/arch/x86/kernel/dumpstack.c

  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
 23int panic_on_unrecovered_nmi;
 24int panic_on_io_nmi;
 25unsigned int code_bytes = 64;
 26int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
 27static int die_counter;
 28
 29void 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
 36static void
 37print_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
 59static inline void
 60print_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
 73static 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
 86unsigned long
 87print_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}
112EXPORT_SYMBOL_GPL(print_context_stack);
113
114unsigned long
115print_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}
137EXPORT_SYMBOL_GPL(print_context_stack_bp);
138
139
140static void
141print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
142{
143	printk(data);
144	print_symbol(msg, symbol);
145	printk("\n");
146}
147
148static void print_trace_warning(void *data, char *msg)
149{
150	printk("%s%s\n", (char *)data, msg);
151}
152
153static 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 */
162static 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
169static 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
177void
178show_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
185void 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
191void 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 */
199void 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}
216EXPORT_SYMBOL(dump_stack);
217
218static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
219static int die_owner = -1;
220static unsigned int die_nest_count;
221
222unsigned __kprobes long oops_begin(void)
223{
224	int cpu;
225	unsigned long flags;
226
227	oops_enter();
228
229	/* racy, but better than risking deadlock. */
230	raw_local_irq_save(flags);
231	cpu = smp_processor_id();
232	if (!arch_spin_trylock(&die_lock)) {
233		if (cpu == die_owner)
234			/* nested oops. should stop eventually */;
235		else
236			arch_spin_lock(&die_lock);
237	}
238	die_nest_count++;
239	die_owner = cpu;
240	console_verbose();
241	bust_spinlocks(1);
242	return flags;
243}
244
245void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
246{
247	if (regs && kexec_should_crash(current))
248		crash_kexec(regs);
249
250	bust_spinlocks(0);
251	die_owner = -1;
252	add_taint(TAINT_DIE);
253	die_nest_count--;
254	if (!die_nest_count)
255		/* Nest count reaches zero, release the lock. */
256		arch_spin_unlock(&die_lock);
257	raw_local_irq_restore(flags);
258	oops_exit();
259
260	if (!signr)
261		return;
262	if (in_interrupt())
263		panic("Fatal exception in interrupt");
264	if (panic_on_oops)
265		panic("Fatal exception");
266	do_exit(signr);
267}
268
269int __kprobes __die(const char *str, struct pt_regs *regs, long err)
270{
271#ifdef CONFIG_X86_32
272	unsigned short ss;
273	unsigned long sp;
274#endif
275	printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
276#ifdef CONFIG_PREEMPT
277	printk("PREEMPT ");
278#endif
279#ifdef CONFIG_SMP
280	printk("SMP ");
281#endif
282#ifdef CONFIG_DEBUG_PAGEALLOC
283	printk("DEBUG_PAGEALLOC");
284#endif
285	printk("\n");
286	sysfs_printk_last_file();
287	if (notify_die(DIE_OOPS, str, regs, err,
288			current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
289		return 1;
290
291	show_registers(regs);
292#ifdef CONFIG_X86_32
293	if (user_mode_vm(regs)) {
294		sp = regs->sp;
295		ss = regs->ss & 0xffff;
296	} else {
297		sp = kernel_stack_pointer(regs);
298		savesegment(ss, ss);
299	}
300	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
301	print_symbol("%s", regs->ip);
302	printk(" SS:ESP %04x:%08lx\n", ss, sp);
303#else
304	/* Executive summary in case the oops scrolled away */
305	printk(KERN_ALERT "RIP ");
306	printk_address(regs->ip, 1);
307	printk(" RSP <%016lx>\n", regs->sp);
308#endif
309	return 0;
310}
311
312/*
313 * This is gone through when something in the kernel has done something bad
314 * and is about to be terminated:
315 */
316void die(const char *str, struct pt_regs *regs, long err)
317{
318	unsigned long flags = oops_begin();
319	int sig = SIGSEGV;
320
321	if (!user_mode_vm(regs))
322		report_bug(regs->ip, regs);
323
324	if (__die(str, regs, err))
325		sig = 0;
326	oops_end(flags, regs, sig);
327}
328
329void notrace __kprobes
330die_nmi(char *str, struct pt_regs *regs, int do_panic)
331{
332	unsigned long flags;
333
334	if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
335		return;
336
337	/*
338	 * We are in trouble anyway, lets at least try
339	 * to get a message out.
340	 */
341	flags = oops_begin();
342	printk(KERN_EMERG "%s", str);
343	printk(" on CPU%d, ip %08lx, registers:\n",
344		smp_processor_id(), regs->ip);
345	show_registers(regs);
346	oops_end(flags, regs, 0);
347	if (do_panic || panic_on_oops)
348		panic("Non maskable interrupt");
349	nmi_exit();
350	local_irq_enable();
351	do_exit(SIGBUS);
352}
353
354static int __init oops_setup(char *s)
355{
356	if (!s)
357		return -EINVAL;
358	if (!strcmp(s, "panic"))
359		panic_on_oops = 1;
360	return 0;
361}
362early_param("oops", oops_setup);
363
364static int __init kstack_setup(char *s)
365{
366	if (!s)
367		return -EINVAL;
368	kstack_depth_to_print = simple_strtoul(s, NULL, 0);
369	return 0;
370}
371early_param("kstack", kstack_setup);
372
373static int __init code_bytes_setup(char *s)
374{
375	code_bytes = simple_strtoul(s, NULL, 0);
376	if (code_bytes > 8192)
377		code_bytes = 8192;
378
379	return 1;
380}
381__setup("code_bytes=", code_bytes_setup);