• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 
22 int panic_on_unrecovered_nmi;
23 int panic_on_io_nmi;
24 unsigned int code_bytes = 64;
25 int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
26 static int die_counter;
27 
printk_stack_address(unsigned long address,int reliable,void * data)28 static void printk_stack_address(unsigned long address, int reliable,
29 		void *data)
30 {
31 	printk("%s [<%p>] %s%pB\n",
32 		(char *)data, (void *)address, reliable ? "" : "? ",
33 		(void *)address);
34 }
35 
printk_address(unsigned long address)36 void printk_address(unsigned long address)
37 {
38 	pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
39 }
40 
41 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
42 static void
print_ftrace_graph_addr(unsigned long addr,void * data,const struct stacktrace_ops * ops,struct thread_info * tinfo,int * graph)43 print_ftrace_graph_addr(unsigned long addr, void *data,
44 			const struct stacktrace_ops *ops,
45 			struct thread_info *tinfo, int *graph)
46 {
47 	struct task_struct *task;
48 	unsigned long ret_addr;
49 	int index;
50 
51 	if (addr != (unsigned long)return_to_handler)
52 		return;
53 
54 	task = tinfo->task;
55 	index = task->curr_ret_stack;
56 
57 	if (!task->ret_stack || index < *graph)
58 		return;
59 
60 	index -= *graph;
61 	ret_addr = task->ret_stack[index].ret;
62 
63 	ops->address(data, ret_addr, 1);
64 
65 	(*graph)++;
66 }
67 #else
68 static inline void
print_ftrace_graph_addr(unsigned long addr,void * data,const struct stacktrace_ops * ops,struct thread_info * tinfo,int * graph)69 print_ftrace_graph_addr(unsigned long addr, void *data,
70 			const struct stacktrace_ops *ops,
71 			struct thread_info *tinfo, int *graph)
72 { }
73 #endif
74 
75 /*
76  * x86-64 can have up to three kernel stacks:
77  * process stack
78  * interrupt stack
79  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
80  */
81 
valid_stack_ptr(struct thread_info * tinfo,void * p,unsigned int size,void * end)82 static inline int valid_stack_ptr(struct thread_info *tinfo,
83 			void *p, unsigned int size, void *end)
84 {
85 	void *t = tinfo;
86 	if (end) {
87 		if (p < end && p >= (end-THREAD_SIZE))
88 			return 1;
89 		else
90 			return 0;
91 	}
92 	return p > t && p < t + THREAD_SIZE - size;
93 }
94 
95 unsigned long
print_context_stack(struct thread_info * tinfo,unsigned long * stack,unsigned long bp,const struct stacktrace_ops * ops,void * data,unsigned long * end,int * graph)96 print_context_stack(struct thread_info *tinfo,
97 		unsigned long *stack, unsigned long bp,
98 		const struct stacktrace_ops *ops, void *data,
99 		unsigned long *end, int *graph)
100 {
101 	struct stack_frame *frame = (struct stack_frame *)bp;
102 
103 	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
104 		unsigned long addr;
105 
106 		addr = *stack;
107 		if (__kernel_text_address(addr)) {
108 			if ((unsigned long) stack == bp + sizeof(long)) {
109 				ops->address(data, addr, 1);
110 				frame = frame->next_frame;
111 				bp = (unsigned long) frame;
112 			} else {
113 				ops->address(data, addr, 0);
114 			}
115 			print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
116 		}
117 		stack++;
118 	}
119 	return bp;
120 }
121 EXPORT_SYMBOL_GPL(print_context_stack);
122 
123 unsigned long
print_context_stack_bp(struct thread_info * tinfo,unsigned long * stack,unsigned long bp,const struct stacktrace_ops * ops,void * data,unsigned long * end,int * graph)124 print_context_stack_bp(struct thread_info *tinfo,
125 		       unsigned long *stack, unsigned long bp,
126 		       const struct stacktrace_ops *ops, void *data,
127 		       unsigned long *end, int *graph)
128 {
129 	struct stack_frame *frame = (struct stack_frame *)bp;
130 	unsigned long *ret_addr = &frame->return_address;
131 
132 	while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
133 		unsigned long addr = *ret_addr;
134 
135 		if (!__kernel_text_address(addr))
136 			break;
137 
138 		ops->address(data, addr, 1);
139 		frame = frame->next_frame;
140 		ret_addr = &frame->return_address;
141 		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
142 	}
143 
144 	return (unsigned long)frame;
145 }
146 EXPORT_SYMBOL_GPL(print_context_stack_bp);
147 
print_trace_stack(void * data,char * name)148 static int print_trace_stack(void *data, char *name)
149 {
150 	printk("%s <%s> ", (char *)data, name);
151 	return 0;
152 }
153 
154 /*
155  * Print one address/symbol entries per line.
156  */
print_trace_address(void * data,unsigned long addr,int reliable)157 static void print_trace_address(void *data, unsigned long addr, int reliable)
158 {
159 	touch_nmi_watchdog();
160 	printk_stack_address(addr, reliable, data);
161 }
162 
163 static const struct stacktrace_ops print_trace_ops = {
164 	.stack			= print_trace_stack,
165 	.address		= print_trace_address,
166 	.walk_stack		= print_context_stack,
167 };
168 
169 void
show_trace_log_lvl(struct task_struct * task,struct pt_regs * regs,unsigned long * stack,unsigned long bp,char * log_lvl)170 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
171 		unsigned long *stack, unsigned long bp, char *log_lvl)
172 {
173 	printk("%sCall Trace:\n", log_lvl);
174 	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
175 }
176 
show_trace(struct task_struct * task,struct pt_regs * regs,unsigned long * stack,unsigned long bp)177 void show_trace(struct task_struct *task, struct pt_regs *regs,
178 		unsigned long *stack, unsigned long bp)
179 {
180 	show_trace_log_lvl(task, regs, stack, bp, "");
181 }
182 
show_stack(struct task_struct * task,unsigned long * sp)183 void show_stack(struct task_struct *task, unsigned long *sp)
184 {
185 	unsigned long bp = 0;
186 	unsigned long stack;
187 
188 	/*
189 	 * Stack frames below this one aren't interesting.  Don't show them
190 	 * if we're printing for %current.
191 	 */
192 	if (!sp && (!task || task == current)) {
193 		sp = &stack;
194 		bp = stack_frame(current, NULL);
195 	}
196 
197 	show_stack_log_lvl(task, NULL, sp, bp, "");
198 }
199 
200 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
201 static int die_owner = -1;
202 static unsigned int die_nest_count;
203 
oops_begin(void)204 unsigned 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 }
226 EXPORT_SYMBOL_GPL(oops_begin);
227 NOKPROBE_SYMBOL(oops_begin);
228 
oops_end(unsigned long flags,struct pt_regs * regs,int signr)229 void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
230 {
231 	if (regs && kexec_should_crash(current))
232 		crash_kexec(regs);
233 
234 	bust_spinlocks(0);
235 	die_owner = -1;
236 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
237 	die_nest_count--;
238 	if (!die_nest_count)
239 		/* Nest count reaches zero, release the lock. */
240 		arch_spin_unlock(&die_lock);
241 	raw_local_irq_restore(flags);
242 	oops_exit();
243 
244 	if (!signr)
245 		return;
246 	if (in_interrupt())
247 		panic("Fatal exception in interrupt");
248 	if (panic_on_oops)
249 		panic("Fatal exception");
250 	do_exit(signr);
251 }
252 NOKPROBE_SYMBOL(oops_end);
253 
__die(const char * str,struct pt_regs * regs,long err)254 int __die(const char *str, struct pt_regs *regs, long err)
255 {
256 #ifdef CONFIG_X86_32
257 	unsigned short ss;
258 	unsigned long sp;
259 #endif
260 	printk(KERN_DEFAULT
261 	       "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
262 #ifdef CONFIG_PREEMPT
263 	printk("PREEMPT ");
264 #endif
265 #ifdef CONFIG_SMP
266 	printk("SMP ");
267 #endif
268 #ifdef CONFIG_DEBUG_PAGEALLOC
269 	printk("DEBUG_PAGEALLOC ");
270 #endif
271 #ifdef CONFIG_KASAN
272 	printk("KASAN");
273 #endif
274 	printk("\n");
275 	if (notify_die(DIE_OOPS, str, regs, err,
276 			current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
277 		return 1;
278 
279 	print_modules();
280 	show_regs(regs);
281 #ifdef CONFIG_X86_32
282 	if (user_mode(regs)) {
283 		sp = regs->sp;
284 		ss = regs->ss & 0xffff;
285 	} else {
286 		sp = kernel_stack_pointer(regs);
287 		savesegment(ss, ss);
288 	}
289 	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
290 	print_symbol("%s", regs->ip);
291 	printk(" SS:ESP %04x:%08lx\n", ss, sp);
292 #else
293 	/* Executive summary in case the oops scrolled away */
294 	printk(KERN_ALERT "RIP ");
295 	printk_address(regs->ip);
296 	printk(" RSP <%016lx>\n", regs->sp);
297 #endif
298 	return 0;
299 }
300 NOKPROBE_SYMBOL(__die);
301 
302 /*
303  * This is gone through when something in the kernel has done something bad
304  * and is about to be terminated:
305  */
die(const char * str,struct pt_regs * regs,long err)306 void die(const char *str, struct pt_regs *regs, long err)
307 {
308 	unsigned long flags = oops_begin();
309 	int sig = SIGSEGV;
310 
311 	if (!user_mode(regs))
312 		report_bug(regs->ip, regs);
313 
314 	if (__die(str, regs, err))
315 		sig = 0;
316 	oops_end(flags, regs, sig);
317 }
318 
kstack_setup(char * s)319 static int __init kstack_setup(char *s)
320 {
321 	ssize_t ret;
322 	unsigned long val;
323 
324 	if (!s)
325 		return -EINVAL;
326 
327 	ret = kstrtoul(s, 0, &val);
328 	if (ret)
329 		return ret;
330 	kstack_depth_to_print = val;
331 	return 0;
332 }
333 early_param("kstack", kstack_setup);
334 
code_bytes_setup(char * s)335 static int __init code_bytes_setup(char *s)
336 {
337 	ssize_t ret;
338 	unsigned long val;
339 
340 	if (!s)
341 		return -EINVAL;
342 
343 	ret = kstrtoul(s, 0, &val);
344 	if (ret)
345 		return ret;
346 
347 	code_bytes = val;
348 	if (code_bytes > 8192)
349 		code_bytes = 8192;
350 
351 	return 1;
352 }
353 __setup("code_bytes=", code_bytes_setup);
354