[deliverable/linux.git] / arch / x86 / kernel / dumpstack.c

/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
 */
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/utsname.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/ftrace.h>
#include <linux/kexec.h>
#include <linux/bug.h>
#include <linux/nmi.h>
#include <linux/sysfs.h>

#include <asm/stacktrace.h>


int panic_on_unrecovered_nmi;
int panic_on_io_nmi;
unsigned int code_bytes = 64;
int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
static int die_counter;

static void printk_stack_address(unsigned long address, int reliable,
		void *data)
{
	printk("%s [<%p>] %s%pB\n",
		(char *)data, (void *)address, reliable ? "" : "? ",
		(void *)address);
}

void printk_address(unsigned long address)
{
	pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
}

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static void
print_ftrace_graph_addr(unsigned long addr, void *data,
			const struct stacktrace_ops *ops,
			struct task_struct *task, int *graph)
{
	unsigned long ret_addr;
	int index;

	if (addr != (unsigned long)return_to_handler)
		return;

	index = task->curr_ret_stack;

	if (!task->ret_stack || index < *graph)
		return;

	index -= *graph;
	ret_addr = task->ret_stack[index].ret;

	ops->address(data, ret_addr, 1);

	(*graph)++;
}
#else
static inline void
print_ftrace_graph_addr(unsigned long addr, void *data,
			const struct stacktrace_ops *ops,
			struct task_struct *task, int *graph)
{ }
#endif

/*
 * x86-64 can have up to three kernel stacks:
 * process stack
 * interrupt stack
 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
 */

static inline int valid_stack_ptr(struct task_struct *task,
			void *p, unsigned int size, void *end)
{
	void *t = task_stack_page(task);
	if (end) {
		if (p < end && p >= (end-THREAD_SIZE))
			return 1;
		else
			return 0;
	}
	return p >= t && p < t + THREAD_SIZE - size;
}

unsigned long
print_context_stack(struct task_struct *task,
		unsigned long *stack, unsigned long bp,
		const struct stacktrace_ops *ops, void *data,
		unsigned long *end, int *graph)
{
	struct stack_frame *frame = (struct stack_frame *)bp;

	/*
	 * If we overflowed the stack into a guard page, jump back to the
	 * bottom of the usable stack.
	 */
	if ((unsigned long)task_stack_page(task) - (unsigned long)stack <
	    PAGE_SIZE)
		stack = (unsigned long *)task_stack_page(task);

	while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
		unsigned long addr;

		addr = *stack;
		if (__kernel_text_address(addr)) {
			if ((unsigned long) stack == bp + sizeof(long)) {
				ops->address(data, addr, 1);
				frame = frame->next_frame;
				bp = (unsigned long) frame;
			} else {
				ops->address(data, addr, 0);
			}
			print_ftrace_graph_addr(addr, data, ops, task, graph);
		}
		stack++;
	}
	return bp;
}
EXPORT_SYMBOL_GPL(print_context_stack);

unsigned long
print_context_stack_bp(struct task_struct *task,
		       unsigned long *stack, unsigned long bp,
		       const struct stacktrace_ops *ops, void *data,
		       unsigned long *end, int *graph)
{
	struct stack_frame *frame = (struct stack_frame *)bp;
	unsigned long *ret_addr = &frame->return_address;

	while (valid_stack_ptr(task, ret_addr, sizeof(*ret_addr), end)) {
		unsigned long addr = *ret_addr;

		if (!__kernel_text_address(addr))
			break;

		if (ops->address(data, addr, 1))
			break;
		frame = frame->next_frame;
		ret_addr = &frame->return_address;
		print_ftrace_graph_addr(addr, data, ops, task, graph);
	}

	return (unsigned long)frame;
}
EXPORT_SYMBOL_GPL(print_context_stack_bp);

static int print_trace_stack(void *data, char *name)
{
	printk("%s <%s> ", (char *)data, name);
	return 0;
}

/*
 * Print one address/symbol entries per line.
 */
static int print_trace_address(void *data, unsigned long addr, int reliable)
{
	touch_nmi_watchdog();
	printk_stack_address(addr, reliable, data);
	return 0;
}

static const struct stacktrace_ops print_trace_ops = {
	.stack			= print_trace_stack,
	.address		= print_trace_address,
	.walk_stack		= print_context_stack,
};

void
show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
		unsigned long *stack, unsigned long bp, char *log_lvl)
{
	printk("%sCall Trace:\n", log_lvl);
	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
}

void show_trace(struct task_struct *task, struct pt_regs *regs,
		unsigned long *stack, unsigned long bp)
{
	show_trace_log_lvl(task, regs, stack, bp, "");
}

void show_stack(struct task_struct *task, unsigned long *sp)
{
	unsigned long bp = 0;
	unsigned long stack;

	/*
	 * Stack frames below this one aren't interesting.  Don't show them
	 * if we're printing for %current.
	 */
	if (!sp && (!task || task == current)) {
		sp = &stack;
		bp = stack_frame(current, NULL);
	}

	show_stack_log_lvl(task, NULL, sp, bp, "");
}

static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
static int die_owner = -1;
static unsigned int die_nest_count;

unsigned long oops_begin(void)
{
	int cpu;
	unsigned long flags;

	oops_enter();

	/* racy, but better than risking deadlock. */
	raw_local_irq_save(flags);
	cpu = smp_processor_id();
	if (!arch_spin_trylock(&die_lock)) {
		if (cpu == die_owner)
			/* nested oops. should stop eventually */;
		else
			arch_spin_lock(&die_lock);
	}
	die_nest_count++;
	die_owner = cpu;
	console_verbose();
	bust_spinlocks(1);
	return flags;
}
EXPORT_SYMBOL_GPL(oops_begin);
NOKPROBE_SYMBOL(oops_begin);

void __noreturn rewind_stack_do_exit(int signr);

void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
{
	if (regs && kexec_should_crash(current))
		crash_kexec(regs);

	bust_spinlocks(0);
	die_owner = -1;
	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
	die_nest_count--;
	if (!die_nest_count)
		/* Nest count reaches zero, release the lock. */
		arch_spin_unlock(&die_lock);
	raw_local_irq_restore(flags);
	oops_exit();

	if (!signr)
		return;
	if (in_interrupt())
		panic("Fatal exception in interrupt");
	if (panic_on_oops)
		panic("Fatal exception");

	/*
	 * We're not going to return, but we might be on an IST stack or
	 * have very little stack space left.  Rewind the stack and kill
	 * the task.
	 */
	rewind_stack_do_exit(signr);
}
NOKPROBE_SYMBOL(oops_end);

int __die(const char *str, struct pt_regs *regs, long err)
{
#ifdef CONFIG_X86_32
	unsigned short ss;
	unsigned long sp;
#endif
	printk(KERN_DEFAULT
	       "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",
	       IS_ENABLED(CONFIG_SMP)     ? " SMP"             : "",
	       debug_pagealloc_enabled()  ? " DEBUG_PAGEALLOC" : "",
	       IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "");

	if (notify_die(DIE_OOPS, str, regs, err,
			current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
		return 1;

	print_modules();
	show_regs(regs);
#ifdef CONFIG_X86_32
	if (user_mode(regs)) {
		sp = regs->sp;
		ss = regs->ss & 0xffff;
	} else {
		sp = kernel_stack_pointer(regs);
		savesegment(ss, ss);
	}
	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
	print_symbol("%s", regs->ip);
	printk(" SS:ESP %04x:%08lx\n", ss, sp);
#else
	/* Executive summary in case the oops scrolled away */
	printk(KERN_ALERT "RIP ");
	printk_address(regs->ip);
	printk(" RSP <%016lx>\n", regs->sp);
#endif
	return 0;
}
NOKPROBE_SYMBOL(__die);

/*
 * This is gone through when something in the kernel has done something bad
 * and is about to be terminated:
 */
void die(const char *str, struct pt_regs *regs, long err)
{
	unsigned long flags = oops_begin();
	int sig = SIGSEGV;

	if (!user_mode(regs))
		report_bug(regs->ip, regs);

	if (__die(str, regs, err))
		sig = 0;
	oops_end(flags, regs, sig);
}

static int __init kstack_setup(char *s)
{
	ssize_t ret;
	unsigned long val;

	if (!s)
		return -EINVAL;

	ret = kstrtoul(s, 0, &val);
	if (ret)
		return ret;
	kstack_depth_to_print = val;
	return 0;
}
early_param("kstack", kstack_setup);

static int __init code_bytes_setup(char *s)
{
	ssize_t ret;
	unsigned long val;

	if (!s)
		return -EINVAL;

	ret = kstrtoul(s, 0, &val);
	if (ret)
		return ret;

	code_bytes = val;
	if (code_bytes > 8192)
		code_bytes = 8192;

	return 1;
}
__setup("code_bytes=", code_bytes_setup);
Commit	Line	Data
878719e8 NH	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>
712406a6	13	#include <linux/ftrace.h>
878719e8 NH	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
878719e8 NH	21
878719e8 NH	22	int panic_on_unrecovered_nmi;
5211a242	23	int panic_on_io_nmi;
878719e8 NH	24	unsigned int code_bytes = 64;
	25	int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
	26	static int die_counter;
	27
1fc7f61c AS	28	static void printk_stack_address(unsigned long address, int reliable,
1fc7f61c AS	29	void *data)
878719e8	30	{
1fc7f61c AS	31	printk("%s [<%p>] %s%pB\n",
	32	(char )data, (void )address, reliable ? "" : "? ",
	33	(void *)address);
878719e8 NH	34	}
878719e8 NH	35
5f01c988 JS	36	void printk_address(unsigned long address)
	37	{
	38	pr_cont(" [<%p>] %pS\n", (void )address, (void )address);
	39	}
	40
7ee991fb SR	41	#ifdef CONFIG_FUNCTION_GRAPH_TRACER
	42	static void
	43	print_ftrace_graph_addr(unsigned long addr, void *data,
	44	const struct stacktrace_ops *ops,
da01e18a	45	struct task_struct task, int graph)
7ee991fb	46	{
7ee991fb	47	unsigned long ret_addr;
65c0ff40	48	int index;
7ee991fb SR	49
	50	if (addr != (unsigned long)return_to_handler)
	51	return;
	52
65c0ff40 HD	53	index = task->curr_ret_stack;
65c0ff40 HD	54
7ee991fb SR	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
	67	print_ftrace_graph_addr(unsigned long addr, void *data,
	68	const struct stacktrace_ops *ops,
da01e18a	69	struct task_struct task, int graph)
7ee991fb SR	70	{ }
	71	#endif
	72
878719e8 NH	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
da01e18a	80	static inline int valid_stack_ptr(struct task_struct *task,
878719e8 NH	81	void p, unsigned int size, void end)
878719e8 NH	82	{
aca9c293	83	void *t = task_stack_page(task);
878719e8 NH	84	if (end) {
	85	if (p < end && p >= (end-THREAD_SIZE))
	86	return 1;
	87	else
	88	return 0;
	89	}
9a2e9da3	90	return p >= t && p < t + THREAD_SIZE - size;
878719e8 NH	91	}
	92
	93	unsigned long
da01e18a	94	print_context_stack(struct task_struct *task,
878719e8 NH	95	unsigned long *stack, unsigned long bp,
878719e8 NH	96	const struct stacktrace_ops ops, void data,
7ee991fb	97	unsigned long end, int graph)
878719e8 NH	98	{
	99	struct stack_frame frame = (struct stack_frame )bp;
	100
9a2e9da3 AL	101	/*
	102	* If we overflowed the stack into a guard page, jump back to the
	103	* bottom of the usable stack.
	104	*/
	105	if ((unsigned long)task_stack_page(task) - (unsigned long)stack <
	106	PAGE_SIZE)
	107	stack = (unsigned long *)task_stack_page(task);
	108
da01e18a	109	while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
878719e8 NH	110	unsigned long addr;
	111
	112	addr = *stack;
	113	if (__kernel_text_address(addr)) {
	114	if ((unsigned long) stack == bp + sizeof(long)) {
	115	ops->address(data, addr, 1);
	116	frame = frame->next_frame;
	117	bp = (unsigned long) frame;
	118	} else {
2c344e9d	119	ops->address(data, addr, 0);
878719e8	120	}
da01e18a	121	print_ftrace_graph_addr(addr, data, ops, task, graph);
878719e8 NH	122	}
	123	stack++;
	124	}
	125	return bp;
	126	}
06d65bda FW	127	EXPORT_SYMBOL_GPL(print_context_stack);
	128
	129	unsigned long
da01e18a	130	print_context_stack_bp(struct task_struct *task,
06d65bda FW	131	unsigned long *stack, unsigned long bp,
	132	const struct stacktrace_ops ops, void data,
	133	unsigned long end, int graph)
	134	{
	135	struct stack_frame frame = (struct stack_frame )bp;
	136	unsigned long *ret_addr = &frame->return_address;
	137
da01e18a	138	while (valid_stack_ptr(task, ret_addr, sizeof(*ret_addr), end)) {
06d65bda FW	139	unsigned long addr = *ret_addr;
06d65bda FW	140
c2c5d45d FW	141	if (!__kernel_text_address(addr))
	142	break;
	143
568b329a AS	144	if (ops->address(data, addr, 1))
568b329a AS	145	break;
c2c5d45d FW	146	frame = frame->next_frame;
c2c5d45d FW	147	ret_addr = &frame->return_address;
da01e18a	148	print_ftrace_graph_addr(addr, data, ops, task, graph);
06d65bda	149	}
c2c5d45d	150
06d65bda FW	151	return (unsigned long)frame;
	152	}
	153	EXPORT_SYMBOL_GPL(print_context_stack_bp);
878719e8	154
878719e8 NH	155	static int print_trace_stack(void data, char name)
	156	{
	157	printk("%s <%s> ", (char *)data, name);
	158	return 0;
	159	}
	160
	161	/*
	162	* Print one address/symbol entries per line.
	163	*/
568b329a	164	static int print_trace_address(void *data, unsigned long addr, int reliable)
878719e8 NH	165	{
878719e8 NH	166	touch_nmi_watchdog();
1fc7f61c	167	printk_stack_address(addr, reliable, data);
568b329a	168	return 0;
878719e8 NH	169	}
	170
	171	static const struct stacktrace_ops print_trace_ops = {
06d65bda FW	172	.stack = print_trace_stack,
06d65bda FW	173	.address = print_trace_address,
61c1917f	174	.walk_stack = print_context_stack,
878719e8 NH	175	};
	176
	177	void
	178	show_trace_log_lvl(struct task_struct task, struct pt_regs regs,
e8e999cf	179	unsigned long stack, unsigned long bp, char log_lvl)
878719e8 NH	180	{
878719e8 NH	181	printk("%sCall Trace:\n", log_lvl);
e8e999cf	182	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
878719e8 NH	183	}
	184
	185	void show_trace(struct task_struct task, struct pt_regs regs,
e8e999cf	186	unsigned long *stack, unsigned long bp)
878719e8	187	{
e8e999cf	188	show_trace_log_lvl(task, regs, stack, bp, "");
878719e8 NH	189	}
	190
	191	void show_stack(struct task_struct task, unsigned long sp)
	192	{
a77f2a4e TH	193	unsigned long bp = 0;
	194	unsigned long stack;
	195
	196	/*
	197	* Stack frames below this one aren't interesting. Don't show them
	198	* if we're printing for %current.
	199	*/
	200	if (!sp && (!task \|\| task == current)) {
	201	sp = &stack;
	202	bp = stack_frame(current, NULL);
	203	}
	204
	205	show_stack_log_lvl(task, NULL, sp, bp, "");
878719e8 NH	206	}
878719e8 NH	207
edc35bd7	208	static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
878719e8 NH	209	static int die_owner = -1;
	210	static unsigned int die_nest_count;
	211
9326638c	212	unsigned long oops_begin(void)
878719e8 NH	213	{
	214	int cpu;
	215	unsigned long flags;
	216
	217	oops_enter();
	218
	219	/* racy, but better than risking deadlock. */
	220	raw_local_irq_save(flags);
	221	cpu = smp_processor_id();
0199c4e6	222	if (!arch_spin_trylock(&die_lock)) {
878719e8 NH	223	if (cpu == die_owner)
	224	/* nested oops. should stop eventually */;
	225	else
0199c4e6	226	arch_spin_lock(&die_lock);
878719e8 NH	227	}
	228	die_nest_count++;
	229	die_owner = cpu;
	230	console_verbose();
	231	bust_spinlocks(1);
	232	return flags;
	233	}
81e88fdc	234	EXPORT_SYMBOL_GPL(oops_begin);
9326638c	235	NOKPROBE_SYMBOL(oops_begin);
878719e8	236
2deb4be2 AL	237	void __noreturn rewind_stack_do_exit(int signr);
2deb4be2 AL	238
9326638c	239	void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
878719e8 NH	240	{
	241	if (regs && kexec_should_crash(current))
	242	crash_kexec(regs);
	243
	244	bust_spinlocks(0);
	245	die_owner = -1;
373d4d09	246	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
878719e8 NH	247	die_nest_count--;
	248	if (!die_nest_count)
	249	/* Nest count reaches zero, release the lock. */
0199c4e6	250	arch_spin_unlock(&die_lock);
878719e8 NH	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");
2deb4be2 AL	260
	261	/*
	262	* We're not going to return, but we might be on an IST stack or
	263	* have very little stack space left. Rewind the stack and kill
	264	* the task.
	265	*/
	266	rewind_stack_do_exit(signr);
878719e8	267	}
9326638c	268	NOKPROBE_SYMBOL(oops_end);
878719e8	269
9326638c	270	int __die(const char str, struct pt_regs regs, long err)
878719e8 NH	271	{
	272	#ifdef CONFIG_X86_32
	273	unsigned short ss;
	274	unsigned long sp;
	275	#endif
b0f4c4b3	276	printk(KERN_DEFAULT
8fad7ec5 RV	277	"%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
	278	IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
	279	IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
	280	debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
	281	IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "");
	282
878719e8	283	if (notify_die(DIE_OOPS, str, regs, err,
51e7dc70	284	current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
878719e8 NH	285	return 1;
878719e8 NH	286
0fa0e2f0	287	print_modules();
57da8b96	288	show_regs(regs);
878719e8	289	#ifdef CONFIG_X86_32
f39b6f0e	290	if (user_mode(regs)) {
878719e8 NH	291	sp = regs->sp;
878719e8 NH	292	ss = regs->ss & 0xffff;
a343c75d PA	293	} else {
	294	sp = kernel_stack_pointer(regs);
	295	savesegment(ss, ss);
878719e8 NH	296	}
	297	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
	298	print_symbol("%s", regs->ip);
	299	printk(" SS:ESP %04x:%08lx\n", ss, sp);
	300	#else
	301	/* Executive summary in case the oops scrolled away */
	302	printk(KERN_ALERT "RIP ");
5f01c988	303	printk_address(regs->ip);
878719e8 NH	304	printk(" RSP <%016lx>\n", regs->sp);
	305	#endif
	306	return 0;
	307	}
9326638c	308	NOKPROBE_SYMBOL(__die);
878719e8 NH	309
	310	/*
	311	* This is gone through when something in the kernel has done something bad
	312	* and is about to be terminated:
	313	*/
	314	void die(const char str, struct pt_regs regs, long err)
	315	{
	316	unsigned long flags = oops_begin();
	317	int sig = SIGSEGV;
	318
f39b6f0e	319	if (!user_mode(regs))
878719e8 NH	320	report_bug(regs->ip, regs);
	321
	322	if (__die(str, regs, err))
	323	sig = 0;
	324	oops_end(flags, regs, sig);
	325	}
	326
878719e8 NH	327	static int __init kstack_setup(char *s)
878719e8 NH	328	{
363f7ce3 SK	329	ssize_t ret;
	330	unsigned long val;
	331
878719e8 NH	332	if (!s)
878719e8 NH	333	return -EINVAL;
363f7ce3 SK	334
	335	ret = kstrtoul(s, 0, &val);
	336	if (ret)
	337	return ret;
	338	kstack_depth_to_print = val;
878719e8 NH	339	return 0;
	340	}
	341	early_param("kstack", kstack_setup);
	342
	343	static int __init code_bytes_setup(char *s)
	344	{
363f7ce3 SK	345	ssize_t ret;
	346	unsigned long val;
	347
	348	if (!s)
	349	return -EINVAL;
	350
	351	ret = kstrtoul(s, 0, &val);
	352	if (ret)
	353	return ret;
	354
	355	code_bytes = val;
878719e8 NH	356	if (code_bytes > 8192)
	357	code_bytes = 8192;
	358
	359	return 1;
	360	}
	361	__setup("code_bytes=", code_bytes_setup);