dumpstack_64.c revision 161827903bdc124655f4cd976b9f0a5ac6ebf21c 
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/kexec.h>
14#include <linux/bug.h>
15#include <linux/nmi.h>
16
17#include <asm/stacktrace.h>
18
19int panic_on_unrecovered_nmi;
20int kstack_depth_to_print = 12;
21static unsigned int code_bytes = 64;
22static int die_counter;
23
24void printk_address(unsigned long address, int reliable)
25{
26	printk(" [<%p>] %s%pS\n", (void *) address,
27			reliable ? "" : "? ", (void *) address);
28}
29
30static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
31					unsigned *usedp, char **idp)
32{
33	static char ids[][8] = {
34		[DEBUG_STACK - 1] = "#DB",
35		[NMI_STACK - 1] = "NMI",
36		[DOUBLEFAULT_STACK - 1] = "#DF",
37		[STACKFAULT_STACK - 1] = "#SS",
38		[MCE_STACK - 1] = "#MC",
39#if DEBUG_STKSZ > EXCEPTION_STKSZ
40		[N_EXCEPTION_STACKS ...
41			N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]"
42#endif
43	};
44	unsigned k;
45
46	/*
47	 * Iterate over all exception stacks, and figure out whether
48	 * 'stack' is in one of them:
49	 */
50	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
51		unsigned long end = per_cpu(orig_ist, cpu).ist[k];
52		/*
53		 * Is 'stack' above this exception frame's end?
54		 * If yes then skip to the next frame.
55		 */
56		if (stack >= end)
57			continue;
58		/*
59		 * Is 'stack' above this exception frame's start address?
60		 * If yes then we found the right frame.
61		 */
62		if (stack >= end - EXCEPTION_STKSZ) {
63			/*
64			 * Make sure we only iterate through an exception
65			 * stack once. If it comes up for the second time
66			 * then there's something wrong going on - just
67			 * break out and return NULL:
68			 */
69			if (*usedp & (1U << k))
70				break;
71			*usedp |= 1U << k;
72			*idp = ids[k];
73			return (unsigned long *)end;
74		}
75		/*
76		 * If this is a debug stack, and if it has a larger size than
77		 * the usual exception stacks, then 'stack' might still
78		 * be within the lower portion of the debug stack:
79		 */
80#if DEBUG_STKSZ > EXCEPTION_STKSZ
81		if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
82			unsigned j = N_EXCEPTION_STACKS - 1;
83
84			/*
85			 * Black magic. A large debug stack is composed of
86			 * multiple exception stack entries, which we
87			 * iterate through now. Dont look:
88			 */
89			do {
90				++j;
91				end -= EXCEPTION_STKSZ;
92				ids[j][4] = '1' + (j - N_EXCEPTION_STACKS);
93			} while (stack < end - EXCEPTION_STKSZ);
94			if (*usedp & (1U << j))
95				break;
96			*usedp |= 1U << j;
97			*idp = ids[j];
98			return (unsigned long *)end;
99		}
100#endif
101	}
102	return NULL;
103}
104
105/*
106 * x86-64 can have up to three kernel stacks:
107 * process stack
108 * interrupt stack
109 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
110 */
111
112static inline int valid_stack_ptr(struct thread_info *tinfo,
113			void *p, unsigned int size, void *end)
114{
115	void *t = tinfo;
116	if (end) {
117		if (p < end && p >= (end-THREAD_SIZE))
118			return 1;
119		else
120			return 0;
121	}
122	return p > t && p < t + THREAD_SIZE - size;
123}
124
125/* The form of the top of the frame on the stack */
126struct stack_frame {
127	struct stack_frame *next_frame;
128	unsigned long return_address;
129};
130
131static inline unsigned long
132print_context_stack(struct thread_info *tinfo,
133		unsigned long *stack, unsigned long bp,
134		const struct stacktrace_ops *ops, void *data,
135		unsigned long *end)
136{
137	struct stack_frame *frame = (struct stack_frame *)bp;
138
139	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
140		unsigned long addr;
141
142		addr = *stack;
143		if (__kernel_text_address(addr)) {
144			if ((unsigned long) stack == bp + 8) {
145				ops->address(data, addr, 1);
146				frame = frame->next_frame;
147				bp = (unsigned long) frame;
148			} else {
149				ops->address(data, addr, bp == 0);
150			}
151		}
152		stack++;
153	}
154	return bp;
155}
156
157void dump_trace(struct task_struct *task, struct pt_regs *regs,
158		unsigned long *stack, unsigned long bp,
159		const struct stacktrace_ops *ops, void *data)
160{
161	const unsigned cpu = get_cpu();
162	unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
163	unsigned used = 0;
164	struct thread_info *tinfo;
165
166	if (!task)
167		task = current;
168
169	if (!stack) {
170		unsigned long dummy;
171		stack = &dummy;
172		if (task && task != current)
173			stack = (unsigned long *)task->thread.sp;
174	}
175
176#ifdef CONFIG_FRAME_POINTER
177	if (!bp) {
178		if (task == current) {
179			/* Grab bp right from our regs */
180			asm("movq %%rbp, %0" : "=r" (bp) : );
181		} else {
182			/* bp is the last reg pushed by switch_to */
183			bp = *(unsigned long *) task->thread.sp;
184		}
185	}
186#endif
187
188	/*
189	 * Print function call entries in all stacks, starting at the
190	 * current stack address. If the stacks consist of nested
191	 * exceptions
192	 */
193	tinfo = task_thread_info(task);
194	for (;;) {
195		char *id;
196		unsigned long *estack_end;
197		estack_end = in_exception_stack(cpu, (unsigned long)stack,
198						&used, &id);
199
200		if (estack_end) {
201			if (ops->stack(data, id) < 0)
202				break;
203
204			bp = print_context_stack(tinfo, stack, bp, ops,
205							data, estack_end);
206			ops->stack(data, "<EOE>");
207			/*
208			 * We link to the next stack via the
209			 * second-to-last pointer (index -2 to end) in the
210			 * exception stack:
211			 */
212			stack = (unsigned long *) estack_end[-2];
213			continue;
214		}
215		if (irqstack_end) {
216			unsigned long *irqstack;
217			irqstack = irqstack_end -
218				(IRQSTACKSIZE - 64) / sizeof(*irqstack);
219
220			if (stack >= irqstack && stack < irqstack_end) {
221				if (ops->stack(data, "IRQ") < 0)
222					break;
223				bp = print_context_stack(tinfo, stack, bp,
224						ops, data, irqstack_end);
225				/*
226				 * We link to the next stack (which would be
227				 * the process stack normally) the last
228				 * pointer (index -1 to end) in the IRQ stack:
229				 */
230				stack = (unsigned long *) (irqstack_end[-1]);
231				irqstack_end = NULL;
232				ops->stack(data, "EOI");
233				continue;
234			}
235		}
236		break;
237	}
238
239	/*
240	 * This handles the process stack:
241	 */
242	bp = print_context_stack(tinfo, stack, bp, ops, data, NULL);
243	put_cpu();
244}
245EXPORT_SYMBOL(dump_trace);
246
247static void
248print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
249{
250	print_symbol(msg, symbol);
251	printk("\n");
252}
253
254static void print_trace_warning(void *data, char *msg)
255{
256	printk("%s\n", msg);
257}
258
259static int print_trace_stack(void *data, char *name)
260{
261	printk(" <%s> ", name);
262	return 0;
263}
264
265static void print_trace_address(void *data, unsigned long addr, int reliable)
266{
267	touch_nmi_watchdog();
268	printk_address(addr, reliable);
269}
270
271static const struct stacktrace_ops print_trace_ops = {
272	.warning = print_trace_warning,
273	.warning_symbol = print_trace_warning_symbol,
274	.stack = print_trace_stack,
275	.address = print_trace_address,
276};
277
278static void
279show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
280		unsigned long *stack, unsigned long bp, char *log_lvl)
281{
282	printk("Call Trace:\n");
283	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
284}
285
286void show_trace(struct task_struct *task, struct pt_regs *regs,
287		unsigned long *stack, unsigned long bp)
288{
289	show_trace_log_lvl(task, regs, stack, bp, "");
290}
291
292static void
293show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
294		unsigned long *sp, unsigned long bp, char *log_lvl)
295{
296	unsigned long *stack;
297	int i;
298	const int cpu = smp_processor_id();
299	unsigned long *irqstack_end =
300		(unsigned long *) (cpu_pda(cpu)->irqstackptr);
301	unsigned long *irqstack =
302		(unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE);
303
304	/*
305	 * debugging aid: "show_stack(NULL, NULL);" prints the
306	 * back trace for this cpu.
307	 */
308
309	if (sp == NULL) {
310		if (task)
311			sp = (unsigned long *)task->thread.sp;
312		else
313			sp = (unsigned long *)&sp;
314	}
315
316	stack = sp;
317	for (i = 0; i < kstack_depth_to_print; i++) {
318		if (stack >= irqstack && stack <= irqstack_end) {
319			if (stack == irqstack_end) {
320				stack = (unsigned long *) (irqstack_end[-1]);
321				printk(" <EOI> ");
322			}
323		} else {
324		if (((long) stack & (THREAD_SIZE-1)) == 0)
325			break;
326		}
327		if (i && ((i % 4) == 0))
328			printk("\n");
329		printk(" %016lx", *stack++);
330		touch_nmi_watchdog();
331	}
332	printk("\n");
333	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
334}
335
336void show_stack(struct task_struct *task, unsigned long *sp)
337{
338	show_stack_log_lvl(task, NULL, sp, 0, "");
339}
340
341/*
342 * The architecture-independent dump_stack generator
343 */
344void dump_stack(void)
345{
346	unsigned long bp = 0;
347	unsigned long stack;
348
349#ifdef CONFIG_FRAME_POINTER
350	if (!bp)
351		asm("movq %%rbp, %0" : "=r" (bp) : );
352#endif
353
354	printk("Pid: %d, comm: %.20s %s %s %.*s\n",
355		current->pid, current->comm, print_tainted(),
356		init_utsname()->release,
357		(int)strcspn(init_utsname()->version, " "),
358		init_utsname()->version);
359	show_trace(NULL, NULL, &stack, bp);
360}
361EXPORT_SYMBOL(dump_stack);
362
363void show_registers(struct pt_regs *regs)
364{
365	int i;
366	unsigned long sp;
367	const int cpu = smp_processor_id();
368	struct task_struct *cur = cpu_pda(cpu)->pcurrent;
369
370	sp = regs->sp;
371	printk("CPU %d ", cpu);
372	__show_regs(regs, 1);
373	printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
374		cur->comm, cur->pid, task_thread_info(cur), cur);
375
376	/*
377	 * When in-kernel, we also print out the stack and code at the
378	 * time of the fault..
379	 */
380	if (!user_mode(regs)) {
381		unsigned int code_prologue = code_bytes * 43 / 64;
382		unsigned int code_len = code_bytes;
383		unsigned char c;
384		u8 *ip;
385
386		printk("Stack: ");
387		show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
388				regs->bp, "");
389
390		printk(KERN_EMERG "Code: ");
391
392		ip = (u8 *)regs->ip - code_prologue;
393		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
394			/* try starting at RIP */
395			ip = (u8 *)regs->ip;
396			code_len = code_len - code_prologue + 1;
397		}
398		for (i = 0; i < code_len; i++, ip++) {
399			if (ip < (u8 *)PAGE_OFFSET ||
400					probe_kernel_address(ip, c)) {
401				printk(" Bad RIP value.");
402				break;
403			}
404			if (ip == (u8 *)regs->ip)
405				printk("<%02x> ", c);
406			else
407				printk("%02x ", c);
408		}
409	}
410	printk("\n");
411}
412
413int is_valid_bugaddr(unsigned long ip)
414{
415	unsigned short ud2;
416
417	if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
418		return 0;
419
420	return ud2 == 0x0b0f;
421}
422
423static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;
424static int die_owner = -1;
425static unsigned int die_nest_count;
426
427unsigned __kprobes long oops_begin(void)
428{
429	int cpu;
430	unsigned long flags;
431
432	oops_enter();
433
434	/* racy, but better than risking deadlock. */
435	raw_local_irq_save(flags);
436	cpu = smp_processor_id();
437	if (!__raw_spin_trylock(&die_lock)) {
438		if (cpu == die_owner)
439			/* nested oops. should stop eventually */;
440		else
441			__raw_spin_lock(&die_lock);
442	}
443	die_nest_count++;
444	die_owner = cpu;
445	console_verbose();
446	bust_spinlocks(1);
447	return flags;
448}
449
450void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
451{
452	die_owner = -1;
453	bust_spinlocks(0);
454	die_nest_count--;
455	if (!die_nest_count)
456		/* Nest count reaches zero, release the lock. */
457		__raw_spin_unlock(&die_lock);
458	raw_local_irq_restore(flags);
459	if (!regs) {
460		oops_exit();
461		return;
462	}
463	if (in_interrupt())
464		panic("Fatal exception in interrupt");
465	if (panic_on_oops)
466		panic("Fatal exception");
467	oops_exit();
468	do_exit(signr);
469}
470
471int __kprobes __die(const char *str, struct pt_regs *regs, long err)
472{
473	printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff, ++die_counter);
474#ifdef CONFIG_PREEMPT
475	printk("PREEMPT ");
476#endif
477#ifdef CONFIG_SMP
478	printk("SMP ");
479#endif
480#ifdef CONFIG_DEBUG_PAGEALLOC
481	printk("DEBUG_PAGEALLOC");
482#endif
483	printk("\n");
484	if (notify_die(DIE_OOPS, str, regs, err,
485			current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
486		return 1;
487
488	show_registers(regs);
489	add_taint(TAINT_DIE);
490	/* Executive summary in case the oops scrolled away */
491	printk(KERN_ALERT "RIP ");
492	printk_address(regs->ip, 1);
493	printk(" RSP <%016lx>\n", regs->sp);
494	if (kexec_should_crash(current))
495		crash_kexec(regs);
496	return 0;
497}
498
499void die(const char *str, struct pt_regs *regs, long err)
500{
501	unsigned long flags = oops_begin();
502
503	if (!user_mode(regs))
504		report_bug(regs->ip, regs);
505
506	if (__die(str, regs, err))
507		regs = NULL;
508	oops_end(flags, regs, SIGSEGV);
509}
510
511notrace __kprobes void
512die_nmi(char *str, struct pt_regs *regs, int do_panic)
513{
514	unsigned long flags;
515
516	if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
517		return;
518
519	flags = oops_begin();
520	/*
521	 * We are in trouble anyway, lets at least try
522	 * to get a message out.
523	 */
524	printk(KERN_EMERG "%s", str);
525	printk(" on CPU%d, ip %08lx, registers:\n",
526		smp_processor_id(), regs->ip);
527	show_registers(regs);
528	if (kexec_should_crash(current))
529		crash_kexec(regs);
530	if (do_panic || panic_on_oops)
531		panic("Non maskable interrupt");
532	oops_end(flags, NULL, SIGBUS);
533	nmi_exit();
534	local_irq_enable();
535	do_exit(SIGBUS);
536}
537
538static int __init oops_setup(char *s)
539{
540	if (!s)
541		return -EINVAL;
542	if (!strcmp(s, "panic"))
543		panic_on_oops = 1;
544	return 0;
545}
546early_param("oops", oops_setup);
547
548static int __init kstack_setup(char *s)
549{
550	if (!s)
551		return -EINVAL;
552	kstack_depth_to_print = simple_strtoul(s, NULL, 0);
553	return 0;
554}
555early_param("kstack", kstack_setup);
556
557static int __init code_bytes_setup(char *s)
558{
559	code_bytes = simple_strtoul(s, NULL, 0);
560	if (code_bytes > 8192)
561		code_bytes = 8192;
562
563	return 1;
564}
565__setup("code_bytes=", code_bytes_setup);
566