 | arch_spin_unlock(&stack_trace_max_lock); |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 361 | |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 362 | __this_cpu_dec(disable_stack_tracer); |
Steven Rostedt | a5e2588 | 2008-12-02 15:34:05 -0500 | [diff] [blame] | 363 | local_irq_restore(flags); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 364 | |
| 365 | return count; |
| 366 | } |
| 367 | |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 368 | static const struct file_operations stack_max_size_fops = { |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 369 | .open = tracing_open_generic, |
| 370 | .read = stack_max_size_read, |
| 371 | .write = stack_max_size_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 372 | .llseek = default_llseek, |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 373 | }; |
| 374 | |
| 375 | static void * |
Li Zefan | 2fc5f0c | 2009-08-17 16:53:37 +0800 | [diff] [blame] | 376 | __next(struct seq_file *m, loff_t *pos) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 377 | { |
Li Zefan | 2fc5f0c | 2009-08-17 16:53:37 +0800 | [diff] [blame] | 378 | long n = *pos - 1; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 379 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 380 | if (n >= stack_trace_nr_entries) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 381 | return NULL; |
| 382 | |
Li Zefan | 2fc5f0c | 2009-08-17 16:53:37 +0800 | [diff] [blame] | 383 | m->private = (void *)n; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 384 | return &m->private; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 385 | } |
| 386 | |
Li Zefan | 2fc5f0c | 2009-08-17 16:53:37 +0800 | [diff] [blame] | 387 | static void * |
| 388 | t_next(struct seq_file *m, void *v, loff_t *pos) |
| 389 | { |
| 390 | (*pos)++; |
| 391 | return __next(m, pos); |
| 392 | } |
| 393 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 394 | static void *t_start(struct seq_file *m, loff_t *pos) |
| 395 | { |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 396 | local_irq_disable(); |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 397 | |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 398 | __this_cpu_inc(disable_stack_tracer); |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 399 | |
Steven Rostedt (Red Hat) | d332736 | 2015-11-03 14:50:15 -0500 | [diff] [blame] | 400 | arch_spin_lock(&stack_trace_max_lock); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 401 | |
Liming Wang | 522a110 | 2008-11-21 11:00:18 +0800 | [diff] [blame] | 402 | if (*pos == 0) |
| 403 | return SEQ_START_TOKEN; |
| 404 | |
Li Zefan | 2fc5f0c | 2009-08-17 16:53:37 +0800 | [diff] [blame] | 405 | return __next(m, pos); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 406 | } |
| 407 | |
| 408 | static void t_stop(struct seq_file *m, void *p) |
| 409 | { |
Steven Rostedt (Red Hat) | d332736 | 2015-11-03 14:50:15 -0500 | [diff] [blame] | 410 | arch_spin_unlock(&stack_trace_max_lock); |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 411 | |
Steven Rostedt (VMware) | 8aaf1ee | 2017-04-06 15:47:32 -0400 | [diff] [blame] | 412 | __this_cpu_dec(disable_stack_tracer); |
Lai Jiangshan | 4f48f8b | 2010-02-02 15:32:09 +0800 | [diff] [blame] | 413 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 414 | local_irq_enable(); |
| 415 | } |
| 416 | |
Joe Perches | 962e370 | 2015-04-15 16:18:22 -0700 | [diff] [blame] | 417 | static void trace_lookup_stack(struct seq_file *m, long i) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 418 | { |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 419 | unsigned long addr = stack_dump_trace[i]; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 420 | |
Joe Perches | 962e370 | 2015-04-15 16:18:22 -0700 | [diff] [blame] | 421 | seq_printf(m, "%pS\n", (void *)addr); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 422 | } |
| 423 | |
Steven Rostedt | e447e1df | 2009-03-12 19:42:29 -0400 | [diff] [blame] | 424 | static void print_disabled(struct seq_file *m) |
| 425 | { |
| 426 | seq_puts(m, "#\n" |
| 427 | "# Stack tracer disabled\n" |
| 428 | "#\n" |
| 429 | "# To enable the stack tracer, either add 'stacktrace' to the\n" |
| 430 | "# kernel command line\n" |
| 431 | "# or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'\n" |
| 432 | "#\n"); |
| 433 | } |
| 434 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 435 | static int t_show(struct seq_file *m, void *v) |
| 436 | { |
Liming Wang | 522a110 | 2008-11-21 11:00:18 +0800 | [diff] [blame] | 437 | long i; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 438 | int size; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 439 | |
Liming Wang | 522a110 | 2008-11-21 11:00:18 +0800 | [diff] [blame] | 440 | if (v == SEQ_START_TOKEN) { |
Steven Rostedt | eb1871f | 2009-03-13 00:00:58 -0400 | [diff] [blame] | 441 | seq_printf(m, " Depth Size Location" |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 442 | " (%d entries)\n" |
Steven Rostedt | eb1871f | 2009-03-13 00:00:58 -0400 | [diff] [blame] | 443 | " ----- ---- --------\n", |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 444 | stack_trace_nr_entries); |
Steven Rostedt | e447e1df | 2009-03-12 19:42:29 -0400 | [diff] [blame] | 445 | |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 446 | if (!stack_tracer_enabled && !stack_trace_max_size) |
Steven Rostedt | e447e1df | 2009-03-12 19:42:29 -0400 | [diff] [blame] | 447 | print_disabled(m); |
| 448 | |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 449 | return 0; |
| 450 | } |
| 451 | |
Liming Wang | 522a110 | 2008-11-21 11:00:18 +0800 | [diff] [blame] | 452 | i = *(long *)v; |
| 453 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 454 | if (i >= stack_trace_nr_entries) |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 455 | return 0; |
| 456 | |
Thomas Gleixner | 9f50c91 | 2019-04-25 11:45:17 +0200 | [diff] [blame] | 457 | if (i + 1 == stack_trace_nr_entries) |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 458 | size = stack_trace_index[i]; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 459 | else |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 460 | size = stack_trace_index[i] - stack_trace_index[i+1]; |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 461 | |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 462 | seq_printf(m, "%3ld) %8d %5d ", i, stack_trace_index[i], size); |
Steven Rostedt | 1b6cced | 2008-08-29 16:51:43 -0400 | [diff] [blame] | 463 | |
| 464 | trace_lookup_stack(m, i); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 465 | |
| 466 | return 0; |
| 467 | } |
| 468 | |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 469 | static const struct seq_operations stack_trace_seq_ops = { |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 470 | .start = t_start, |
| 471 | .next = t_next, |
| 472 | .stop = t_stop, |
| 473 | .show = t_show, |
| 474 | }; |
| 475 | |
| 476 | static int stack_trace_open(struct inode *inode, struct file *file) |
| 477 | { |
Steven Rostedt (VMware) | 17911ff | 2019-10-11 17:22:50 -0400 | [diff] [blame] | 478 | int ret; |
| 479 | |
| 480 | ret = security_locked_down(LOCKDOWN_TRACEFS); |
| 481 | if (ret) |
| 482 | return ret; |
| 483 | |
Li Zefan | d8cc1ab | 2009-07-23 11:28:40 +0800 | [diff] [blame] | 484 | return seq_open(file, &stack_trace_seq_ops); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 485 | } |
| 486 | |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 487 | static const struct file_operations stack_trace_fops = { |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 488 | .open = stack_trace_open, |
| 489 | .read = seq_read, |
| 490 | .llseek = seq_lseek, |
Li Zefan | d8cc1ab | 2009-07-23 11:28:40 +0800 | [diff] [blame] | 491 | .release = seq_release, |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 492 | }; |
| 493 | |
Steven Rostedt (VMware) | bbd1d27 | 2017-07-11 19:21:04 -0400 | [diff] [blame] | 494 | #ifdef CONFIG_DYNAMIC_FTRACE |
| 495 | |
Steven Rostedt | d2d45c7 | 2011-12-19 14:44:09 -0500 | [diff] [blame] | 496 | static int |
| 497 | stack_trace_filter_open(struct inode *inode, struct file *file) |
| 498 | { |
Steven Rostedt (VMware) | 0f17976 | 2017-06-29 10:05:45 -0400 | [diff] [blame] | 499 | struct ftrace_ops *ops = inode->i_private; |
| 500 | |
Steven Rostedt (VMware) | 17911ff | 2019-10-11 17:22:50 -0400 | [diff] [blame] | 501 | /* Checks for tracefs lockdown */ |
Steven Rostedt (VMware) | 0f17976 | 2017-06-29 10:05:45 -0400 | [diff] [blame] | 502 | return ftrace_regex_open(ops, FTRACE_ITER_FILTER, |
Steven Rostedt | d2d45c7 | 2011-12-19 14:44:09 -0500 | [diff] [blame] | 503 | inode, file); |
| 504 | } |
| 505 | |
| 506 | static const struct file_operations stack_trace_filter_fops = { |
| 507 | .open = stack_trace_filter_open, |
| 508 | .read = seq_read, |
| 509 | .write = ftrace_filter_write, |
Steven Rostedt (Red Hat) | 098c879e | 2013-12-21 17:39:40 -0500 | [diff] [blame] | 510 | .llseek = tracing_lseek, |
Steven Rostedt | d2d45c7 | 2011-12-19 14:44:09 -0500 | [diff] [blame] | 511 | .release = ftrace_regex_release, |
| 512 | }; |
| 513 | |
Steven Rostedt (VMware) | bbd1d27 | 2017-07-11 19:21:04 -0400 | [diff] [blame] | 514 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
| 515 | |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 516 | int |
Christoph Hellwig | 7ff0d44 | 2020-06-03 07:52:37 +0200 | [diff] [blame] | 517 | stack_trace_sysctl(struct ctl_table *table, int write, void *buffer, |
| 518 | size_t *lenp, loff_t *ppos) |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 519 | { |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 520 | int was_enabled; |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 521 | int ret; |
| 522 | |
| 523 | mutex_lock(&stack_sysctl_mutex); |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 524 | was_enabled = !!stack_tracer_enabled; |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 525 | |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 526 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 527 | |
Thomas Gleixner | 3d9a807 | 2019-04-25 11:44:54 +0200 | [diff] [blame] | 528 | if (ret || !write || (was_enabled == !!stack_tracer_enabled)) |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 529 | goto out; |
| 530 | |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 531 | if (stack_tracer_enabled) |
| 532 | register_ftrace_function(&trace_ops); |
| 533 | else |
| 534 | unregister_ftrace_function(&trace_ops); |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 535 | out: |
| 536 | mutex_unlock(&stack_sysctl_mutex); |
| 537 | return ret; |
| 538 | } |
| 539 | |
Steven Rostedt | 762e120 | 2011-12-19 22:01:00 -0500 | [diff] [blame] | 540 | static char stack_trace_filter_buf[COMMAND_LINE_SIZE+1] __initdata; |
| 541 | |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 542 | static __init int enable_stacktrace(char *str) |
| 543 | { |
Steven Rostedt (VMware) | 3d739c1 | 2018-12-21 23:10:26 -0500 | [diff] [blame] | 544 | int len; |
| 545 | |
| 546 | if ((len = str_has_prefix(str, "_filter="))) |
| 547 | strncpy(stack_trace_filter_buf, str + len, COMMAND_LINE_SIZE); |
Steven Rostedt | 762e120 | 2011-12-19 22:01:00 -0500 | [diff] [blame] | 548 | |
Steven Rostedt | e05a43b | 2008-12-17 09:43:00 -0500 | [diff] [blame] | 549 | stack_tracer_enabled = 1; |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 550 | return 1; |
| 551 | } |
| 552 | __setup("stacktrace", enable_stacktrace); |
| 553 | |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 554 | static __init int stack_trace_init(void) |
| 555 | { |
Wei Yang | 22c36b1 | 2020-07-12 09:10:36 +0800 | [diff] [blame] | 556 | int ret; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 557 | |
Wei Yang | 22c36b1 | 2020-07-12 09:10:36 +0800 | [diff] [blame] | 558 | ret = tracing_init_dentry(); |
| 559 | if (ret) |
Namhyung Kim | ed6f1c9 | 2013-04-10 09:18:12 +0900 | [diff] [blame] | 560 | return 0; |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 561 | |
Steven Rostedt (VMware) | 21ccc9c | 2021-08-18 11:24:51 -0400 | [diff] [blame] | 562 | trace_create_file("stack_max_size", TRACE_MODE_WRITE, NULL, |
AKASHI Takahiro | bb99d8c | 2015-10-30 14:25:39 +0900 | [diff] [blame] | 563 | &stack_trace_max_size, &stack_max_size_fops); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 564 | |
Steven Rostedt (VMware) | 21ccc9c | 2021-08-18 11:24:51 -0400 | [diff] [blame] | 565 | trace_create_file("stack_trace", TRACE_MODE_READ, NULL, |
Frederic Weisbecker | 5452af6 | 2009-03-27 00:25:38 +0100 | [diff] [blame] | 566 | NULL, &stack_trace_fops); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 567 | |
Steven Rostedt (VMware) | bbd1d27 | 2017-07-11 19:21:04 -0400 | [diff] [blame] | 568 | #ifdef CONFIG_DYNAMIC_FTRACE |
Steven Rostedt (VMware) | 21ccc9c | 2021-08-18 11:24:51 -0400 | [diff] [blame] | 569 | trace_create_file("stack_trace_filter", TRACE_MODE_WRITE, NULL, |
Steven Rostedt (VMware) | 0f17976 | 2017-06-29 10:05:45 -0400 | [diff] [blame] | 570 | &trace_ops, &stack_trace_filter_fops); |
Steven Rostedt (VMware) | bbd1d27 | 2017-07-11 19:21:04 -0400 | [diff] [blame] | 571 | #endif |
Steven Rostedt | d2d45c7 | 2011-12-19 14:44:09 -0500 | [diff] [blame] | 572 | |
Steven Rostedt | 762e120 | 2011-12-19 22:01:00 -0500 | [diff] [blame] | 573 | if (stack_trace_filter_buf[0]) |
| 574 | ftrace_set_early_filter(&trace_ops, stack_trace_filter_buf, 1); |
| 575 | |
Steven Rostedt | e05a43b | 2008-12-17 09:43:00 -0500 | [diff] [blame] | 576 | if (stack_tracer_enabled) |
Steven Rostedt | f38f1d2 | 2008-12-16 23:06:40 -0500 | [diff] [blame] | 577 | register_ftrace_function(&trace_ops); |
Steven Rostedt | e5a81b6 | 2008-08-27 23:31:01 -0400 | [diff] [blame] | 578 | |
| 579 | return 0; |
| 580 | } |
| 581 | |
| 582 | device_initcall(stack_trace_init); |