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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 regs = unwind_get_entry_regs(&state, &partial);
199
200 /*
201 * Iterate through the stacks, starting with the current stack pointer.
202 * Each stack has a pointer to the next one.
203 *
204 * x86-64 can have several stacks:
205 * - task stack
206 * - interrupt stack
207 * - HW exception stacks (double fault, nmi, debug, mce)
208 * - entry stack
209 *
210 * x86-32 can have up to four stacks:
211 * - task stack
212 * - softirq stack
213 * - hardirq stack
214 * - entry stack
215 */
216 for (stack = stack ?: get_stack_pointer(task, regs);
217 stack;
218 stack = stack_info.next_sp) {
219 const char *stack_name;
220
221 stack = PTR_ALIGN(stack, sizeof(long));
222
223 if (get_stack_info(stack, task, &stack_info, &visit_mask)) {
224 /*
225 * We weren't on a valid stack. It's possible that
226 * we overflowed a valid stack into a guard page.
227 * See if the next page up is valid so that we can
228 * generate some kind of backtrace if this happens.
229 */
230 stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack);
231 if (get_stack_info(stack, task, &stack_info, &visit_mask))
232 break;
233 }
234
235 stack_name = stack_type_name(stack_info.type);
236 if (stack_name)
237 printk("%s <%s>\n", log_lvl, stack_name);
238
239 if (regs)
240 show_regs_if_on_stack(&stack_info, regs, partial, log_lvl);
241
242 /*
243 * Scan the stack, printing any text addresses we find. At the
244 * same time, follow proper stack frames with the unwinder.
245 *
246 * Addresses found during the scan which are not reported by
247 * the unwinder are considered to be additional clues which are
248 * sometimes useful for debugging and are prefixed with '?'.
249 * This also serves as a failsafe option in case the unwinder
250 * goes off in the weeds.
251 */
252 for (; stack < stack_info.end; stack++) {
253 unsigned long real_addr;
254 int reliable = 0;
255 unsigned long addr = READ_ONCE_NOCHECK(*stack);
256 unsigned long *ret_addr_p =
257 unwind_get_return_address_ptr(&state);
258
259 if (!__kernel_text_address(addr))
260 continue;
261
262 /*
263 * Don't print regs->ip again if it was already printed
264 * by show_regs_if_on_stack().
265 */
266 if (regs && stack == ®s->ip)
267 goto next;
268
269 if (stack == ret_addr_p)
270 reliable = 1;
271
272 /*
273 * When function graph tracing is enabled for a
274 * function, its return address on the stack is
275 * replaced with the address of an ftrace handler
276 * (return_to_handler). In that case, before printing
277 * the "real" address, we want to print the handler
278 * address as an "unreliable" hint that function graph
279 * tracing was involved.
280 */
281 real_addr = ftrace_graph_ret_addr(task, &graph_idx,
282 addr, stack);
283 if (real_addr != addr)
284 printk_stack_address(addr, 0, log_lvl);
285 printk_stack_address(real_addr, reliable, log_lvl);
286
287 if (!reliable)
288 continue;
289
290next:
291 /*
292 * Get the next frame from the unwinder. No need to
293 * check for an error: if anything goes wrong, the rest
294 * of the addresses will just be printed as unreliable.
295 */
296 unwind_next_frame(&state);
297
298 /* if the frame has entry regs, print them */
299 regs = unwind_get_entry_regs(&state, &partial);
300 if (regs)
301 show_regs_if_on_stack(&stack_info, regs, partial, log_lvl);
302 }
303
304 if (stack_name)
305 printk("%s </%s>\n", log_lvl, stack_name);
306 }
307}
308
309void show_stack(struct task_struct *task, unsigned long *sp,
310 const char *loglvl)
311{
312 task = task ? : current;
313
314 /*
315 * Stack frames below this one aren't interesting. Don't show them
316 * if we're printing for %current.
317 */
318 if (!sp && task == current)
319 sp = get_stack_pointer(current, NULL);
320
321 show_trace_log_lvl(task, NULL, sp, loglvl);
322}
323
324void show_stack_regs(struct pt_regs *regs)
325{
326 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
327}
328
329static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
330static int die_owner = -1;
331static unsigned int die_nest_count;
332
333unsigned long oops_begin(void)
334{
335 int cpu;
336 unsigned long flags;
337
338 oops_enter();
339
340 /* racy, but better than risking deadlock. */
341 raw_local_irq_save(flags);
342 cpu = smp_processor_id();
343 if (!arch_spin_trylock(&die_lock)) {
344 if (cpu == die_owner)
345 /* nested oops. should stop eventually */;
346 else
347 arch_spin_lock(&die_lock);
348 }
349 die_nest_count++;
350 die_owner = cpu;
351 console_verbose();
352 bust_spinlocks(1);
353 return flags;
354}
355NOKPROBE_SYMBOL(oops_begin);
356
357void __noreturn rewind_stack_and_make_dead(int signr);
358
359void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
360{
361 if (regs && kexec_should_crash(current))
362 crash_kexec(regs);
363
364 bust_spinlocks(0);
365 die_owner = -1;
366 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
367 die_nest_count--;
368 if (!die_nest_count)
369 /* Nest count reaches zero, release the lock. */
370 arch_spin_unlock(&die_lock);
371 raw_local_irq_restore(flags);
372 oops_exit();
373
374 /* Executive summary in case the oops scrolled away */
375 __show_regs(&exec_summary_regs, SHOW_REGS_ALL, KERN_DEFAULT);
376
377 if (!signr)
378 return;
379 if (in_interrupt())
380 panic("Fatal exception in interrupt");
381 if (panic_on_oops)
382 panic("Fatal exception");
383
384 /*
385 * We're not going to return, but we might be on an IST stack or
386 * have very little stack space left. Rewind the stack and kill
387 * the task.
388 * Before we rewind the stack, we have to tell KASAN that we're going to
389 * reuse the task stack and that existing poisons are invalid.
390 */
391 kasan_unpoison_task_stack(current);
392 rewind_stack_and_make_dead(signr);
393}
394NOKPROBE_SYMBOL(oops_end);
395
396static void __die_header(const char *str, struct pt_regs *regs, long err)
397{
398 const char *pr = "";
399
400 /* Save the regs of the first oops for the executive summary later. */
401 if (!die_counter)
402 exec_summary_regs = *regs;
403
404 if (IS_ENABLED(CONFIG_PREEMPTION))
405 pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
406
407 printk(KERN_DEFAULT
408 "Oops: %s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff,
409 ++die_counter, pr,
410 IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
411 debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
412 IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "",
413 IS_ENABLED(CONFIG_MITIGATION_PAGE_TABLE_ISOLATION) ?
414 (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
415}
416NOKPROBE_SYMBOL(__die_header);
417
418static int __die_body(const char *str, struct pt_regs *regs, long err)
419{
420 show_regs(regs);
421 print_modules();
422
423 if (notify_die(DIE_OOPS, str, regs, err,
424 current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
425 return 1;
426
427 return 0;
428}
429NOKPROBE_SYMBOL(__die_body);
430
431int __die(const char *str, struct pt_regs *regs, long err)
432{
433 __die_header(str, regs, err);
434 return __die_body(str, regs, err);
435}
436NOKPROBE_SYMBOL(__die);
437
438/*
439 * This is gone through when something in the kernel has done something bad
440 * and is about to be terminated:
441 */
442void die(const char *str, struct pt_regs *regs, long err)
443{
444 unsigned long flags = oops_begin();
445 int sig = SIGSEGV;
446
447 if (__die(str, regs, err))
448 sig = 0;
449 oops_end(flags, regs, sig);
450}
451
452void die_addr(const char *str, struct pt_regs *regs, long err, long gp_addr)
453{
454 unsigned long flags = oops_begin();
455 int sig = SIGSEGV;
456
457 __die_header(str, regs, err);
458 if (gp_addr)
459 kasan_non_canonical_hook(gp_addr);
460 if (__die_body(str, regs, err))
461 sig = 0;
462 oops_end(flags, regs, sig);
463}
464
465void show_regs(struct pt_regs *regs)
466{
467 enum show_regs_mode print_kernel_regs;
468
469 show_regs_print_info(KERN_DEFAULT);
470
471 print_kernel_regs = user_mode(regs) ? SHOW_REGS_USER : SHOW_REGS_ALL;
472 __show_regs(regs, print_kernel_regs, KERN_DEFAULT);
473
474 /*
475 * When in-kernel, we also print out the stack at the time of the fault..
476 */
477 if (!user_mode(regs))
478 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
479}