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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>
13#include <linux/sched/debug.h>
14#include <linux/sched/task_stack.h>
15#include <linux/ftrace.h>
16#include <linux/kexec.h>
17#include <linux/bug.h>
18#include <linux/nmi.h>
19#include <linux/sysfs.h>
20
21#include <asm/cpu_entry_area.h>
22#include <asm/stacktrace.h>
23#include <asm/unwind.h>
24
25int panic_on_unrecovered_nmi;
26int panic_on_io_nmi;
27static unsigned int code_bytes = 64;
28static int die_counter;
29
30bool 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
47bool in_entry_stack(unsigned long *stack, struct stack_info *info)
48{
49 struct entry_stack *ss = cpu_entry_stack(smp_processor_id());
50
51 void *begin = ss;
52 void *end = ss + 1;
53
54 if ((void *)stack < begin || (void *)stack >= end)
55 return false;
56
57 info->type = STACK_TYPE_ENTRY;
58 info->begin = begin;
59 info->end = end;
60 info->next_sp = NULL;
61
62 return true;
63}
64
65static void printk_stack_address(unsigned long address, int reliable,
66 char *log_lvl)
67{
68 touch_nmi_watchdog();
69 printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
70}
71
72void 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
79static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
80 bool partial)
81{
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))) {
92 __show_regs(regs, 0);
93
94 } else if (partial && on_stack(info, (void *)regs + IRET_FRAME_OFFSET,
95 IRET_FRAME_SIZE)) {
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
105void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
106 unsigned long *stack, char *log_lvl)
107{
108 struct unwind_state state;
109 struct stack_info stack_info = {0};
110 unsigned long visit_mask = 0;
111 int graph_idx = 0;
112 bool partial = false;
113
114 printk("%sCall Trace:\n", log_lvl);
115
116 unwind_start(&state, task, regs, stack);
117 stack = stack ? : get_stack_pointer(task, regs);
118 regs = unwind_get_entry_regs(&state, &partial);
119
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)
128 * - entry stack
129 *
130 * x86-32 can have up to four stacks:
131 * - task stack
132 * - softirq stack
133 * - hardirq stack
134 * - entry stack
135 */
136 for ( ; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
137 const char *stack_name;
138
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 }
150
151 stack_name = stack_type_name(stack_info.type);
152 if (stack_name)
153 printk("%s <%s>\n", log_lvl, stack_name);
154
155 if (regs)
156 show_regs_if_on_stack(&stack_info, regs, partial);
157
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;
171 unsigned long addr = READ_ONCE_NOCHECK(*stack);
172 unsigned long *ret_addr_p =
173 unwind_get_return_address_ptr(&state);
174
175 if (!__kernel_text_address(addr))
176 continue;
177
178 /*
179 * Don't print regs->ip again if it was already printed
180 * by show_regs_if_on_stack().
181 */
182 if (regs && stack == ®s->ip)
183 goto next;
184
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
206next:
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);
213
214 /* if the frame has entry regs, print them */
215 regs = unwind_get_entry_regs(&state, &partial);
216 if (regs)
217 show_regs_if_on_stack(&stack_info, regs, partial);
218 }
219
220 if (stack_name)
221 printk("%s </%s>\n", log_lvl, stack_name);
222 }
223}
224
225void show_stack(struct task_struct *task, unsigned long *sp)
226{
227 task = task ? : current;
228
229 /*
230 * Stack frames below this one aren't interesting. Don't show them
231 * if we're printing for %current.
232 */
233 if (!sp && task == current)
234 sp = get_stack_pointer(current, NULL);
235
236 show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT);
237}
238
239void show_stack_regs(struct pt_regs *regs)
240{
241 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
242}
243
244static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
245static int die_owner = -1;
246static unsigned int die_nest_count;
247
248unsigned long oops_begin(void)
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();
258 if (!arch_spin_trylock(&die_lock)) {
259 if (cpu == die_owner)
260 /* nested oops. should stop eventually */;
261 else
262 arch_spin_lock(&die_lock);
263 }
264 die_nest_count++;
265 die_owner = cpu;
266 console_verbose();
267 bust_spinlocks(1);
268 return flags;
269}
270EXPORT_SYMBOL_GPL(oops_begin);
271NOKPROBE_SYMBOL(oops_begin);
272
273void __noreturn rewind_stack_do_exit(int signr);
274
275void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
276{
277 if (regs && kexec_should_crash(current))
278 crash_kexec(regs);
279
280 bust_spinlocks(0);
281 die_owner = -1;
282 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
283 die_nest_count--;
284 if (!die_nest_count)
285 /* Nest count reaches zero, release the lock. */
286 arch_spin_unlock(&die_lock);
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");
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);
303}
304NOKPROBE_SYMBOL(oops_end);
305
306int __die(const char *str, struct pt_regs *regs, long err)
307{
308#ifdef CONFIG_X86_32
309 unsigned short ss;
310 unsigned long sp;
311#endif
312 printk(KERN_DEFAULT
313 "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
314 IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
315 IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
316 debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
317 IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "",
318 IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ?
319 (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
320
321 if (notify_die(DIE_OOPS, str, regs, err,
322 current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
323 return 1;
324
325 print_modules();
326 show_regs(regs);
327#ifdef CONFIG_X86_32
328 if (user_mode(regs)) {
329 sp = regs->sp;
330 ss = regs->ss;
331 } else {
332 sp = kernel_stack_pointer(regs);
333 savesegment(ss, ss);
334 }
335 printk(KERN_EMERG "EIP: %pS SS:ESP: %04x:%08lx\n",
336 (void *)regs->ip, ss, sp);
337#else
338 /* Executive summary in case the oops scrolled away */
339 printk(KERN_ALERT "RIP: %pS RSP: %016lx\n", (void *)regs->ip, regs->sp);
340#endif
341 return 0;
342}
343NOKPROBE_SYMBOL(__die);
344
345/*
346 * This is gone through when something in the kernel has done something bad
347 * and is about to be terminated:
348 */
349void die(const char *str, struct pt_regs *regs, long err)
350{
351 unsigned long flags = oops_begin();
352 int sig = SIGSEGV;
353
354 if (__die(str, regs, err))
355 sig = 0;
356 oops_end(flags, regs, sig);
357}
358
359static int __init code_bytes_setup(char *s)
360{
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;
372 if (code_bytes > 8192)
373 code_bytes = 8192;
374
375 return 1;
376}
377__setup("code_bytes=", code_bytes_setup);
378
379void show_regs(struct pt_regs *regs)
380{
381 bool all = true;
382 int i;
383
384 show_regs_print_info(KERN_DEFAULT);
385
386 if (IS_ENABLED(CONFIG_X86_32))
387 all = !user_mode(regs);
388
389 __show_regs(regs, all);
390
391 /*
392 * When in-kernel, we also print out the stack and code at the
393 * time of the fault..
394 */
395 if (!user_mode(regs)) {
396 unsigned int code_prologue = code_bytes * 43 / 64;
397 unsigned int code_len = code_bytes;
398 unsigned char c;
399 u8 *ip;
400
401 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
402
403 printk(KERN_DEFAULT "Code: ");
404
405 ip = (u8 *)regs->ip - code_prologue;
406 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
407 /* try starting at IP */
408 ip = (u8 *)regs->ip;
409 code_len = code_len - code_prologue + 1;
410 }
411 for (i = 0; i < code_len; i++, ip++) {
412 if (ip < (u8 *)PAGE_OFFSET ||
413 probe_kernel_address(ip, c)) {
414 pr_cont(" Bad RIP value.");
415 break;
416 }
417 if (ip == (u8 *)regs->ip)
418 pr_cont("<%02x> ", c);
419 else
420 pr_cont("%02x ", c);
421 }
422 }
423 pr_cont("\n");
424}
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>
13#include <linux/sched/debug.h>
14#include <linux/sched/task_stack.h>
15#include <linux/ftrace.h>
16#include <linux/kexec.h>
17#include <linux/bug.h>
18#include <linux/nmi.h>
19#include <linux/sysfs.h>
20#include <linux/kasan.h>
21
22#include <asm/cpu_entry_area.h>
23#include <asm/stacktrace.h>
24#include <asm/unwind.h>
25
26int panic_on_unrecovered_nmi;
27int panic_on_io_nmi;
28static int die_counter;
29
30static struct pt_regs exec_summary_regs;
31
32bool noinstr in_task_stack(unsigned long *stack, struct task_struct *task,
33 struct stack_info *info)
34{
35 unsigned long *begin = task_stack_page(task);
36 unsigned long *end = task_stack_page(task) + THREAD_SIZE;
37
38 if (stack < begin || stack >= end)
39 return false;
40
41 info->type = STACK_TYPE_TASK;
42 info->begin = begin;
43 info->end = end;
44 info->next_sp = NULL;
45
46 return true;
47}
48
49/* Called from get_stack_info_noinstr - so must be noinstr too */
50bool noinstr in_entry_stack(unsigned long *stack, struct stack_info *info)
51{
52 struct entry_stack *ss = cpu_entry_stack(smp_processor_id());
53
54 void *begin = ss;
55 void *end = ss + 1;
56
57 if ((void *)stack < begin || (void *)stack >= end)
58 return false;
59
60 info->type = STACK_TYPE_ENTRY;
61 info->begin = begin;
62 info->end = end;
63 info->next_sp = NULL;
64
65 return true;
66}
67
68static void printk_stack_address(unsigned long address, int reliable,
69 const char *log_lvl)
70{
71 touch_nmi_watchdog();
72 printk("%s %s%pBb\n", log_lvl, reliable ? "" : "? ", (void *)address);
73}
74
75static int copy_code(struct pt_regs *regs, u8 *buf, unsigned long src,
76 unsigned int nbytes)
77{
78 if (!user_mode(regs))
79 return copy_from_kernel_nofault(buf, (u8 *)src, nbytes);
80
81 /* The user space code from other tasks cannot be accessed. */
82 if (regs != task_pt_regs(current))
83 return -EPERM;
84
85 /*
86 * Even if named copy_from_user_nmi() this can be invoked from
87 * other contexts and will not try to resolve a pagefault, which is
88 * the correct thing to do here as this code can be called from any
89 * context.
90 */
91 return copy_from_user_nmi(buf, (void __user *)src, nbytes);
92}
93
94/*
95 * There are a couple of reasons for the 2/3rd prologue, courtesy of Linus:
96 *
97 * In case where we don't have the exact kernel image (which, if we did, we can
98 * simply disassemble and navigate to the RIP), the purpose of the bigger
99 * prologue is to have more context and to be able to correlate the code from
100 * the different toolchains better.
101 *
102 * In addition, it helps in recreating the register allocation of the failing
103 * kernel and thus make sense of the register dump.
104 *
105 * What is more, the additional complication of a variable length insn arch like
106 * x86 warrants having longer byte sequence before rIP so that the disassembler
107 * can "sync" up properly and find instruction boundaries when decoding the
108 * opcode bytes.
109 *
110 * Thus, the 2/3rds prologue and 64 byte OPCODE_BUFSIZE is just a random
111 * guesstimate in attempt to achieve all of the above.
112 */
113void show_opcodes(struct pt_regs *regs, const char *loglvl)
114{
115#define PROLOGUE_SIZE 42
116#define EPILOGUE_SIZE 21
117#define OPCODE_BUFSIZE (PROLOGUE_SIZE + 1 + EPILOGUE_SIZE)
118 u8 opcodes[OPCODE_BUFSIZE];
119 unsigned long prologue = regs->ip - PROLOGUE_SIZE;
120
121 switch (copy_code(regs, opcodes, prologue, sizeof(opcodes))) {
122 case 0:
123 printk("%sCode: %" __stringify(PROLOGUE_SIZE) "ph <%02x> %"
124 __stringify(EPILOGUE_SIZE) "ph\n", loglvl, opcodes,
125 opcodes[PROLOGUE_SIZE], opcodes + PROLOGUE_SIZE + 1);
126 break;
127 case -EPERM:
128 /* No access to the user space stack of other tasks. Ignore. */
129 break;
130 default:
131 printk("%sCode: Unable to access opcode bytes at 0x%lx.\n",
132 loglvl, prologue);
133 break;
134 }
135}
136
137void show_ip(struct pt_regs *regs, const char *loglvl)
138{
139#ifdef CONFIG_X86_32
140 printk("%sEIP: %pS\n", loglvl, (void *)regs->ip);
141#else
142 printk("%sRIP: %04x:%pS\n", loglvl, (int)regs->cs, (void *)regs->ip);
143#endif
144 show_opcodes(regs, loglvl);
145}
146
147void show_iret_regs(struct pt_regs *regs, const char *log_lvl)
148{
149 show_ip(regs, log_lvl);
150 printk("%sRSP: %04x:%016lx EFLAGS: %08lx", log_lvl, (int)regs->ss,
151 regs->sp, regs->flags);
152}
153
154static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
155 bool partial, const char *log_lvl)
156{
157 /*
158 * These on_stack() checks aren't strictly necessary: the unwind code
159 * has already validated the 'regs' pointer. The checks are done for
160 * ordering reasons: if the registers are on the next stack, we don't
161 * want to print them out yet. Otherwise they'll be shown as part of
162 * the wrong stack. Later, when show_trace_log_lvl() switches to the
163 * next stack, this function will be called again with the same regs so
164 * they can be printed in the right context.
165 */
166 if (!partial && on_stack(info, regs, sizeof(*regs))) {
167 __show_regs(regs, SHOW_REGS_SHORT, log_lvl);
168
169 } else if (partial && on_stack(info, (void *)regs + IRET_FRAME_OFFSET,
170 IRET_FRAME_SIZE)) {
171 /*
172 * When an interrupt or exception occurs in entry code, the
173 * full pt_regs might not have been saved yet. In that case
174 * just print the iret frame.
175 */
176 show_iret_regs(regs, log_lvl);
177 }
178}
179
180/*
181 * This function reads pointers from the stack and dereferences them. The
182 * pointers may not have their KMSAN shadow set up properly, which may result
183 * in false positive reports. Disable instrumentation to avoid those.
184 */
185__no_kmsan_checks
186static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
187 unsigned long *stack, const char *log_lvl)
188{
189 struct unwind_state state;
190 struct stack_info stack_info = {0};
191 unsigned long visit_mask = 0;
192 int graph_idx = 0;
193 bool partial = false;
194
195 printk("%sCall Trace:\n", log_lvl);
196
197 unwind_start(&state, task, regs, stack);
198 stack = stack ? : get_stack_pointer(task, regs);
199 regs = unwind_get_entry_regs(&state, &partial);
200
201 /*
202 * Iterate through the stacks, starting with the current stack pointer.
203 * Each stack has a pointer to the next one.
204 *
205 * x86-64 can have several stacks:
206 * - task stack
207 * - interrupt stack
208 * - HW exception stacks (double fault, nmi, debug, mce)
209 * - entry stack
210 *
211 * x86-32 can have up to four stacks:
212 * - task stack
213 * - softirq stack
214 * - hardirq stack
215 * - entry stack
216 */
217 for ( ; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
218 const char *stack_name;
219
220 if (get_stack_info(stack, task, &stack_info, &visit_mask)) {
221 /*
222 * We weren't on a valid stack. It's possible that
223 * we overflowed a valid stack into a guard page.
224 * See if the next page up is valid so that we can
225 * generate some kind of backtrace if this happens.
226 */
227 stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack);
228 if (get_stack_info(stack, task, &stack_info, &visit_mask))
229 break;
230 }
231
232 stack_name = stack_type_name(stack_info.type);
233 if (stack_name)
234 printk("%s <%s>\n", log_lvl, stack_name);
235
236 if (regs)
237 show_regs_if_on_stack(&stack_info, regs, partial, log_lvl);
238
239 /*
240 * Scan the stack, printing any text addresses we find. At the
241 * same time, follow proper stack frames with the unwinder.
242 *
243 * Addresses found during the scan which are not reported by
244 * the unwinder are considered to be additional clues which are
245 * sometimes useful for debugging and are prefixed with '?'.
246 * This also serves as a failsafe option in case the unwinder
247 * goes off in the weeds.
248 */
249 for (; stack < stack_info.end; stack++) {
250 unsigned long real_addr;
251 int reliable = 0;
252 unsigned long addr = READ_ONCE_NOCHECK(*stack);
253 unsigned long *ret_addr_p =
254 unwind_get_return_address_ptr(&state);
255
256 if (!__kernel_text_address(addr))
257 continue;
258
259 /*
260 * Don't print regs->ip again if it was already printed
261 * by show_regs_if_on_stack().
262 */
263 if (regs && stack == ®s->ip)
264 goto next;
265
266 if (stack == ret_addr_p)
267 reliable = 1;
268
269 /*
270 * When function graph tracing is enabled for a
271 * function, its return address on the stack is
272 * replaced with the address of an ftrace handler
273 * (return_to_handler). In that case, before printing
274 * the "real" address, we want to print the handler
275 * address as an "unreliable" hint that function graph
276 * tracing was involved.
277 */
278 real_addr = ftrace_graph_ret_addr(task, &graph_idx,
279 addr, stack);
280 if (real_addr != addr)
281 printk_stack_address(addr, 0, log_lvl);
282 printk_stack_address(real_addr, reliable, log_lvl);
283
284 if (!reliable)
285 continue;
286
287next:
288 /*
289 * Get the next frame from the unwinder. No need to
290 * check for an error: if anything goes wrong, the rest
291 * of the addresses will just be printed as unreliable.
292 */
293 unwind_next_frame(&state);
294
295 /* if the frame has entry regs, print them */
296 regs = unwind_get_entry_regs(&state, &partial);
297 if (regs)
298 show_regs_if_on_stack(&stack_info, regs, partial, log_lvl);
299 }
300
301 if (stack_name)
302 printk("%s </%s>\n", log_lvl, stack_name);
303 }
304}
305
306void show_stack(struct task_struct *task, unsigned long *sp,
307 const char *loglvl)
308{
309 task = task ? : current;
310
311 /*
312 * Stack frames below this one aren't interesting. Don't show them
313 * if we're printing for %current.
314 */
315 if (!sp && task == current)
316 sp = get_stack_pointer(current, NULL);
317
318 show_trace_log_lvl(task, NULL, sp, loglvl);
319}
320
321void show_stack_regs(struct pt_regs *regs)
322{
323 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
324}
325
326static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
327static int die_owner = -1;
328static unsigned int die_nest_count;
329
330unsigned long oops_begin(void)
331{
332 int cpu;
333 unsigned long flags;
334
335 oops_enter();
336
337 /* racy, but better than risking deadlock. */
338 raw_local_irq_save(flags);
339 cpu = smp_processor_id();
340 if (!arch_spin_trylock(&die_lock)) {
341 if (cpu == die_owner)
342 /* nested oops. should stop eventually */;
343 else
344 arch_spin_lock(&die_lock);
345 }
346 die_nest_count++;
347 die_owner = cpu;
348 console_verbose();
349 bust_spinlocks(1);
350 return flags;
351}
352NOKPROBE_SYMBOL(oops_begin);
353
354void __noreturn rewind_stack_and_make_dead(int signr);
355
356void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
357{
358 if (regs && kexec_should_crash(current))
359 crash_kexec(regs);
360
361 bust_spinlocks(0);
362 die_owner = -1;
363 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
364 die_nest_count--;
365 if (!die_nest_count)
366 /* Nest count reaches zero, release the lock. */
367 arch_spin_unlock(&die_lock);
368 raw_local_irq_restore(flags);
369 oops_exit();
370
371 /* Executive summary in case the oops scrolled away */
372 __show_regs(&exec_summary_regs, SHOW_REGS_ALL, KERN_DEFAULT);
373
374 if (!signr)
375 return;
376 if (in_interrupt())
377 panic("Fatal exception in interrupt");
378 if (panic_on_oops)
379 panic("Fatal exception");
380
381 /*
382 * We're not going to return, but we might be on an IST stack or
383 * have very little stack space left. Rewind the stack and kill
384 * the task.
385 * Before we rewind the stack, we have to tell KASAN that we're going to
386 * reuse the task stack and that existing poisons are invalid.
387 */
388 kasan_unpoison_task_stack(current);
389 rewind_stack_and_make_dead(signr);
390}
391NOKPROBE_SYMBOL(oops_end);
392
393static void __die_header(const char *str, struct pt_regs *regs, long err)
394{
395 const char *pr = "";
396
397 /* Save the regs of the first oops for the executive summary later. */
398 if (!die_counter)
399 exec_summary_regs = *regs;
400
401 if (IS_ENABLED(CONFIG_PREEMPTION))
402 pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
403
404 printk(KERN_DEFAULT
405 "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
406 pr,
407 IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
408 debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
409 IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "",
410 IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ?
411 (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
412}
413NOKPROBE_SYMBOL(__die_header);
414
415static int __die_body(const char *str, struct pt_regs *regs, long err)
416{
417 show_regs(regs);
418 print_modules();
419
420 if (notify_die(DIE_OOPS, str, regs, err,
421 current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
422 return 1;
423
424 return 0;
425}
426NOKPROBE_SYMBOL(__die_body);
427
428int __die(const char *str, struct pt_regs *regs, long err)
429{
430 __die_header(str, regs, err);
431 return __die_body(str, regs, err);
432}
433NOKPROBE_SYMBOL(__die);
434
435/*
436 * This is gone through when something in the kernel has done something bad
437 * and is about to be terminated:
438 */
439void die(const char *str, struct pt_regs *regs, long err)
440{
441 unsigned long flags = oops_begin();
442 int sig = SIGSEGV;
443
444 if (__die(str, regs, err))
445 sig = 0;
446 oops_end(flags, regs, sig);
447}
448
449void die_addr(const char *str, struct pt_regs *regs, long err, long gp_addr)
450{
451 unsigned long flags = oops_begin();
452 int sig = SIGSEGV;
453
454 __die_header(str, regs, err);
455 if (gp_addr)
456 kasan_non_canonical_hook(gp_addr);
457 if (__die_body(str, regs, err))
458 sig = 0;
459 oops_end(flags, regs, sig);
460}
461
462void show_regs(struct pt_regs *regs)
463{
464 enum show_regs_mode print_kernel_regs;
465
466 show_regs_print_info(KERN_DEFAULT);
467
468 print_kernel_regs = user_mode(regs) ? SHOW_REGS_USER : SHOW_REGS_ALL;
469 __show_regs(regs, print_kernel_regs, KERN_DEFAULT);
470
471 /*
472 * When in-kernel, we also print out the stack at the time of the fault..
473 */
474 if (!user_mode(regs))
475 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
476}