Commit | Line | Data |
---|---|---|
878719e8 NH |
1 | /* |
2 | * Copyright (C) 1991, 1992 Linus Torvalds | |
3 | * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs | |
4 | */ | |
5 | #include <linux/kallsyms.h> | |
6 | #include <linux/kprobes.h> | |
7 | #include <linux/uaccess.h> | |
8 | #include <linux/utsname.h> | |
9 | #include <linux/hardirq.h> | |
10 | #include <linux/kdebug.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/ptrace.h> | |
b17b0153 | 13 | #include <linux/sched/debug.h> |
68db0cf1 | 14 | #include <linux/sched/task_stack.h> |
712406a6 | 15 | #include <linux/ftrace.h> |
878719e8 NH |
16 | #include <linux/kexec.h> |
17 | #include <linux/bug.h> | |
18 | #include <linux/nmi.h> | |
19 | #include <linux/sysfs.h> | |
20 | ||
92a0f81d | 21 | #include <asm/cpu_entry_area.h> |
878719e8 | 22 | #include <asm/stacktrace.h> |
e18bcccd | 23 | #include <asm/unwind.h> |
878719e8 NH |
24 | |
25 | int panic_on_unrecovered_nmi; | |
5211a242 | 26 | int panic_on_io_nmi; |
878719e8 | 27 | unsigned int code_bytes = 64; |
878719e8 NH |
28 | static int die_counter; |
29 | ||
cb76c939 JP |
30 | bool in_task_stack(unsigned long *stack, struct task_struct *task, |
31 | struct stack_info *info) | |
32 | { | |
33 | unsigned long *begin = task_stack_page(task); | |
34 | unsigned long *end = task_stack_page(task) + THREAD_SIZE; | |
35 | ||
36 | if (stack < begin || stack >= end) | |
37 | return false; | |
38 | ||
39 | info->type = STACK_TYPE_TASK; | |
40 | info->begin = begin; | |
41 | info->end = end; | |
42 | info->next_sp = NULL; | |
43 | ||
44 | return true; | |
45 | } | |
46 | ||
4fe2d8b1 | 47 | bool in_entry_stack(unsigned long *stack, struct stack_info *info) |
33a2f1a6 | 48 | { |
4fe2d8b1 | 49 | struct entry_stack *ss = cpu_entry_stack(smp_processor_id()); |
33a2f1a6 | 50 | |
0f9a4810 AL |
51 | void *begin = ss; |
52 | void *end = ss + 1; | |
33a2f1a6 AL |
53 | |
54 | if ((void *)stack < begin || (void *)stack >= end) | |
55 | return false; | |
56 | ||
4fe2d8b1 | 57 | info->type = STACK_TYPE_ENTRY; |
33a2f1a6 AL |
58 | info->begin = begin; |
59 | info->end = end; | |
60 | info->next_sp = NULL; | |
61 | ||
62 | return true; | |
63 | } | |
64 | ||
1fc7f61c | 65 | static void printk_stack_address(unsigned long address, int reliable, |
d438f5fd | 66 | char *log_lvl) |
878719e8 | 67 | { |
d438f5fd | 68 | touch_nmi_watchdog(); |
bb5e5ce5 | 69 | printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address); |
5f01c988 JS |
70 | } |
71 | ||
b02fcf9b JP |
72 | void show_iret_regs(struct pt_regs *regs) |
73 | { | |
74 | printk(KERN_DEFAULT "RIP: %04x:%pS\n", (int)regs->cs, (void *)regs->ip); | |
75 | printk(KERN_DEFAULT "RSP: %04x:%016lx EFLAGS: %08lx", (int)regs->ss, | |
76 | regs->sp, regs->flags); | |
77 | } | |
78 | ||
a9cdbe72 JP |
79 | static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs, |
80 | bool partial) | |
b02fcf9b | 81 | { |
a9cdbe72 JP |
82 | /* |
83 | * These on_stack() checks aren't strictly necessary: the unwind code | |
84 | * has already validated the 'regs' pointer. The checks are done for | |
85 | * ordering reasons: if the registers are on the next stack, we don't | |
86 | * want to print them out yet. Otherwise they'll be shown as part of | |
87 | * the wrong stack. Later, when show_trace_log_lvl() switches to the | |
88 | * next stack, this function will be called again with the same regs so | |
89 | * they can be printed in the right context. | |
90 | */ | |
91 | if (!partial && on_stack(info, regs, sizeof(*regs))) { | |
b02fcf9b | 92 | __show_regs(regs, 0); |
a9cdbe72 JP |
93 | |
94 | } else if (partial && on_stack(info, (void *)regs + IRET_FRAME_OFFSET, | |
95 | IRET_FRAME_SIZE)) { | |
b02fcf9b JP |
96 | /* |
97 | * When an interrupt or exception occurs in entry code, the | |
98 | * full pt_regs might not have been saved yet. In that case | |
99 | * just print the iret frame. | |
100 | */ | |
101 | show_iret_regs(regs); | |
102 | } | |
103 | } | |
104 | ||
e18bcccd JP |
105 | void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, |
106 | unsigned long *stack, char *log_lvl) | |
878719e8 | 107 | { |
e18bcccd JP |
108 | struct unwind_state state; |
109 | struct stack_info stack_info = {0}; | |
110 | unsigned long visit_mask = 0; | |
111 | int graph_idx = 0; | |
a9cdbe72 | 112 | bool partial; |
878719e8 | 113 | |
e18bcccd | 114 | printk("%sCall Trace:\n", log_lvl); |
878719e8 | 115 | |
e18bcccd | 116 | unwind_start(&state, task, regs, stack); |
f4474c9f | 117 | stack = stack ? : get_stack_pointer(task, regs); |
3ffdeb1a | 118 | regs = unwind_get_entry_regs(&state, &partial); |
878719e8 | 119 | |
e18bcccd JP |
120 | /* |
121 | * Iterate through the stacks, starting with the current stack pointer. | |
122 | * Each stack has a pointer to the next one. | |
123 | * | |
124 | * x86-64 can have several stacks: | |
125 | * - task stack | |
126 | * - interrupt stack | |
127 | * - HW exception stacks (double fault, nmi, debug, mce) | |
4fe2d8b1 | 128 | * - entry stack |
e18bcccd | 129 | * |
6e60e583 | 130 | * x86-32 can have up to four stacks: |
e18bcccd JP |
131 | * - task stack |
132 | * - softirq stack | |
133 | * - hardirq stack | |
4fe2d8b1 | 134 | * - entry stack |
e18bcccd | 135 | */ |
3ffdeb1a | 136 | for ( ; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { |
3d02a9c4 | 137 | const char *stack_name; |
e18bcccd | 138 | |
6e60e583 AL |
139 | if (get_stack_info(stack, task, &stack_info, &visit_mask)) { |
140 | /* | |
141 | * We weren't on a valid stack. It's possible that | |
142 | * we overflowed a valid stack into a guard page. | |
143 | * See if the next page up is valid so that we can | |
144 | * generate some kind of backtrace if this happens. | |
145 | */ | |
146 | stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack); | |
147 | if (get_stack_info(stack, task, &stack_info, &visit_mask)) | |
148 | break; | |
149 | } | |
e18bcccd | 150 | |
3d02a9c4 JP |
151 | stack_name = stack_type_name(stack_info.type); |
152 | if (stack_name) | |
153 | printk("%s <%s>\n", log_lvl, stack_name); | |
e18bcccd | 154 | |
b02fcf9b | 155 | if (regs) |
a9cdbe72 | 156 | show_regs_if_on_stack(&stack_info, regs, partial); |
b0529bec | 157 | |
e18bcccd JP |
158 | /* |
159 | * Scan the stack, printing any text addresses we find. At the | |
160 | * same time, follow proper stack frames with the unwinder. | |
161 | * | |
162 | * Addresses found during the scan which are not reported by | |
163 | * the unwinder are considered to be additional clues which are | |
164 | * sometimes useful for debugging and are prefixed with '?'. | |
165 | * This also serves as a failsafe option in case the unwinder | |
166 | * goes off in the weeds. | |
167 | */ | |
168 | for (; stack < stack_info.end; stack++) { | |
169 | unsigned long real_addr; | |
170 | int reliable = 0; | |
91e08ab0 | 171 | unsigned long addr = READ_ONCE_NOCHECK(*stack); |
e18bcccd JP |
172 | unsigned long *ret_addr_p = |
173 | unwind_get_return_address_ptr(&state); | |
174 | ||
175 | if (!__kernel_text_address(addr)) | |
176 | continue; | |
177 | ||
3b3fa11b JP |
178 | /* |
179 | * Don't print regs->ip again if it was already printed | |
a9cdbe72 | 180 | * by show_regs_if_on_stack(). |
3b3fa11b | 181 | */ |
b0529bec JP |
182 | if (regs && stack == ®s->ip) |
183 | goto next; | |
3b3fa11b | 184 | |
e18bcccd JP |
185 | if (stack == ret_addr_p) |
186 | reliable = 1; | |
187 | ||
188 | /* | |
189 | * When function graph tracing is enabled for a | |
190 | * function, its return address on the stack is | |
191 | * replaced with the address of an ftrace handler | |
192 | * (return_to_handler). In that case, before printing | |
193 | * the "real" address, we want to print the handler | |
194 | * address as an "unreliable" hint that function graph | |
195 | * tracing was involved. | |
196 | */ | |
197 | real_addr = ftrace_graph_ret_addr(task, &graph_idx, | |
198 | addr, stack); | |
199 | if (real_addr != addr) | |
200 | printk_stack_address(addr, 0, log_lvl); | |
201 | printk_stack_address(real_addr, reliable, log_lvl); | |
202 | ||
203 | if (!reliable) | |
204 | continue; | |
205 | ||
b0529bec | 206 | next: |
e18bcccd JP |
207 | /* |
208 | * Get the next frame from the unwinder. No need to | |
209 | * check for an error: if anything goes wrong, the rest | |
210 | * of the addresses will just be printed as unreliable. | |
211 | */ | |
212 | unwind_next_frame(&state); | |
3b3fa11b JP |
213 | |
214 | /* if the frame has entry regs, print them */ | |
a9cdbe72 | 215 | regs = unwind_get_entry_regs(&state, &partial); |
b02fcf9b | 216 | if (regs) |
a9cdbe72 | 217 | show_regs_if_on_stack(&stack_info, regs, partial); |
e18bcccd JP |
218 | } |
219 | ||
3d02a9c4 JP |
220 | if (stack_name) |
221 | printk("%s </%s>\n", log_lvl, stack_name); | |
e18bcccd | 222 | } |
878719e8 NH |
223 | } |
224 | ||
878719e8 NH |
225 | void show_stack(struct task_struct *task, unsigned long *sp) |
226 | { | |
81539169 JP |
227 | task = task ? : current; |
228 | ||
a77f2a4e TH |
229 | /* |
230 | * Stack frames below this one aren't interesting. Don't show them | |
231 | * if we're printing for %current. | |
232 | */ | |
e18bcccd | 233 | if (!sp && task == current) |
4b8afafb | 234 | sp = get_stack_pointer(current, NULL); |
a77f2a4e | 235 | |
0ee1dd9f | 236 | show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT); |
878719e8 NH |
237 | } |
238 | ||
81c2949f BP |
239 | void show_stack_regs(struct pt_regs *regs) |
240 | { | |
0ee1dd9f | 241 | show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT); |
81c2949f BP |
242 | } |
243 | ||
edc35bd7 | 244 | static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; |
878719e8 NH |
245 | static int die_owner = -1; |
246 | static unsigned int die_nest_count; | |
247 | ||
9326638c | 248 | unsigned long oops_begin(void) |
878719e8 NH |
249 | { |
250 | int cpu; | |
251 | unsigned long flags; | |
252 | ||
253 | oops_enter(); | |
254 | ||
255 | /* racy, but better than risking deadlock. */ | |
256 | raw_local_irq_save(flags); | |
257 | cpu = smp_processor_id(); | |
0199c4e6 | 258 | if (!arch_spin_trylock(&die_lock)) { |
878719e8 NH |
259 | if (cpu == die_owner) |
260 | /* nested oops. should stop eventually */; | |
261 | else | |
0199c4e6 | 262 | arch_spin_lock(&die_lock); |
878719e8 NH |
263 | } |
264 | die_nest_count++; | |
265 | die_owner = cpu; | |
266 | console_verbose(); | |
267 | bust_spinlocks(1); | |
268 | return flags; | |
269 | } | |
81e88fdc | 270 | EXPORT_SYMBOL_GPL(oops_begin); |
9326638c | 271 | NOKPROBE_SYMBOL(oops_begin); |
878719e8 | 272 | |
2deb4be2 AL |
273 | void __noreturn rewind_stack_do_exit(int signr); |
274 | ||
9326638c | 275 | void oops_end(unsigned long flags, struct pt_regs *regs, int signr) |
878719e8 NH |
276 | { |
277 | if (regs && kexec_should_crash(current)) | |
278 | crash_kexec(regs); | |
279 | ||
280 | bust_spinlocks(0); | |
281 | die_owner = -1; | |
373d4d09 | 282 | add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); |
878719e8 NH |
283 | die_nest_count--; |
284 | if (!die_nest_count) | |
285 | /* Nest count reaches zero, release the lock. */ | |
0199c4e6 | 286 | arch_spin_unlock(&die_lock); |
878719e8 NH |
287 | raw_local_irq_restore(flags); |
288 | oops_exit(); | |
289 | ||
290 | if (!signr) | |
291 | return; | |
292 | if (in_interrupt()) | |
293 | panic("Fatal exception in interrupt"); | |
294 | if (panic_on_oops) | |
295 | panic("Fatal exception"); | |
2deb4be2 AL |
296 | |
297 | /* | |
298 | * We're not going to return, but we might be on an IST stack or | |
299 | * have very little stack space left. Rewind the stack and kill | |
300 | * the task. | |
301 | */ | |
302 | rewind_stack_do_exit(signr); | |
878719e8 | 303 | } |
9326638c | 304 | NOKPROBE_SYMBOL(oops_end); |
878719e8 | 305 | |
9326638c | 306 | int __die(const char *str, struct pt_regs *regs, long err) |
878719e8 NH |
307 | { |
308 | #ifdef CONFIG_X86_32 | |
309 | unsigned short ss; | |
310 | unsigned long sp; | |
311 | #endif | |
b0f4c4b3 | 312 | printk(KERN_DEFAULT |
5f26d76c | 313 | "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter, |
8fad7ec5 RV |
314 | IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "", |
315 | IS_ENABLED(CONFIG_SMP) ? " SMP" : "", | |
316 | debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "", | |
5f26d76c VB |
317 | IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "", |
318 | IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ? | |
319 | (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : ""); | |
8fad7ec5 | 320 | |
878719e8 | 321 | if (notify_die(DIE_OOPS, str, regs, err, |
51e7dc70 | 322 | current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP) |
878719e8 NH |
323 | return 1; |
324 | ||
0fa0e2f0 | 325 | print_modules(); |
57da8b96 | 326 | show_regs(regs); |
878719e8 | 327 | #ifdef CONFIG_X86_32 |
f39b6f0e | 328 | if (user_mode(regs)) { |
878719e8 | 329 | sp = regs->sp; |
99504819 | 330 | ss = regs->ss; |
a343c75d PA |
331 | } else { |
332 | sp = kernel_stack_pointer(regs); | |
333 | savesegment(ss, ss); | |
878719e8 | 334 | } |
bb5e5ce5 JP |
335 | printk(KERN_EMERG "EIP: %pS SS:ESP: %04x:%08lx\n", |
336 | (void *)regs->ip, ss, sp); | |
878719e8 NH |
337 | #else |
338 | /* Executive summary in case the oops scrolled away */ | |
bb5e5ce5 | 339 | printk(KERN_ALERT "RIP: %pS RSP: %016lx\n", (void *)regs->ip, regs->sp); |
878719e8 NH |
340 | #endif |
341 | return 0; | |
342 | } | |
9326638c | 343 | NOKPROBE_SYMBOL(__die); |
878719e8 NH |
344 | |
345 | /* | |
346 | * This is gone through when something in the kernel has done something bad | |
347 | * and is about to be terminated: | |
348 | */ | |
349 | void die(const char *str, struct pt_regs *regs, long err) | |
350 | { | |
351 | unsigned long flags = oops_begin(); | |
352 | int sig = SIGSEGV; | |
353 | ||
878719e8 NH |
354 | if (__die(str, regs, err)) |
355 | sig = 0; | |
356 | oops_end(flags, regs, sig); | |
357 | } | |
358 | ||
878719e8 NH |
359 | static int __init code_bytes_setup(char *s) |
360 | { | |
363f7ce3 SK |
361 | ssize_t ret; |
362 | unsigned long val; | |
363 | ||
364 | if (!s) | |
365 | return -EINVAL; | |
366 | ||
367 | ret = kstrtoul(s, 0, &val); | |
368 | if (ret) | |
369 | return ret; | |
370 | ||
371 | code_bytes = val; | |
878719e8 NH |
372 | if (code_bytes > 8192) |
373 | code_bytes = 8192; | |
374 | ||
375 | return 1; | |
376 | } | |
377 | __setup("code_bytes=", code_bytes_setup); |