Commit | Line | Data |
---|---|---|
867e359b CM |
1 | /* |
2 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation, version 2. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
11 | * NON INFRINGEMENT. See the GNU General Public License for | |
12 | * more details. | |
13 | */ | |
14 | ||
15 | #include <linux/sched.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/kprobes.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/pfn.h> | |
20 | #include <linux/kallsyms.h> | |
21 | #include <linux/stacktrace.h> | |
22 | #include <linux/uaccess.h> | |
23 | #include <linux/mmzone.h> | |
5f639fdc CM |
24 | #include <linux/dcache.h> |
25 | #include <linux/fs.h> | |
47ad7b9b | 26 | #include <linux/hardirq.h> |
0cc96a74 | 27 | #include <linux/string.h> |
867e359b CM |
28 | #include <asm/backtrace.h> |
29 | #include <asm/page.h> | |
867e359b | 30 | #include <asm/ucontext.h> |
34f2c0ac | 31 | #include <asm/switch_to.h> |
867e359b CM |
32 | #include <asm/sigframe.h> |
33 | #include <asm/stack.h> | |
4a556f4f | 34 | #include <asm/vdso.h> |
867e359b CM |
35 | #include <arch/abi.h> |
36 | #include <arch/interrupts.h> | |
37 | ||
dabe98c9 CM |
38 | #define KBT_ONGOING 0 /* Backtrace still ongoing */ |
39 | #define KBT_DONE 1 /* Backtrace cleanly completed */ | |
40 | #define KBT_RUNNING 2 /* Can't run backtrace on a running task */ | |
41 | #define KBT_LOOP 3 /* Backtrace entered a loop */ | |
867e359b CM |
42 | |
43 | /* Is address on the specified kernel stack? */ | |
93013a0f | 44 | static int in_kernel_stack(struct KBacktraceIterator *kbt, unsigned long sp) |
867e359b CM |
45 | { |
46 | ulong kstack_base = (ulong) kbt->task->stack; | |
47 | if (kstack_base == 0) /* corrupt task pointer; just follow stack... */ | |
48 | return sp >= PAGE_OFFSET && sp < (unsigned long)high_memory; | |
49 | return sp >= kstack_base && sp < kstack_base + THREAD_SIZE; | |
50 | } | |
51 | ||
867e359b | 52 | /* Callback for backtracer; basically a glorified memcpy */ |
93013a0f | 53 | static bool read_memory_func(void *result, unsigned long address, |
867e359b CM |
54 | unsigned int size, void *vkbt) |
55 | { | |
56 | int retval; | |
57 | struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt; | |
5f639fdc CM |
58 | |
59 | if (address == 0) | |
60 | return 0; | |
3cebbafd | 61 | if (__kernel_text_address(address)) { |
867e359b CM |
62 | /* OK to read kernel code. */ |
63 | } else if (address >= PAGE_OFFSET) { | |
64 | /* We only tolerate kernel-space reads of this task's stack */ | |
65 | if (!in_kernel_stack(kbt, address)) | |
66 | return 0; | |
5f639fdc CM |
67 | } else if (!kbt->is_current) { |
68 | return 0; /* can't read from other user address spaces */ | |
867e359b CM |
69 | } |
70 | pagefault_disable(); | |
0707ad30 CM |
71 | retval = __copy_from_user_inatomic(result, |
72 | (void __user __force *)address, | |
867e359b CM |
73 | size); |
74 | pagefault_enable(); | |
75 | return (retval == 0); | |
76 | } | |
77 | ||
78 | /* Return a pt_regs pointer for a valid fault handler frame */ | |
79 | static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt) | |
80 | { | |
5ac65abd | 81 | char fault[64]; |
93013a0f | 82 | unsigned long sp = kbt->it.sp; |
867e359b CM |
83 | struct pt_regs *p; |
84 | ||
5f639fdc CM |
85 | if (sp % sizeof(long) != 0) |
86 | return NULL; | |
867e359b CM |
87 | if (!in_kernel_stack(kbt, sp)) |
88 | return NULL; | |
89 | if (!in_kernel_stack(kbt, sp + C_ABI_SAVE_AREA_SIZE + PTREGS_SIZE-1)) | |
90 | return NULL; | |
91 | p = (struct pt_regs *)(sp + C_ABI_SAVE_AREA_SIZE); | |
5ac65abd CM |
92 | if (kbt->verbose) { /* else we aren't going to use it */ |
93 | if (p->faultnum == INT_SWINT_1 || | |
94 | p->faultnum == INT_SWINT_1_SIGRETURN) | |
95 | snprintf(fault, sizeof(fault), | |
96 | "syscall %ld", p->regs[TREG_SYSCALL_NR]); | |
97 | else | |
98 | snprintf(fault, sizeof(fault), | |
867e359b | 99 | "interrupt %ld", p->faultnum); |
867e359b CM |
100 | } |
101 | if (EX1_PL(p->ex1) == KERNEL_PL && | |
3cebbafd | 102 | __kernel_text_address(p->pc) && |
867e359b CM |
103 | in_kernel_stack(kbt, p->sp) && |
104 | p->sp >= sp) { | |
105 | if (kbt->verbose) | |
0707ad30 | 106 | pr_err(" <%s while in kernel mode>\n", fault); |
051168df | 107 | } else if (user_mode(p) && |
3ef23111 | 108 | p->sp < PAGE_OFFSET && p->sp != 0) { |
867e359b | 109 | if (kbt->verbose) |
0707ad30 | 110 | pr_err(" <%s while in user mode>\n", fault); |
9088616f | 111 | } else { |
47ad7b9b | 112 | if (kbt->verbose && (p->pc != 0 || p->sp != 0 || p->ex1 != 0)) |
9088616f CIK |
113 | pr_err(" (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n", |
114 | p->pc, p->sp, p->ex1); | |
115 | return NULL; | |
867e359b | 116 | } |
9088616f CIK |
117 | if (kbt->profile && ((1ULL << p->faultnum) & QUEUED_INTERRUPTS) != 0) |
118 | return NULL; | |
119 | return p; | |
867e359b CM |
120 | } |
121 | ||
47ad7b9b CM |
122 | /* Is the iterator pointing to a sigreturn trampoline? */ |
123 | static int is_sigreturn(struct KBacktraceIterator *kbt) | |
867e359b | 124 | { |
47ad7b9b CM |
125 | return kbt->task->mm && |
126 | (kbt->it.pc == ((ulong)kbt->task->mm->context.vdso_base + | |
127 | (ulong)&__vdso_rt_sigreturn)); | |
867e359b CM |
128 | } |
129 | ||
130 | /* Return a pt_regs pointer for a valid signal handler frame */ | |
5f639fdc CM |
131 | static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt, |
132 | struct rt_sigframe* kframe) | |
867e359b CM |
133 | { |
134 | BacktraceIterator *b = &kbt->it; | |
135 | ||
47ad7b9b | 136 | if (is_sigreturn(kbt) && b->sp < PAGE_OFFSET && |
5f639fdc CM |
137 | b->sp % sizeof(long) == 0) { |
138 | int retval; | |
139 | pagefault_disable(); | |
140 | retval = __copy_from_user_inatomic( | |
141 | kframe, (void __user __force *)b->sp, | |
142 | sizeof(*kframe)); | |
143 | pagefault_enable(); | |
144 | if (retval != 0 || | |
145 | (unsigned int)(kframe->info.si_signo) >= _NSIG) | |
867e359b | 146 | return NULL; |
867e359b | 147 | if (kbt->verbose) { |
0707ad30 | 148 | pr_err(" <received signal %d>\n", |
5f639fdc | 149 | kframe->info.si_signo); |
867e359b | 150 | } |
5f639fdc | 151 | return (struct pt_regs *)&kframe->uc.uc_mcontext; |
867e359b CM |
152 | } |
153 | return NULL; | |
154 | } | |
155 | ||
867e359b CM |
156 | static int KBacktraceIterator_restart(struct KBacktraceIterator *kbt) |
157 | { | |
158 | struct pt_regs *p; | |
5f639fdc | 159 | struct rt_sigframe kframe; |
867e359b CM |
160 | |
161 | p = valid_fault_handler(kbt); | |
162 | if (p == NULL) | |
5f639fdc | 163 | p = valid_sigframe(kbt, &kframe); |
867e359b CM |
164 | if (p == NULL) |
165 | return 0; | |
166 | backtrace_init(&kbt->it, read_memory_func, kbt, | |
167 | p->pc, p->lr, p->sp, p->regs[52]); | |
168 | kbt->new_context = 1; | |
169 | return 1; | |
170 | } | |
171 | ||
172 | /* Find a frame that isn't a sigreturn, if there is one. */ | |
173 | static int KBacktraceIterator_next_item_inclusive( | |
174 | struct KBacktraceIterator *kbt) | |
175 | { | |
176 | for (;;) { | |
177 | do { | |
47ad7b9b | 178 | if (!is_sigreturn(kbt)) |
dabe98c9 | 179 | return KBT_ONGOING; |
867e359b CM |
180 | } while (backtrace_next(&kbt->it)); |
181 | ||
182 | if (!KBacktraceIterator_restart(kbt)) | |
dabe98c9 | 183 | return KBT_DONE; |
867e359b CM |
184 | } |
185 | } | |
186 | ||
187 | /* | |
188 | * If the current sp is on a page different than what we recorded | |
189 | * as the top-of-kernel-stack last time we context switched, we have | |
190 | * probably blown the stack, and nothing is going to work out well. | |
191 | * If we can at least get out a warning, that may help the debug, | |
192 | * though we probably won't be able to backtrace into the code that | |
193 | * actually did the recursive damage. | |
194 | */ | |
195 | static void validate_stack(struct pt_regs *regs) | |
196 | { | |
bc1a298f | 197 | int cpu = raw_smp_processor_id(); |
867e359b | 198 | unsigned long ksp0 = get_current_ksp0(); |
35f05976 | 199 | unsigned long ksp0_base = ksp0 & -THREAD_SIZE; |
867e359b CM |
200 | unsigned long sp = stack_pointer; |
201 | ||
202 | if (EX1_PL(regs->ex1) == KERNEL_PL && regs->sp >= ksp0) { | |
35f05976 | 203 | pr_err("WARNING: cpu %d: kernel stack %#lx..%#lx underrun!\n" |
867e359b | 204 | " sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n", |
35f05976 | 205 | cpu, ksp0_base, ksp0, sp, regs->sp, regs->pc, regs->lr); |
867e359b CM |
206 | } |
207 | ||
208 | else if (sp < ksp0_base + sizeof(struct thread_info)) { | |
35f05976 | 209 | pr_err("WARNING: cpu %d: kernel stack %#lx..%#lx overrun!\n" |
867e359b | 210 | " sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n", |
35f05976 | 211 | cpu, ksp0_base, ksp0, sp, regs->sp, regs->pc, regs->lr); |
867e359b CM |
212 | } |
213 | } | |
214 | ||
215 | void KBacktraceIterator_init(struct KBacktraceIterator *kbt, | |
216 | struct task_struct *t, struct pt_regs *regs) | |
217 | { | |
93013a0f | 218 | unsigned long pc, lr, sp, r52; |
867e359b CM |
219 | int is_current; |
220 | ||
221 | /* | |
222 | * Set up callback information. We grab the kernel stack base | |
5f639fdc | 223 | * so we will allow reads of that address range. |
867e359b | 224 | */ |
5f639fdc | 225 | is_current = (t == NULL || t == current); |
867e359b CM |
226 | kbt->is_current = is_current; |
227 | if (is_current) | |
228 | t = validate_current(); | |
229 | kbt->task = t; | |
867e359b CM |
230 | kbt->verbose = 0; /* override in caller if desired */ |
231 | kbt->profile = 0; /* override in caller if desired */ | |
dabe98c9 | 232 | kbt->end = KBT_ONGOING; |
5f639fdc CM |
233 | kbt->new_context = 1; |
234 | if (is_current) | |
867e359b | 235 | validate_stack(regs); |
867e359b CM |
236 | |
237 | if (regs == NULL) { | |
867e359b CM |
238 | if (is_current || t->state == TASK_RUNNING) { |
239 | /* Can't do this; we need registers */ | |
dabe98c9 | 240 | kbt->end = KBT_RUNNING; |
867e359b CM |
241 | return; |
242 | } | |
0707ad30 | 243 | pc = get_switch_to_pc(); |
867e359b CM |
244 | lr = t->thread.pc; |
245 | sp = t->thread.ksp; | |
246 | r52 = 0; | |
247 | } else { | |
248 | pc = regs->pc; | |
249 | lr = regs->lr; | |
250 | sp = regs->sp; | |
251 | r52 = regs->regs[52]; | |
252 | } | |
253 | ||
254 | backtrace_init(&kbt->it, read_memory_func, kbt, pc, lr, sp, r52); | |
dabe98c9 | 255 | kbt->end = KBacktraceIterator_next_item_inclusive(kbt); |
867e359b CM |
256 | } |
257 | EXPORT_SYMBOL(KBacktraceIterator_init); | |
258 | ||
259 | int KBacktraceIterator_end(struct KBacktraceIterator *kbt) | |
260 | { | |
dabe98c9 | 261 | return kbt->end != KBT_ONGOING; |
867e359b CM |
262 | } |
263 | EXPORT_SYMBOL(KBacktraceIterator_end); | |
264 | ||
265 | void KBacktraceIterator_next(struct KBacktraceIterator *kbt) | |
266 | { | |
93013a0f | 267 | unsigned long old_pc = kbt->it.pc, old_sp = kbt->it.sp; |
867e359b | 268 | kbt->new_context = 0; |
dabe98c9 CM |
269 | if (!backtrace_next(&kbt->it) && !KBacktraceIterator_restart(kbt)) { |
270 | kbt->end = KBT_DONE; | |
271 | return; | |
272 | } | |
273 | kbt->end = KBacktraceIterator_next_item_inclusive(kbt); | |
274 | if (old_pc == kbt->it.pc && old_sp == kbt->it.sp) { | |
275 | /* Trapped in a loop; give up. */ | |
276 | kbt->end = KBT_LOOP; | |
277 | } | |
867e359b CM |
278 | } |
279 | EXPORT_SYMBOL(KBacktraceIterator_next); | |
280 | ||
5f639fdc CM |
281 | static void describe_addr(struct KBacktraceIterator *kbt, |
282 | unsigned long address, | |
283 | int have_mmap_sem, char *buf, size_t bufsize) | |
284 | { | |
285 | struct vm_area_struct *vma; | |
286 | size_t namelen, remaining; | |
287 | unsigned long size, offset, adjust; | |
288 | char *p, *modname; | |
289 | const char *name; | |
290 | int rc; | |
291 | ||
292 | /* | |
293 | * Look one byte back for every caller frame (i.e. those that | |
294 | * aren't a new context) so we look up symbol data for the | |
295 | * call itself, not the following instruction, which may be on | |
296 | * a different line (or in a different function). | |
297 | */ | |
298 | adjust = !kbt->new_context; | |
299 | address -= adjust; | |
300 | ||
301 | if (address >= PAGE_OFFSET) { | |
302 | /* Handle kernel symbols. */ | |
303 | BUG_ON(bufsize < KSYM_NAME_LEN); | |
304 | name = kallsyms_lookup(address, &size, &offset, | |
305 | &modname, buf); | |
306 | if (name == NULL) { | |
307 | buf[0] = '\0'; | |
308 | return; | |
309 | } | |
310 | namelen = strlen(buf); | |
311 | remaining = (bufsize - 1) - namelen; | |
312 | p = buf + namelen; | |
313 | rc = snprintf(p, remaining, "+%#lx/%#lx ", | |
314 | offset + adjust, size); | |
315 | if (modname && rc < remaining) | |
316 | snprintf(p + rc, remaining - rc, "[%s] ", modname); | |
317 | buf[bufsize-1] = '\0'; | |
318 | return; | |
319 | } | |
320 | ||
321 | /* If we don't have the mmap_sem, we can't show any more info. */ | |
322 | buf[0] = '\0'; | |
323 | if (!have_mmap_sem) | |
324 | return; | |
325 | ||
326 | /* Find vma info. */ | |
327 | vma = find_vma(kbt->task->mm, address); | |
328 | if (vma == NULL || address < vma->vm_start) { | |
329 | snprintf(buf, bufsize, "[unmapped address] "); | |
330 | return; | |
331 | } | |
332 | ||
333 | if (vma->vm_file) { | |
9bf39ab2 | 334 | p = file_path(vma->vm_file, buf, bufsize); |
5f639fdc CM |
335 | if (IS_ERR(p)) |
336 | p = "?"; | |
0cc96a74 | 337 | name = kbasename(p); |
5f639fdc | 338 | } else { |
0cc96a74 | 339 | name = "anon"; |
5f639fdc CM |
340 | } |
341 | ||
342 | /* Generate a string description of the vma info. */ | |
0cc96a74 | 343 | namelen = strlen(name); |
5f639fdc | 344 | remaining = (bufsize - 1) - namelen; |
0cc96a74 | 345 | memmove(buf, name, namelen); |
5f639fdc CM |
346 | snprintf(buf + namelen, remaining, "[%lx+%lx] ", |
347 | vma->vm_start, vma->vm_end - vma->vm_start); | |
348 | } | |
349 | ||
3ef23111 CM |
350 | /* |
351 | * Avoid possible crash recursion during backtrace. If it happens, it | |
352 | * makes it easy to lose the actual root cause of the failure, so we | |
353 | * put a simple guard on all the backtrace loops. | |
354 | */ | |
355 | static bool start_backtrace(void) | |
356 | { | |
47ad7b9b | 357 | if (current_thread_info()->in_backtrace) { |
3ef23111 CM |
358 | pr_err("Backtrace requested while in backtrace!\n"); |
359 | return false; | |
360 | } | |
47ad7b9b | 361 | current_thread_info()->in_backtrace = true; |
3ef23111 CM |
362 | return true; |
363 | } | |
364 | ||
365 | static void end_backtrace(void) | |
366 | { | |
47ad7b9b | 367 | current_thread_info()->in_backtrace = false; |
3ef23111 CM |
368 | } |
369 | ||
867e359b CM |
370 | /* |
371 | * This method wraps the backtracer's more generic support. | |
372 | * It is only invoked from the architecture-specific code; show_stack() | |
47ad7b9b | 373 | * and dump_stack() are architecture-independent entry points. |
867e359b | 374 | */ |
47ad7b9b | 375 | void tile_show_stack(struct KBacktraceIterator *kbt) |
867e359b CM |
376 | { |
377 | int i; | |
5f639fdc | 378 | int have_mmap_sem = 0; |
867e359b | 379 | |
3ef23111 CM |
380 | if (!start_backtrace()) |
381 | return; | |
867e359b CM |
382 | kbt->verbose = 1; |
383 | i = 0; | |
384 | for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) { | |
867e359b | 385 | char namebuf[KSYM_NAME_LEN+100]; |
5f639fdc | 386 | unsigned long address = kbt->it.pc; |
867e359b | 387 | |
47ad7b9b CM |
388 | /* |
389 | * Try to acquire the mmap_sem as we pass into userspace. | |
390 | * If we're in an interrupt context, don't even try, since | |
391 | * it's not safe to call e.g. d_path() from an interrupt, | |
392 | * since it uses spin locks without disabling interrupts. | |
393 | * Note we test "kbt->task == current", not "kbt->is_current", | |
394 | * since we're checking that "current" will work in d_path(). | |
395 | */ | |
396 | if (kbt->task == current && address < PAGE_OFFSET && | |
397 | !have_mmap_sem && kbt->task->mm && !in_interrupt()) { | |
5f639fdc CM |
398 | have_mmap_sem = |
399 | down_read_trylock(&kbt->task->mm->mmap_sem); | |
47ad7b9b | 400 | } |
5f639fdc CM |
401 | |
402 | describe_addr(kbt, address, have_mmap_sem, | |
403 | namebuf, sizeof(namebuf)); | |
867e359b | 404 | |
0707ad30 | 405 | pr_err(" frame %d: 0x%lx %s(sp 0x%lx)\n", |
867e359b CM |
406 | i++, address, namebuf, (unsigned long)(kbt->it.sp)); |
407 | ||
408 | if (i >= 100) { | |
f4743673 | 409 | pr_err("Stack dump truncated (%d frames)\n", i); |
867e359b CM |
410 | break; |
411 | } | |
412 | } | |
dabe98c9 CM |
413 | if (kbt->end == KBT_LOOP) |
414 | pr_err("Stack dump stopped; next frame identical to this one\n"); | |
5f639fdc CM |
415 | if (have_mmap_sem) |
416 | up_read(&kbt->task->mm->mmap_sem); | |
3ef23111 | 417 | end_backtrace(); |
867e359b CM |
418 | } |
419 | EXPORT_SYMBOL(tile_show_stack); | |
420 | ||
867e359b CM |
421 | static struct pt_regs *regs_to_pt_regs(struct pt_regs *regs, |
422 | ulong pc, ulong lr, ulong sp, ulong r52) | |
423 | { | |
424 | memset(regs, 0, sizeof(struct pt_regs)); | |
425 | regs->pc = pc; | |
426 | regs->lr = lr; | |
427 | regs->sp = sp; | |
428 | regs->regs[52] = r52; | |
429 | return regs; | |
430 | } | |
431 | ||
47ad7b9b | 432 | /* Deprecated function currently only used by kernel_double_fault(). */ |
867e359b CM |
433 | void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52) |
434 | { | |
47ad7b9b | 435 | struct KBacktraceIterator kbt; |
867e359b | 436 | struct pt_regs regs; |
47ad7b9b CM |
437 | |
438 | regs_to_pt_regs(®s, pc, lr, sp, r52); | |
439 | KBacktraceIterator_init(&kbt, NULL, ®s); | |
440 | tile_show_stack(&kbt); | |
867e359b CM |
441 | } |
442 | ||
443 | /* This is called from KBacktraceIterator_init_current() */ | |
444 | void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt, ulong pc, | |
445 | ulong lr, ulong sp, ulong r52) | |
446 | { | |
447 | struct pt_regs regs; | |
448 | KBacktraceIterator_init(kbt, NULL, | |
449 | regs_to_pt_regs(®s, pc, lr, sp, r52)); | |
450 | } | |
451 | ||
47ad7b9b CM |
452 | /* |
453 | * Called from sched_show_task() with task != NULL, or dump_stack() | |
454 | * with task == NULL. The esp argument is always NULL. | |
455 | */ | |
867e359b CM |
456 | void show_stack(struct task_struct *task, unsigned long *esp) |
457 | { | |
458 | struct KBacktraceIterator kbt; | |
47ad7b9b | 459 | if (task == NULL || task == current) { |
867e359b | 460 | KBacktraceIterator_init_current(&kbt); |
47ad7b9b CM |
461 | KBacktraceIterator_next(&kbt); /* don't show first frame */ |
462 | } else { | |
867e359b | 463 | KBacktraceIterator_init(&kbt, task, NULL); |
47ad7b9b CM |
464 | } |
465 | tile_show_stack(&kbt); | |
867e359b CM |
466 | } |
467 | ||
468 | #ifdef CONFIG_STACKTRACE | |
469 | ||
470 | /* Support generic Linux stack API too */ | |
471 | ||
47ad7b9b CM |
472 | static void save_stack_trace_common(struct task_struct *task, |
473 | struct pt_regs *regs, | |
474 | bool user, | |
475 | struct stack_trace *trace) | |
867e359b CM |
476 | { |
477 | struct KBacktraceIterator kbt; | |
478 | int skip = trace->skip; | |
479 | int i = 0; | |
480 | ||
3ef23111 CM |
481 | if (!start_backtrace()) |
482 | goto done; | |
47ad7b9b CM |
483 | if (regs != NULL) { |
484 | KBacktraceIterator_init(&kbt, NULL, regs); | |
485 | } else if (task == NULL || task == current) { | |
867e359b | 486 | KBacktraceIterator_init_current(&kbt); |
47ad7b9b CM |
487 | skip++; /* don't show KBacktraceIterator_init_current */ |
488 | } else { | |
867e359b | 489 | KBacktraceIterator_init(&kbt, task, NULL); |
47ad7b9b | 490 | } |
867e359b CM |
491 | for (; !KBacktraceIterator_end(&kbt); KBacktraceIterator_next(&kbt)) { |
492 | if (skip) { | |
493 | --skip; | |
494 | continue; | |
495 | } | |
47ad7b9b CM |
496 | if (i >= trace->max_entries || |
497 | (!user && kbt.it.pc < PAGE_OFFSET)) | |
867e359b CM |
498 | break; |
499 | trace->entries[i++] = kbt.it.pc; | |
500 | } | |
3ef23111 CM |
501 | end_backtrace(); |
502 | done: | |
47ad7b9b CM |
503 | if (i < trace->max_entries) |
504 | trace->entries[i++] = ULONG_MAX; | |
867e359b CM |
505 | trace->nr_entries = i; |
506 | } | |
47ad7b9b CM |
507 | |
508 | void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace) | |
509 | { | |
510 | save_stack_trace_common(task, NULL, false, trace); | |
511 | } | |
867e359b CM |
512 | EXPORT_SYMBOL(save_stack_trace_tsk); |
513 | ||
514 | void save_stack_trace(struct stack_trace *trace) | |
515 | { | |
47ad7b9b | 516 | save_stack_trace_common(NULL, NULL, false, trace); |
867e359b | 517 | } |
7c63e1ee | 518 | EXPORT_SYMBOL_GPL(save_stack_trace); |
867e359b | 519 | |
47ad7b9b CM |
520 | void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) |
521 | { | |
522 | save_stack_trace_common(NULL, regs, false, trace); | |
523 | } | |
524 | ||
525 | void save_stack_trace_user(struct stack_trace *trace) | |
526 | { | |
527 | /* Trace user stack if we are not a kernel thread. */ | |
528 | if (current->mm) | |
529 | save_stack_trace_common(NULL, task_pt_regs(current), | |
530 | true, trace); | |
531 | else if (trace->nr_entries < trace->max_entries) | |
532 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
533 | } | |
867e359b CM |
534 | #endif |
535 | ||
536 | /* In entry.S */ | |
537 | EXPORT_SYMBOL(KBacktraceIterator_init_current); |