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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/ftrace.h>
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>
20
21
22int panic_on_unrecovered_nmi;
23int panic_on_io_nmi;
24unsigned int code_bytes = 64;
25int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
26static int die_counter;
27
28void printk_address(unsigned long address, int reliable)
29{
30 printk(" [<%p>] %s%pB\n", (void *) address,
31 reliable ? "" : "? ", (void *) address);
32}
33
34#ifdef CONFIG_FUNCTION_GRAPH_TRACER
35static void
36print_ftrace_graph_addr(unsigned long addr, void *data,
37 const struct stacktrace_ops *ops,
38 struct thread_info *tinfo, int *graph)
39{
40 struct task_struct *task;
41 unsigned long ret_addr;
42 int index;
43
44 if (addr != (unsigned long)return_to_handler)
45 return;
46
47 task = tinfo->task;
48 index = task->curr_ret_stack;
49
50 if (!task->ret_stack || index < *graph)
51 return;
52
53 index -= *graph;
54 ret_addr = task->ret_stack[index].ret;
55
56 ops->address(data, ret_addr, 1);
57
58 (*graph)++;
59}
60#else
61static inline void
62print_ftrace_graph_addr(unsigned long addr, void *data,
63 const struct stacktrace_ops *ops,
64 struct thread_info *tinfo, int *graph)
65{ }
66#endif
67
68/*
69 * x86-64 can have up to three kernel stacks:
70 * process stack
71 * interrupt stack
72 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
73 */
74
75static inline int valid_stack_ptr(struct thread_info *tinfo,
76 void *p, unsigned int size, void *end)
77{
78 void *t = tinfo;
79 if (end) {
80 if (p < end && p >= (end-THREAD_SIZE))
81 return 1;
82 else
83 return 0;
84 }
85 return p > t && p < t + THREAD_SIZE - size;
86}
87
88unsigned long
89print_context_stack(struct thread_info *tinfo,
90 unsigned long *stack, unsigned long bp,
91 const struct stacktrace_ops *ops, void *data,
92 unsigned long *end, int *graph)
93{
94 struct stack_frame *frame = (struct stack_frame *)bp;
95
96 while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
97 unsigned long addr;
98
99 addr = *stack;
100 if (__kernel_text_address(addr)) {
101 if ((unsigned long) stack == bp + sizeof(long)) {
102 ops->address(data, addr, 1);
103 frame = frame->next_frame;
104 bp = (unsigned long) frame;
105 } else {
106 ops->address(data, addr, 0);
107 }
108 print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
109 }
110 stack++;
111 }
112 return bp;
113}
114EXPORT_SYMBOL_GPL(print_context_stack);
115
116unsigned long
117print_context_stack_bp(struct thread_info *tinfo,
118 unsigned long *stack, unsigned long bp,
119 const struct stacktrace_ops *ops, void *data,
120 unsigned long *end, int *graph)
121{
122 struct stack_frame *frame = (struct stack_frame *)bp;
123 unsigned long *ret_addr = &frame->return_address;
124
125 while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
126 unsigned long addr = *ret_addr;
127
128 if (!__kernel_text_address(addr))
129 break;
130
131 ops->address(data, addr, 1);
132 frame = frame->next_frame;
133 ret_addr = &frame->return_address;
134 print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
135 }
136
137 return (unsigned long)frame;
138}
139EXPORT_SYMBOL_GPL(print_context_stack_bp);
140
141static int print_trace_stack(void *data, char *name)
142{
143 printk("%s <%s> ", (char *)data, name);
144 return 0;
145}
146
147/*
148 * Print one address/symbol entries per line.
149 */
150static void print_trace_address(void *data, unsigned long addr, int reliable)
151{
152 touch_nmi_watchdog();
153 printk(data);
154 printk_address(addr, reliable);
155}
156
157static const struct stacktrace_ops print_trace_ops = {
158 .stack = print_trace_stack,
159 .address = print_trace_address,
160 .walk_stack = print_context_stack,
161};
162
163void
164show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
165 unsigned long *stack, unsigned long bp, char *log_lvl)
166{
167 printk("%sCall Trace:\n", log_lvl);
168 dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
169}
170
171void show_trace(struct task_struct *task, struct pt_regs *regs,
172 unsigned long *stack, unsigned long bp)
173{
174 show_trace_log_lvl(task, regs, stack, bp, "");
175}
176
177void show_stack(struct task_struct *task, unsigned long *sp)
178{
179 show_stack_log_lvl(task, NULL, sp, 0, "");
180}
181
182/*
183 * The architecture-independent dump_stack generator
184 */
185void dump_stack(void)
186{
187 unsigned long bp;
188 unsigned long stack;
189
190 bp = stack_frame(current, NULL);
191 printk("Pid: %d, comm: %.20s %s %s %.*s\n",
192 current->pid, current->comm, print_tainted(),
193 init_utsname()->release,
194 (int)strcspn(init_utsname()->version, " "),
195 init_utsname()->version);
196 show_trace(NULL, NULL, &stack, bp);
197}
198EXPORT_SYMBOL(dump_stack);
199
200static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
201static int die_owner = -1;
202static unsigned int die_nest_count;
203
204unsigned __kprobes long oops_begin(void)
205{
206 int cpu;
207 unsigned long flags;
208
209 oops_enter();
210
211 /* racy, but better than risking deadlock. */
212 raw_local_irq_save(flags);
213 cpu = smp_processor_id();
214 if (!arch_spin_trylock(&die_lock)) {
215 if (cpu == die_owner)
216 /* nested oops. should stop eventually */;
217 else
218 arch_spin_lock(&die_lock);
219 }
220 die_nest_count++;
221 die_owner = cpu;
222 console_verbose();
223 bust_spinlocks(1);
224 return flags;
225}
226EXPORT_SYMBOL_GPL(oops_begin);
227
228void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
229{
230 if (regs && kexec_should_crash(current))
231 crash_kexec(regs);
232
233 bust_spinlocks(0);
234 die_owner = -1;
235 add_taint(TAINT_DIE);
236 die_nest_count--;
237 if (!die_nest_count)
238 /* Nest count reaches zero, release the lock. */
239 arch_spin_unlock(&die_lock);
240 raw_local_irq_restore(flags);
241 oops_exit();
242
243 if (!signr)
244 return;
245 if (in_interrupt())
246 panic("Fatal exception in interrupt");
247 if (panic_on_oops)
248 panic("Fatal exception");
249 do_exit(signr);
250}
251
252int __kprobes __die(const char *str, struct pt_regs *regs, long err)
253{
254#ifdef CONFIG_X86_32
255 unsigned short ss;
256 unsigned long sp;
257#endif
258 printk(KERN_DEFAULT
259 "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
260#ifdef CONFIG_PREEMPT
261 printk("PREEMPT ");
262#endif
263#ifdef CONFIG_SMP
264 printk("SMP ");
265#endif
266#ifdef CONFIG_DEBUG_PAGEALLOC
267 printk("DEBUG_PAGEALLOC");
268#endif
269 printk("\n");
270 if (notify_die(DIE_OOPS, str, regs, err,
271 current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
272 return 1;
273
274 show_regs(regs);
275#ifdef CONFIG_X86_32
276 if (user_mode_vm(regs)) {
277 sp = regs->sp;
278 ss = regs->ss & 0xffff;
279 } else {
280 sp = kernel_stack_pointer(regs);
281 savesegment(ss, ss);
282 }
283 printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
284 print_symbol("%s", regs->ip);
285 printk(" SS:ESP %04x:%08lx\n", ss, sp);
286#else
287 /* Executive summary in case the oops scrolled away */
288 printk(KERN_ALERT "RIP ");
289 printk_address(regs->ip, 1);
290 printk(" RSP <%016lx>\n", regs->sp);
291#endif
292 return 0;
293}
294
295/*
296 * This is gone through when something in the kernel has done something bad
297 * and is about to be terminated:
298 */
299void die(const char *str, struct pt_regs *regs, long err)
300{
301 unsigned long flags = oops_begin();
302 int sig = SIGSEGV;
303
304 if (!user_mode_vm(regs))
305 report_bug(regs->ip, regs);
306
307 if (__die(str, regs, err))
308 sig = 0;
309 oops_end(flags, regs, sig);
310}
311
312static int __init kstack_setup(char *s)
313{
314 ssize_t ret;
315 unsigned long val;
316
317 if (!s)
318 return -EINVAL;
319
320 ret = kstrtoul(s, 0, &val);
321 if (ret)
322 return ret;
323 kstack_depth_to_print = val;
324 return 0;
325}
326early_param("kstack", kstack_setup);
327
328static int __init code_bytes_setup(char *s)
329{
330 ssize_t ret;
331 unsigned long val;
332
333 if (!s)
334 return -EINVAL;
335
336 ret = kstrtoul(s, 0, &val);
337 if (ret)
338 return ret;
339
340 code_bytes = val;
341 if (code_bytes > 8192)
342 code_bytes = 8192;
343
344 return 1;
345}
346__setup("code_bytes=", code_bytes_setup);
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/ftrace.h>
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>
20#include <asm/unwind.h>
21
22int panic_on_unrecovered_nmi;
23int panic_on_io_nmi;
24unsigned int code_bytes = 64;
25static int die_counter;
26
27bool 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
44static void printk_stack_address(unsigned long address, int reliable,
45 char *log_lvl)
46{
47 touch_nmi_watchdog();
48 printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
49}
50
51void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
52 unsigned long *stack, char *log_lvl)
53{
54 struct unwind_state state;
55 struct stack_info stack_info = {0};
56 unsigned long visit_mask = 0;
57 int graph_idx = 0;
58
59 printk("%sCall Trace:\n", log_lvl);
60
61 unwind_start(&state, task, regs, stack);
62 stack = stack ? : get_stack_pointer(task, regs);
63
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 */
78 for (regs = NULL; stack; stack = stack_info.next_sp) {
79 const char *stack_name;
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
91 stack_name = stack_type_name(stack_info.type);
92 if (stack_name)
93 printk("%s <%s>\n", log_lvl, stack_name);
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;
108 unsigned long addr = READ_ONCE_NOCHECK(*stack);
109 unsigned long *ret_addr_p =
110 unwind_get_return_address_ptr(&state);
111
112 if (!__kernel_text_address(addr))
113 continue;
114
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
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);
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);
156 }
157
158 if (stack_name)
159 printk("%s </%s>\n", log_lvl, stack_name);
160 }
161}
162
163void show_stack(struct task_struct *task, unsigned long *sp)
164{
165 task = task ? : current;
166
167 /*
168 * Stack frames below this one aren't interesting. Don't show them
169 * if we're printing for %current.
170 */
171 if (!sp && task == current)
172 sp = get_stack_pointer(current, NULL);
173
174 show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT);
175}
176
177void show_stack_regs(struct pt_regs *regs)
178{
179 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
180}
181
182static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
183static int die_owner = -1;
184static unsigned int die_nest_count;
185
186unsigned long oops_begin(void)
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();
196 if (!arch_spin_trylock(&die_lock)) {
197 if (cpu == die_owner)
198 /* nested oops. should stop eventually */;
199 else
200 arch_spin_lock(&die_lock);
201 }
202 die_nest_count++;
203 die_owner = cpu;
204 console_verbose();
205 bust_spinlocks(1);
206 return flags;
207}
208EXPORT_SYMBOL_GPL(oops_begin);
209NOKPROBE_SYMBOL(oops_begin);
210
211void __noreturn rewind_stack_do_exit(int signr);
212
213void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
214{
215 if (regs && kexec_should_crash(current))
216 crash_kexec(regs);
217
218 bust_spinlocks(0);
219 die_owner = -1;
220 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
221 die_nest_count--;
222 if (!die_nest_count)
223 /* Nest count reaches zero, release the lock. */
224 arch_spin_unlock(&die_lock);
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");
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);
241}
242NOKPROBE_SYMBOL(oops_end);
243
244int __die(const char *str, struct pt_regs *regs, long err)
245{
246#ifdef CONFIG_X86_32
247 unsigned short ss;
248 unsigned long sp;
249#endif
250 printk(KERN_DEFAULT
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
257 if (notify_die(DIE_OOPS, str, regs, err,
258 current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
259 return 1;
260
261 print_modules();
262 show_regs(regs);
263#ifdef CONFIG_X86_32
264 if (user_mode(regs)) {
265 sp = regs->sp;
266 ss = regs->ss & 0xffff;
267 } else {
268 sp = kernel_stack_pointer(regs);
269 savesegment(ss, ss);
270 }
271 printk(KERN_EMERG "EIP: %pS SS:ESP: %04x:%08lx\n",
272 (void *)regs->ip, ss, sp);
273#else
274 /* Executive summary in case the oops scrolled away */
275 printk(KERN_ALERT "RIP: %pS RSP: %016lx\n", (void *)regs->ip, regs->sp);
276#endif
277 return 0;
278}
279NOKPROBE_SYMBOL(__die);
280
281/*
282 * This is gone through when something in the kernel has done something bad
283 * and is about to be terminated:
284 */
285void die(const char *str, struct pt_regs *regs, long err)
286{
287 unsigned long flags = oops_begin();
288 int sig = SIGSEGV;
289
290 if (!user_mode(regs))
291 report_bug(regs->ip, regs);
292
293 if (__die(str, regs, err))
294 sig = 0;
295 oops_end(flags, regs, sig);
296}
297
298static int __init code_bytes_setup(char *s)
299{
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;
311 if (code_bytes > 8192)
312 code_bytes = 8192;
313
314 return 1;
315}
316__setup("code_bytes=", code_bytes_setup);