xref: /openbmc/linux/arch/x86/kernel/dumpstack.c (revision 4800cd83)
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 
28 void printk_address(unsigned long address, int reliable)
29 {
30 	printk(" [<%p>] %s%pS\n", (void *) address,
31 			reliable ? "" : "? ", (void *) address);
32 }
33 
34 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
35 static void
36 print_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 = tinfo->task;
41 	unsigned long ret_addr;
42 	int index = task->curr_ret_stack;
43 
44 	if (addr != (unsigned long)return_to_handler)
45 		return;
46 
47 	if (!task->ret_stack || index < *graph)
48 		return;
49 
50 	index -= *graph;
51 	ret_addr = task->ret_stack[index].ret;
52 
53 	ops->address(data, ret_addr, 1);
54 
55 	(*graph)++;
56 }
57 #else
58 static inline void
59 print_ftrace_graph_addr(unsigned long addr, void *data,
60 			const struct stacktrace_ops *ops,
61 			struct thread_info *tinfo, int *graph)
62 { }
63 #endif
64 
65 /*
66  * x86-64 can have up to three kernel stacks:
67  * process stack
68  * interrupt stack
69  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
70  */
71 
72 static inline int valid_stack_ptr(struct thread_info *tinfo,
73 			void *p, unsigned int size, void *end)
74 {
75 	void *t = tinfo;
76 	if (end) {
77 		if (p < end && p >= (end-THREAD_SIZE))
78 			return 1;
79 		else
80 			return 0;
81 	}
82 	return p > t && p < t + THREAD_SIZE - size;
83 }
84 
85 unsigned long
86 print_context_stack(struct thread_info *tinfo,
87 		unsigned long *stack, unsigned long bp,
88 		const struct stacktrace_ops *ops, void *data,
89 		unsigned long *end, int *graph)
90 {
91 	struct stack_frame *frame = (struct stack_frame *)bp;
92 
93 	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
94 		unsigned long addr;
95 
96 		addr = *stack;
97 		if (__kernel_text_address(addr)) {
98 			if ((unsigned long) stack == bp + sizeof(long)) {
99 				ops->address(data, addr, 1);
100 				frame = frame->next_frame;
101 				bp = (unsigned long) frame;
102 			} else {
103 				ops->address(data, addr, 0);
104 			}
105 			print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
106 		}
107 		stack++;
108 	}
109 	return bp;
110 }
111 EXPORT_SYMBOL_GPL(print_context_stack);
112 
113 unsigned long
114 print_context_stack_bp(struct thread_info *tinfo,
115 		       unsigned long *stack, unsigned long bp,
116 		       const struct stacktrace_ops *ops, void *data,
117 		       unsigned long *end, int *graph)
118 {
119 	struct stack_frame *frame = (struct stack_frame *)bp;
120 	unsigned long *ret_addr = &frame->return_address;
121 
122 	while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
123 		unsigned long addr = *ret_addr;
124 
125 		if (!__kernel_text_address(addr))
126 			break;
127 
128 		ops->address(data, addr, 1);
129 		frame = frame->next_frame;
130 		ret_addr = &frame->return_address;
131 		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
132 	}
133 
134 	return (unsigned long)frame;
135 }
136 EXPORT_SYMBOL_GPL(print_context_stack_bp);
137 
138 
139 static void
140 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
141 {
142 	printk(data);
143 	print_symbol(msg, symbol);
144 	printk("\n");
145 }
146 
147 static void print_trace_warning(void *data, char *msg)
148 {
149 	printk("%s%s\n", (char *)data, msg);
150 }
151 
152 static int print_trace_stack(void *data, char *name)
153 {
154 	printk("%s <%s> ", (char *)data, name);
155 	return 0;
156 }
157 
158 /*
159  * Print one address/symbol entries per line.
160  */
161 static void print_trace_address(void *data, unsigned long addr, int reliable)
162 {
163 	touch_nmi_watchdog();
164 	printk(data);
165 	printk_address(addr, reliable);
166 }
167 
168 static const struct stacktrace_ops print_trace_ops = {
169 	.warning		= print_trace_warning,
170 	.warning_symbol		= print_trace_warning_symbol,
171 	.stack			= print_trace_stack,
172 	.address		= print_trace_address,
173 	.walk_stack		= print_context_stack,
174 };
175 
176 void
177 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
178 		unsigned long *stack, char *log_lvl)
179 {
180 	printk("%sCall Trace:\n", log_lvl);
181 	dump_trace(task, regs, stack, &print_trace_ops, log_lvl);
182 }
183 
184 void show_trace(struct task_struct *task, struct pt_regs *regs,
185 		unsigned long *stack)
186 {
187 	show_trace_log_lvl(task, regs, stack, "");
188 }
189 
190 void show_stack(struct task_struct *task, unsigned long *sp)
191 {
192 	show_stack_log_lvl(task, NULL, sp, "");
193 }
194 
195 /*
196  * The architecture-independent dump_stack generator
197  */
198 void dump_stack(void)
199 {
200 	unsigned long stack;
201 
202 	printk("Pid: %d, comm: %.20s %s %s %.*s\n",
203 		current->pid, current->comm, print_tainted(),
204 		init_utsname()->release,
205 		(int)strcspn(init_utsname()->version, " "),
206 		init_utsname()->version);
207 	show_trace(NULL, NULL, &stack);
208 }
209 EXPORT_SYMBOL(dump_stack);
210 
211 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
212 static int die_owner = -1;
213 static unsigned int die_nest_count;
214 
215 unsigned __kprobes long oops_begin(void)
216 {
217 	int cpu;
218 	unsigned long flags;
219 
220 	oops_enter();
221 
222 	/* racy, but better than risking deadlock. */
223 	raw_local_irq_save(flags);
224 	cpu = smp_processor_id();
225 	if (!arch_spin_trylock(&die_lock)) {
226 		if (cpu == die_owner)
227 			/* nested oops. should stop eventually */;
228 		else
229 			arch_spin_lock(&die_lock);
230 	}
231 	die_nest_count++;
232 	die_owner = cpu;
233 	console_verbose();
234 	bust_spinlocks(1);
235 	return flags;
236 }
237 EXPORT_SYMBOL_GPL(oops_begin);
238 
239 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
240 {
241 	if (regs && kexec_should_crash(current))
242 		crash_kexec(regs);
243 
244 	bust_spinlocks(0);
245 	die_owner = -1;
246 	add_taint(TAINT_DIE);
247 	die_nest_count--;
248 	if (!die_nest_count)
249 		/* Nest count reaches zero, release the lock. */
250 		arch_spin_unlock(&die_lock);
251 	raw_local_irq_restore(flags);
252 	oops_exit();
253 
254 	if (!signr)
255 		return;
256 	if (in_interrupt())
257 		panic("Fatal exception in interrupt");
258 	if (panic_on_oops)
259 		panic("Fatal exception");
260 	do_exit(signr);
261 }
262 
263 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
264 {
265 #ifdef CONFIG_X86_32
266 	unsigned short ss;
267 	unsigned long sp;
268 #endif
269 	printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
270 #ifdef CONFIG_PREEMPT
271 	printk("PREEMPT ");
272 #endif
273 #ifdef CONFIG_SMP
274 	printk("SMP ");
275 #endif
276 #ifdef CONFIG_DEBUG_PAGEALLOC
277 	printk("DEBUG_PAGEALLOC");
278 #endif
279 	printk("\n");
280 	sysfs_printk_last_file();
281 	if (notify_die(DIE_OOPS, str, regs, err,
282 			current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
283 		return 1;
284 
285 	show_registers(regs);
286 #ifdef CONFIG_X86_32
287 	if (user_mode_vm(regs)) {
288 		sp = regs->sp;
289 		ss = regs->ss & 0xffff;
290 	} else {
291 		sp = kernel_stack_pointer(regs);
292 		savesegment(ss, ss);
293 	}
294 	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
295 	print_symbol("%s", regs->ip);
296 	printk(" SS:ESP %04x:%08lx\n", ss, sp);
297 #else
298 	/* Executive summary in case the oops scrolled away */
299 	printk(KERN_ALERT "RIP ");
300 	printk_address(regs->ip, 1);
301 	printk(" RSP <%016lx>\n", regs->sp);
302 #endif
303 	return 0;
304 }
305 
306 /*
307  * This is gone through when something in the kernel has done something bad
308  * and is about to be terminated:
309  */
310 void die(const char *str, struct pt_regs *regs, long err)
311 {
312 	unsigned long flags = oops_begin();
313 	int sig = SIGSEGV;
314 
315 	if (!user_mode_vm(regs))
316 		report_bug(regs->ip, regs);
317 
318 	if (__die(str, regs, err))
319 		sig = 0;
320 	oops_end(flags, regs, sig);
321 }
322 
323 void notrace __kprobes
324 die_nmi(char *str, struct pt_regs *regs, int do_panic)
325 {
326 	unsigned long flags;
327 
328 	if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
329 		return;
330 
331 	/*
332 	 * We are in trouble anyway, lets at least try
333 	 * to get a message out.
334 	 */
335 	flags = oops_begin();
336 	printk(KERN_EMERG "%s", str);
337 	printk(" on CPU%d, ip %08lx, registers:\n",
338 		smp_processor_id(), regs->ip);
339 	show_registers(regs);
340 	oops_end(flags, regs, 0);
341 	if (do_panic || panic_on_oops)
342 		panic("Non maskable interrupt");
343 	nmi_exit();
344 	local_irq_enable();
345 	do_exit(SIGBUS);
346 }
347 
348 static int __init oops_setup(char *s)
349 {
350 	if (!s)
351 		return -EINVAL;
352 	if (!strcmp(s, "panic"))
353 		panic_on_oops = 1;
354 	return 0;
355 }
356 early_param("oops", oops_setup);
357 
358 static int __init kstack_setup(char *s)
359 {
360 	if (!s)
361 		return -EINVAL;
362 	kstack_depth_to_print = simple_strtoul(s, NULL, 0);
363 	return 0;
364 }
365 early_param("kstack", kstack_setup);
366 
367 static int __init code_bytes_setup(char *s)
368 {
369 	code_bytes = simple_strtoul(s, NULL, 0);
370 	if (code_bytes > 8192)
371 		code_bytes = 8192;
372 
373 	return 1;
374 }
375 __setup("code_bytes=", code_bytes_setup);
376