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