xref: /openbmc/linux/arch/x86/kernel/dumpstack.c (revision b6dcefde)
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 #include "dumpstack.h"
22 
23 int panic_on_unrecovered_nmi;
24 int panic_on_io_nmi;
25 unsigned int code_bytes = 64;
26 int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
27 static int die_counter;
28 
29 void printk_address(unsigned long address, int reliable)
30 {
31 	printk(" [<%p>] %s%pS\n", (void *) address,
32 			reliable ? "" : "? ", (void *) address);
33 }
34 
35 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
36 static void
37 print_ftrace_graph_addr(unsigned long addr, void *data,
38 			const struct stacktrace_ops *ops,
39 			struct thread_info *tinfo, int *graph)
40 {
41 	struct task_struct *task = tinfo->task;
42 	unsigned long ret_addr;
43 	int index = task->curr_ret_stack;
44 
45 	if (addr != (unsigned long)return_to_handler)
46 		return;
47 
48 	if (!task->ret_stack || index < *graph)
49 		return;
50 
51 	index -= *graph;
52 	ret_addr = task->ret_stack[index].ret;
53 
54 	ops->address(data, ret_addr, 1);
55 
56 	(*graph)++;
57 }
58 #else
59 static inline void
60 print_ftrace_graph_addr(unsigned long addr, void *data,
61 			const struct stacktrace_ops *ops,
62 			struct thread_info *tinfo, int *graph)
63 { }
64 #endif
65 
66 /*
67  * x86-64 can have up to three kernel stacks:
68  * process stack
69  * interrupt stack
70  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
71  */
72 
73 static inline int valid_stack_ptr(struct thread_info *tinfo,
74 			void *p, unsigned int size, void *end)
75 {
76 	void *t = tinfo;
77 	if (end) {
78 		if (p < end && p >= (end-THREAD_SIZE))
79 			return 1;
80 		else
81 			return 0;
82 	}
83 	return p > t && p < t + THREAD_SIZE - size;
84 }
85 
86 unsigned long
87 print_context_stack(struct thread_info *tinfo,
88 		unsigned long *stack, unsigned long bp,
89 		const struct stacktrace_ops *ops, void *data,
90 		unsigned long *end, int *graph)
91 {
92 	struct stack_frame *frame = (struct stack_frame *)bp;
93 
94 	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
95 		unsigned long addr;
96 
97 		addr = *stack;
98 		if (__kernel_text_address(addr)) {
99 			if ((unsigned long) stack == bp + sizeof(long)) {
100 				ops->address(data, addr, 1);
101 				frame = frame->next_frame;
102 				bp = (unsigned long) frame;
103 			} else {
104 				ops->address(data, addr, 0);
105 			}
106 			print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
107 		}
108 		stack++;
109 	}
110 	return bp;
111 }
112 EXPORT_SYMBOL_GPL(print_context_stack);
113 
114 unsigned long
115 print_context_stack_bp(struct thread_info *tinfo,
116 		       unsigned long *stack, unsigned long bp,
117 		       const struct stacktrace_ops *ops, void *data,
118 		       unsigned long *end, int *graph)
119 {
120 	struct stack_frame *frame = (struct stack_frame *)bp;
121 	unsigned long *ret_addr = &frame->return_address;
122 
123 	while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
124 		unsigned long addr = *ret_addr;
125 
126 		if (!__kernel_text_address(addr))
127 			break;
128 
129 		ops->address(data, addr, 1);
130 		frame = frame->next_frame;
131 		ret_addr = &frame->return_address;
132 		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
133 	}
134 
135 	return (unsigned long)frame;
136 }
137 EXPORT_SYMBOL_GPL(print_context_stack_bp);
138 
139 
140 static void
141 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
142 {
143 	printk(data);
144 	print_symbol(msg, symbol);
145 	printk("\n");
146 }
147 
148 static void print_trace_warning(void *data, char *msg)
149 {
150 	printk("%s%s\n", (char *)data, msg);
151 }
152 
153 static int print_trace_stack(void *data, char *name)
154 {
155 	printk("%s <%s> ", (char *)data, name);
156 	return 0;
157 }
158 
159 /*
160  * Print one address/symbol entries per line.
161  */
162 static void print_trace_address(void *data, unsigned long addr, int reliable)
163 {
164 	touch_nmi_watchdog();
165 	printk(data);
166 	printk_address(addr, reliable);
167 }
168 
169 static const struct stacktrace_ops print_trace_ops = {
170 	.warning		= print_trace_warning,
171 	.warning_symbol		= print_trace_warning_symbol,
172 	.stack			= print_trace_stack,
173 	.address		= print_trace_address,
174 	.walk_stack		= print_context_stack,
175 };
176 
177 void
178 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
179 		unsigned long *stack, unsigned long bp, char *log_lvl)
180 {
181 	printk("%sCall Trace:\n", log_lvl);
182 	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
183 }
184 
185 void show_trace(struct task_struct *task, struct pt_regs *regs,
186 		unsigned long *stack, unsigned long bp)
187 {
188 	show_trace_log_lvl(task, regs, stack, bp, "");
189 }
190 
191 void show_stack(struct task_struct *task, unsigned long *sp)
192 {
193 	show_stack_log_lvl(task, NULL, sp, 0, "");
194 }
195 
196 /*
197  * The architecture-independent dump_stack generator
198  */
199 void dump_stack(void)
200 {
201 	unsigned long bp = 0;
202 	unsigned long stack;
203 
204 #ifdef CONFIG_FRAME_POINTER
205 	if (!bp)
206 		get_bp(bp);
207 #endif
208 
209 	printk("Pid: %d, comm: %.20s %s %s %.*s\n",
210 		current->pid, current->comm, print_tainted(),
211 		init_utsname()->release,
212 		(int)strcspn(init_utsname()->version, " "),
213 		init_utsname()->version);
214 	show_trace(NULL, NULL, &stack, bp);
215 }
216 EXPORT_SYMBOL(dump_stack);
217 
218 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
219 static int die_owner = -1;
220 static unsigned int die_nest_count;
221 
222 unsigned __kprobes long oops_begin(void)
223 {
224 	int cpu;
225 	unsigned long flags;
226 
227 	/* notify the hw-branch tracer so it may disable tracing and
228 	   add the last trace to the trace buffer -
229 	   the earlier this happens, the more useful the trace. */
230 	trace_hw_branch_oops();
231 
232 	oops_enter();
233 
234 	/* racy, but better than risking deadlock. */
235 	raw_local_irq_save(flags);
236 	cpu = smp_processor_id();
237 	if (!arch_spin_trylock(&die_lock)) {
238 		if (cpu == die_owner)
239 			/* nested oops. should stop eventually */;
240 		else
241 			arch_spin_lock(&die_lock);
242 	}
243 	die_nest_count++;
244 	die_owner = cpu;
245 	console_verbose();
246 	bust_spinlocks(1);
247 	return flags;
248 }
249 
250 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
251 {
252 	if (regs && kexec_should_crash(current))
253 		crash_kexec(regs);
254 
255 	bust_spinlocks(0);
256 	die_owner = -1;
257 	add_taint(TAINT_DIE);
258 	die_nest_count--;
259 	if (!die_nest_count)
260 		/* Nest count reaches zero, release the lock. */
261 		arch_spin_unlock(&die_lock);
262 	raw_local_irq_restore(flags);
263 	oops_exit();
264 
265 	if (!signr)
266 		return;
267 	if (in_interrupt())
268 		panic("Fatal exception in interrupt");
269 	if (panic_on_oops)
270 		panic("Fatal exception");
271 	do_exit(signr);
272 }
273 
274 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
275 {
276 #ifdef CONFIG_X86_32
277 	unsigned short ss;
278 	unsigned long sp;
279 #endif
280 	printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
281 #ifdef CONFIG_PREEMPT
282 	printk("PREEMPT ");
283 #endif
284 #ifdef CONFIG_SMP
285 	printk("SMP ");
286 #endif
287 #ifdef CONFIG_DEBUG_PAGEALLOC
288 	printk("DEBUG_PAGEALLOC");
289 #endif
290 	printk("\n");
291 	sysfs_printk_last_file();
292 	if (notify_die(DIE_OOPS, str, regs, err,
293 			current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
294 		return 1;
295 
296 	show_registers(regs);
297 #ifdef CONFIG_X86_32
298 	if (user_mode_vm(regs)) {
299 		sp = regs->sp;
300 		ss = regs->ss & 0xffff;
301 	} else {
302 		sp = kernel_stack_pointer(regs);
303 		savesegment(ss, ss);
304 	}
305 	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
306 	print_symbol("%s", regs->ip);
307 	printk(" SS:ESP %04x:%08lx\n", ss, sp);
308 #else
309 	/* Executive summary in case the oops scrolled away */
310 	printk(KERN_ALERT "RIP ");
311 	printk_address(regs->ip, 1);
312 	printk(" RSP <%016lx>\n", regs->sp);
313 #endif
314 	return 0;
315 }
316 
317 /*
318  * This is gone through when something in the kernel has done something bad
319  * and is about to be terminated:
320  */
321 void die(const char *str, struct pt_regs *regs, long err)
322 {
323 	unsigned long flags = oops_begin();
324 	int sig = SIGSEGV;
325 
326 	if (!user_mode_vm(regs))
327 		report_bug(regs->ip, regs);
328 
329 	if (__die(str, regs, err))
330 		sig = 0;
331 	oops_end(flags, regs, sig);
332 }
333 
334 void notrace __kprobes
335 die_nmi(char *str, struct pt_regs *regs, int do_panic)
336 {
337 	unsigned long flags;
338 
339 	if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
340 		return;
341 
342 	/*
343 	 * We are in trouble anyway, lets at least try
344 	 * to get a message out.
345 	 */
346 	flags = oops_begin();
347 	printk(KERN_EMERG "%s", str);
348 	printk(" on CPU%d, ip %08lx, registers:\n",
349 		smp_processor_id(), regs->ip);
350 	show_registers(regs);
351 	oops_end(flags, regs, 0);
352 	if (do_panic || panic_on_oops)
353 		panic("Non maskable interrupt");
354 	nmi_exit();
355 	local_irq_enable();
356 	do_exit(SIGBUS);
357 }
358 
359 static int __init oops_setup(char *s)
360 {
361 	if (!s)
362 		return -EINVAL;
363 	if (!strcmp(s, "panic"))
364 		panic_on_oops = 1;
365 	return 0;
366 }
367 early_param("oops", oops_setup);
368 
369 static int __init kstack_setup(char *s)
370 {
371 	if (!s)
372 		return -EINVAL;
373 	kstack_depth_to_print = simple_strtoul(s, NULL, 0);
374 	return 0;
375 }
376 early_param("kstack", kstack_setup);
377 
378 static int __init code_bytes_setup(char *s)
379 {
380 	code_bytes = simple_strtoul(s, NULL, 0);
381 	if (code_bytes > 8192)
382 		code_bytes = 8192;
383 
384 	return 1;
385 }
386 __setup("code_bytes=", code_bytes_setup);
387