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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 
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)28 static void printk_stack_address(unsigned long address, int reliable)
29 {
30 	pr_cont(" [<%p>] %s%pB\n",
31 		(void *)address, reliable ? "" : "? ", (void *)address);
32 }
33 
printk_address(unsigned long address)34 void printk_address(unsigned long address)
35 {
36 	pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
37 }
38 
39 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
40 static void
print_ftrace_graph_addr(unsigned long addr,void * data,const struct stacktrace_ops * ops,struct thread_info * tinfo,int * graph)41 print_ftrace_graph_addr(unsigned long addr, void *data,
42 			const struct stacktrace_ops *ops,
43 			struct thread_info *tinfo, int *graph)
44 {
45 	struct task_struct *task;
46 	unsigned long ret_addr;
47 	int index;
48 
49 	if (addr != (unsigned long)return_to_handler)
50 		return;
51 
52 	task = tinfo->task;
53 	index = task->curr_ret_stack;
54 
55 	if (!task->ret_stack || index < *graph)
56 		return;
57 
58 	index -= *graph;
59 	ret_addr = task->ret_stack[index].ret;
60 
61 	ops->address(data, ret_addr, 1);
62 
63 	(*graph)++;
64 }
65 #else
66 static inline void
print_ftrace_graph_addr(unsigned long addr,void * data,const struct stacktrace_ops * ops,struct thread_info * tinfo,int * graph)67 print_ftrace_graph_addr(unsigned long addr, void *data,
68 			const struct stacktrace_ops *ops,
69 			struct thread_info *tinfo, int *graph)
70 { }
71 #endif
72 
73 /*
74  * x86-64 can have up to three kernel stacks:
75  * process stack
76  * interrupt stack
77  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
78  */
79 
valid_stack_ptr(struct thread_info * tinfo,void * p,unsigned int size,void * end)80 static inline int valid_stack_ptr(struct thread_info *tinfo,
81 			void *p, unsigned int size, void *end)
82 {
83 	void *t = tinfo;
84 	if (end) {
85 		if (p < end && p >= (end-THREAD_SIZE))
86 			return 1;
87 		else
88 			return 0;
89 	}
90 	return p > t && p < t + THREAD_SIZE - size;
91 }
92 
93 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)94 print_context_stack(struct thread_info *tinfo,
95 		unsigned long *stack, unsigned long bp,
96 		const struct stacktrace_ops *ops, void *data,
97 		unsigned long *end, int *graph)
98 {
99 	struct stack_frame *frame = (struct stack_frame *)bp;
100 
101 	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
102 		unsigned long addr;
103 
104 		addr = *stack;
105 		if (__kernel_text_address(addr)) {
106 			if ((unsigned long) stack == bp + sizeof(long)) {
107 				ops->address(data, addr, 1);
108 				frame = frame->next_frame;
109 				bp = (unsigned long) frame;
110 			} else {
111 				ops->address(data, addr, 0);
112 			}
113 			print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
114 		}
115 		stack++;
116 	}
117 	return bp;
118 }
119 EXPORT_SYMBOL_GPL(print_context_stack);
120 
121 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)122 print_context_stack_bp(struct thread_info *tinfo,
123 		       unsigned long *stack, unsigned long bp,
124 		       const struct stacktrace_ops *ops, void *data,
125 		       unsigned long *end, int *graph)
126 {
127 	struct stack_frame *frame = (struct stack_frame *)bp;
128 	unsigned long *ret_addr = &frame->return_address;
129 
130 	while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
131 		unsigned long addr = *ret_addr;
132 
133 		if (!__kernel_text_address(addr))
134 			break;
135 
136 		ops->address(data, addr, 1);
137 		frame = frame->next_frame;
138 		ret_addr = &frame->return_address;
139 		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
140 	}
141 
142 	return (unsigned long)frame;
143 }
144 EXPORT_SYMBOL_GPL(print_context_stack_bp);
145 
print_trace_stack(void * data,char * name)146 static int print_trace_stack(void *data, char *name)
147 {
148 	printk("%s <%s> ", (char *)data, name);
149 	return 0;
150 }
151 
152 /*
153  * Print one address/symbol entries per line.
154  */
print_trace_address(void * data,unsigned long addr,int reliable)155 static void print_trace_address(void *data, unsigned long addr, int reliable)
156 {
157 	touch_nmi_watchdog();
158 	printk(data);
159 	printk_stack_address(addr, reliable);
160 }
161 
162 static const struct stacktrace_ops print_trace_ops = {
163 	.stack			= print_trace_stack,
164 	.address		= print_trace_address,
165 	.walk_stack		= print_context_stack,
166 };
167 
168 void
show_trace_log_lvl(struct task_struct * task,struct pt_regs * regs,unsigned long * stack,unsigned long bp,char * log_lvl)169 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
170 		unsigned long *stack, unsigned long bp, char *log_lvl)
171 {
172 	printk("%sCall Trace:\n", log_lvl);
173 	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
174 }
175 
show_trace(struct task_struct * task,struct pt_regs * regs,unsigned long * stack,unsigned long bp)176 void show_trace(struct task_struct *task, struct pt_regs *regs,
177 		unsigned long *stack, unsigned long bp)
178 {
179 	show_trace_log_lvl(task, regs, stack, bp, "");
180 }
181 
show_stack(struct task_struct * task,unsigned long * sp)182 void show_stack(struct task_struct *task, unsigned long *sp)
183 {
184 	unsigned long bp = 0;
185 	unsigned long stack;
186 
187 	/*
188 	 * Stack frames below this one aren't interesting.  Don't show them
189 	 * if we're printing for %current.
190 	 */
191 	if (!sp && (!task || task == current)) {
192 		sp = &stack;
193 		bp = stack_frame(current, NULL);
194 	}
195 
196 	show_stack_log_lvl(task, NULL, sp, bp, "");
197 }
198 
199 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
200 static int die_owner = -1;
201 static unsigned int die_nest_count;
202 
oops_begin(void)203 unsigned long oops_begin(void)
204 {
205 	int cpu;
206 	unsigned long flags;
207 
208 	oops_enter();
209 
210 	/* racy, but better than risking deadlock. */
211 	raw_local_irq_save(flags);
212 	cpu = smp_processor_id();
213 	if (!arch_spin_trylock(&die_lock)) {
214 		if (cpu == die_owner)
215 			/* nested oops. should stop eventually */;
216 		else
217 			arch_spin_lock(&die_lock);
218 	}
219 	die_nest_count++;
220 	die_owner = cpu;
221 	console_verbose();
222 	bust_spinlocks(1);
223 	return flags;
224 }
225 EXPORT_SYMBOL_GPL(oops_begin);
226 NOKPROBE_SYMBOL(oops_begin);
227 
oops_end(unsigned long flags,struct pt_regs * regs,int signr)228 void 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, LOCKDEP_NOW_UNRELIABLE);
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 NOKPROBE_SYMBOL(oops_end);
252 
__die(const char * str,struct pt_regs * regs,long err)253 int __die(const char *str, struct pt_regs *regs, long err)
254 {
255 #ifdef CONFIG_X86_32
256 	unsigned short ss;
257 	unsigned long sp;
258 #endif
259 	printk(KERN_DEFAULT
260 	       "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
261 #ifdef CONFIG_PREEMPT
262 	printk("PREEMPT ");
263 #endif
264 #ifdef CONFIG_SMP
265 	printk("SMP ");
266 #endif
267 #ifdef CONFIG_DEBUG_PAGEALLOC
268 	printk("DEBUG_PAGEALLOC");
269 #endif
270 	printk("\n");
271 	if (notify_die(DIE_OOPS, str, regs, err,
272 			current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
273 		return 1;
274 
275 	print_modules();
276 	show_regs(regs);
277 #ifdef CONFIG_X86_32
278 	if (user_mode_vm(regs)) {
279 		sp = regs->sp;
280 		ss = regs->ss & 0xffff;
281 	} else {
282 		sp = kernel_stack_pointer(regs);
283 		savesegment(ss, ss);
284 	}
285 	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
286 	print_symbol("%s", regs->ip);
287 	printk(" SS:ESP %04x:%08lx\n", ss, sp);
288 #else
289 	/* Executive summary in case the oops scrolled away */
290 	printk(KERN_ALERT "RIP ");
291 	printk_address(regs->ip);
292 	printk(" RSP <%016lx>\n", regs->sp);
293 #endif
294 	return 0;
295 }
296 NOKPROBE_SYMBOL(__die);
297 
298 /*
299  * This is gone through when something in the kernel has done something bad
300  * and is about to be terminated:
301  */
die(const char * str,struct pt_regs * regs,long err)302 void die(const char *str, struct pt_regs *regs, long err)
303 {
304 	unsigned long flags = oops_begin();
305 	int sig = SIGSEGV;
306 
307 	if (!user_mode_vm(regs))
308 		report_bug(regs->ip, regs);
309 
310 	if (__die(str, regs, err))
311 		sig = 0;
312 	oops_end(flags, regs, sig);
313 }
314 
kstack_setup(char * s)315 static int __init kstack_setup(char *s)
316 {
317 	ssize_t ret;
318 	unsigned long val;
319 
320 	if (!s)
321 		return -EINVAL;
322 
323 	ret = kstrtoul(s, 0, &val);
324 	if (ret)
325 		return ret;
326 	kstack_depth_to_print = val;
327 	return 0;
328 }
329 early_param("kstack", kstack_setup);
330 
code_bytes_setup(char * s)331 static int __init code_bytes_setup(char *s)
332 {
333 	ssize_t ret;
334 	unsigned long val;
335 
336 	if (!s)
337 		return -EINVAL;
338 
339 	ret = kstrtoul(s, 0, &val);
340 	if (ret)
341 		return ret;
342 
343 	code_bytes = val;
344 	if (code_bytes > 8192)
345 		code_bytes = 8192;
346 
347 	return 1;
348 }
349 __setup("code_bytes=", code_bytes_setup);
350