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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/stacktrace.h>
22#include <asm/unwind.h>
23
24int panic_on_unrecovered_nmi;
25int panic_on_io_nmi;
26unsigned int code_bytes = 64;
27static int die_counter;
28
29bool in_task_stack(unsigned long *stack, struct task_struct *task,
30 struct stack_info *info)
31{
32 unsigned long *begin = task_stack_page(task);
33 unsigned long *end = task_stack_page(task) + THREAD_SIZE;
34
35 if (stack < begin || stack >= end)
36 return false;
37
38 info->type = STACK_TYPE_TASK;
39 info->begin = begin;
40 info->end = end;
41 info->next_sp = NULL;
42
43 return true;
44}
45
46static void printk_stack_address(unsigned long address, int reliable,
47 char *log_lvl)
48{
49 touch_nmi_watchdog();
50 printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
51}
52
53void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
54 unsigned long *stack, char *log_lvl)
55{
56 struct unwind_state state;
57 struct stack_info stack_info = {0};
58 unsigned long visit_mask = 0;
59 int graph_idx = 0;
60
61 printk("%sCall Trace:\n", log_lvl);
62
63 unwind_start(&state, task, regs, stack);
64 stack = stack ? : get_stack_pointer(task, regs);
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75
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77
78
79
80 for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
81 const char *stack_name;
82
83
84
85
86
87 if (task_stack_page(task) - (void *)stack < PAGE_SIZE)
88 stack = task_stack_page(task);
89
90 if (get_stack_info(stack, task, &stack_info, &visit_mask))
91 break;
92
93 stack_name = stack_type_name(stack_info.type);
94 if (stack_name)
95 printk("%s <%s>\n", log_lvl, stack_name);
96
97
98
99
100
101
102
103
104
105
106
107 for (; stack < stack_info.end; stack++) {
108 unsigned long real_addr;
109 int reliable = 0;
110 unsigned long addr = READ_ONCE_NOCHECK(*stack);
111 unsigned long *ret_addr_p =
112 unwind_get_return_address_ptr(&state);
113
114 if (!__kernel_text_address(addr))
115 continue;
116
117
118
119
120
121 if (regs && stack == ®s->ip) {
122 unwind_next_frame(&state);
123 continue;
124 }
125
126 if (stack == ret_addr_p)
127 reliable = 1;
128
129
130
131
132
133
134
135
136
137
138 real_addr = ftrace_graph_ret_addr(task, &graph_idx,
139 addr, stack);
140 if (real_addr != addr)
141 printk_stack_address(addr, 0, log_lvl);
142 printk_stack_address(real_addr, reliable, log_lvl);
143
144 if (!reliable)
145 continue;
146
147
148
149
150
151
152 unwind_next_frame(&state);
153
154
155 regs = unwind_get_entry_regs(&state);
156 if (regs)
157 __show_regs(regs, 0);
158 }
159
160 if (stack_name)
161 printk("%s </%s>\n", log_lvl, stack_name);
162 }
163}
164
165void show_stack(struct task_struct *task, unsigned long *sp)
166{
167 task = task ? : current;
168
169
170
171
172
173 if (!sp && task == current)
174 sp = get_stack_pointer(current, NULL);
175
176 show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT);
177}
178
179void show_stack_regs(struct pt_regs *regs)
180{
181 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
182}
183
184static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
185static int die_owner = -1;
186static unsigned int die_nest_count;
187
188unsigned long oops_begin(void)
189{
190 int cpu;
191 unsigned long flags;
192
193 oops_enter();
194
195
196 raw_local_irq_save(flags);
197 cpu = smp_processor_id();
198 if (!arch_spin_trylock(&die_lock)) {
199 if (cpu == die_owner)
200 ;
201 else
202 arch_spin_lock(&die_lock);
203 }
204 die_nest_count++;
205 die_owner = cpu;
206 console_verbose();
207 bust_spinlocks(1);
208 return flags;
209}
210EXPORT_SYMBOL_GPL(oops_begin);
211NOKPROBE_SYMBOL(oops_begin);
212
213void __noreturn rewind_stack_do_exit(int signr);
214
215void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
216{
217 if (regs && kexec_should_crash(current))
218 crash_kexec(regs);
219
220 bust_spinlocks(0);
221 die_owner = -1;
222 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
223 die_nest_count--;
224 if (!die_nest_count)
225
226 arch_spin_unlock(&die_lock);
227 raw_local_irq_restore(flags);
228 oops_exit();
229
230 if (!signr)
231 return;
232 if (in_interrupt())
233 panic("Fatal exception in interrupt");
234 if (panic_on_oops)
235 panic("Fatal exception");
236
237
238
239
240
241
242 rewind_stack_do_exit(signr);
243}
244NOKPROBE_SYMBOL(oops_end);
245
246int __die(const char *str, struct pt_regs *regs, long err)
247{
248#ifdef CONFIG_X86_32
249 unsigned short ss;
250 unsigned long sp;
251#endif
252 printk(KERN_DEFAULT
253 "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
254 IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
255 IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
256 debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
257 IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "");
258
259 if (notify_die(DIE_OOPS, str, regs, err,
260 current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
261 return 1;
262
263 print_modules();
264 show_regs(regs);
265#ifdef CONFIG_X86_32
266 if (user_mode(regs)) {
267 sp = regs->sp;
268 ss = regs->ss & 0xffff;
269 } else {
270 sp = kernel_stack_pointer(regs);
271 savesegment(ss, ss);
272 }
273 printk(KERN_EMERG "EIP: %pS SS:ESP: %04x:%08lx\n",
274 (void *)regs->ip, ss, sp);
275#else
276
277 printk(KERN_ALERT "RIP: %pS RSP: %016lx\n", (void *)regs->ip, regs->sp);
278#endif
279 return 0;
280}
281NOKPROBE_SYMBOL(__die);
282
283
284
285
286
287void die(const char *str, struct pt_regs *regs, long err)
288{
289 unsigned long flags = oops_begin();
290 int sig = SIGSEGV;
291
292 if (__die(str, regs, err))
293 sig = 0;
294 oops_end(flags, regs, sig);
295}
296
297static int __init code_bytes_setup(char *s)
298{
299 ssize_t ret;
300 unsigned long val;
301
302 if (!s)
303 return -EINVAL;
304
305 ret = kstrtoul(s, 0, &val);
306 if (ret)
307 return ret;
308
309 code_bytes = val;
310 if (code_bytes > 8192)
311 code_bytes = 8192;
312
313 return 1;
314}
315__setup("code_bytes=", code_bytes_setup);
316