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