dump_stack: consolidate dump_stack() implementations and unify their behaviors
[linux-3.10.git] / 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
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         pr_cont(" [<%p>] %s%pB\n",
31                 (void *)address, 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;
41         unsigned long ret_addr;
42         int index;
43
44         if (addr != (unsigned long)return_to_handler)
45                 return;
46
47         task = tinfo->task;
48         index = task->curr_ret_stack;
49
50         if (!task->ret_stack || index < *graph)
51                 return;
52
53         index -= *graph;
54         ret_addr = task->ret_stack[index].ret;
55
56         ops->address(data, ret_addr, 1);
57
58         (*graph)++;
59 }
60 #else
61 static inline void
62 print_ftrace_graph_addr(unsigned long addr, void *data,
63                         const struct stacktrace_ops *ops,
64                         struct thread_info *tinfo, int *graph)
65 { }
66 #endif
67
68 /*
69  * x86-64 can have up to three kernel stacks:
70  * process stack
71  * interrupt stack
72  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
73  */
74
75 static inline int valid_stack_ptr(struct thread_info *tinfo,
76                         void *p, unsigned int size, void *end)
77 {
78         void *t = tinfo;
79         if (end) {
80                 if (p < end && p >= (end-THREAD_SIZE))
81                         return 1;
82                 else
83                         return 0;
84         }
85         return p > t && p < t + THREAD_SIZE - size;
86 }
87
88 unsigned long
89 print_context_stack(struct thread_info *tinfo,
90                 unsigned long *stack, unsigned long bp,
91                 const struct stacktrace_ops *ops, void *data,
92                 unsigned long *end, int *graph)
93 {
94         struct stack_frame *frame = (struct stack_frame *)bp;
95
96         while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
97                 unsigned long addr;
98
99                 addr = *stack;
100                 if (__kernel_text_address(addr)) {
101                         if ((unsigned long) stack == bp + sizeof(long)) {
102                                 ops->address(data, addr, 1);
103                                 frame = frame->next_frame;
104                                 bp = (unsigned long) frame;
105                         } else {
106                                 ops->address(data, addr, 0);
107                         }
108                         print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
109                 }
110                 stack++;
111         }
112         return bp;
113 }
114 EXPORT_SYMBOL_GPL(print_context_stack);
115
116 unsigned long
117 print_context_stack_bp(struct thread_info *tinfo,
118                        unsigned long *stack, unsigned long bp,
119                        const struct stacktrace_ops *ops, void *data,
120                        unsigned long *end, int *graph)
121 {
122         struct stack_frame *frame = (struct stack_frame *)bp;
123         unsigned long *ret_addr = &frame->return_address;
124
125         while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
126                 unsigned long addr = *ret_addr;
127
128                 if (!__kernel_text_address(addr))
129                         break;
130
131                 ops->address(data, addr, 1);
132                 frame = frame->next_frame;
133                 ret_addr = &frame->return_address;
134                 print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
135         }
136
137         return (unsigned long)frame;
138 }
139 EXPORT_SYMBOL_GPL(print_context_stack_bp);
140
141 static int print_trace_stack(void *data, char *name)
142 {
143         printk("%s <%s> ", (char *)data, name);
144         return 0;
145 }
146
147 /*
148  * Print one address/symbol entries per line.
149  */
150 static void print_trace_address(void *data, unsigned long addr, int reliable)
151 {
152         touch_nmi_watchdog();
153         printk(data);
154         printk_address(addr, reliable);
155 }
156
157 static const struct stacktrace_ops print_trace_ops = {
158         .stack                  = print_trace_stack,
159         .address                = print_trace_address,
160         .walk_stack             = print_context_stack,
161 };
162
163 void
164 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
165                 unsigned long *stack, unsigned long bp, char *log_lvl)
166 {
167         printk("%sCall Trace:\n", log_lvl);
168         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
169 }
170
171 void show_trace(struct task_struct *task, struct pt_regs *regs,
172                 unsigned long *stack, unsigned long bp)
173 {
174         show_trace_log_lvl(task, regs, stack, bp, "");
175 }
176
177 void show_stack(struct task_struct *task, unsigned long *sp)
178 {
179         unsigned long bp = 0;
180         unsigned long stack;
181
182         /*
183          * Stack frames below this one aren't interesting.  Don't show them
184          * if we're printing for %current.
185          */
186         if (!sp && (!task || task == current)) {
187                 sp = &stack;
188                 bp = stack_frame(current, NULL);
189         }
190
191         show_stack_log_lvl(task, NULL, sp, bp, "");
192 }
193
194 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
195 static int die_owner = -1;
196 static unsigned int die_nest_count;
197
198 unsigned __kprobes long oops_begin(void)
199 {
200         int cpu;
201         unsigned long flags;
202
203         oops_enter();
204
205         /* racy, but better than risking deadlock. */
206         raw_local_irq_save(flags);
207         cpu = smp_processor_id();
208         if (!arch_spin_trylock(&die_lock)) {
209                 if (cpu == die_owner)
210                         /* nested oops. should stop eventually */;
211                 else
212                         arch_spin_lock(&die_lock);
213         }
214         die_nest_count++;
215         die_owner = cpu;
216         console_verbose();
217         bust_spinlocks(1);
218         return flags;
219 }
220 EXPORT_SYMBOL_GPL(oops_begin);
221
222 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
223 {
224         if (regs && kexec_should_crash(current))
225                 crash_kexec(regs);
226
227         bust_spinlocks(0);
228         die_owner = -1;
229         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
230         die_nest_count--;
231         if (!die_nest_count)
232                 /* Nest count reaches zero, release the lock. */
233                 arch_spin_unlock(&die_lock);
234         raw_local_irq_restore(flags);
235         oops_exit();
236
237         if (!signr)
238                 return;
239         if (in_interrupt())
240                 panic("Fatal exception in interrupt");
241         if (panic_on_oops)
242                 panic("Fatal exception");
243         do_exit(signr);
244 }
245
246 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
247 {
248 #ifdef CONFIG_X86_32
249         unsigned short ss;
250         unsigned long sp;
251 #endif
252         printk(KERN_DEFAULT
253                "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
254 #ifdef CONFIG_PREEMPT
255         printk("PREEMPT ");
256 #endif
257 #ifdef CONFIG_SMP
258         printk("SMP ");
259 #endif
260 #ifdef CONFIG_DEBUG_PAGEALLOC
261         printk("DEBUG_PAGEALLOC");
262 #endif
263         printk("\n");
264         if (notify_die(DIE_OOPS, str, regs, err,
265                         current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
266                 return 1;
267
268         print_modules();
269         show_regs(regs);
270 #ifdef CONFIG_X86_32
271         if (user_mode_vm(regs)) {
272                 sp = regs->sp;
273                 ss = regs->ss & 0xffff;
274         } else {
275                 sp = kernel_stack_pointer(regs);
276                 savesegment(ss, ss);
277         }
278         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
279         print_symbol("%s", regs->ip);
280         printk(" SS:ESP %04x:%08lx\n", ss, sp);
281 #else
282         /* Executive summary in case the oops scrolled away */
283         printk(KERN_ALERT "RIP ");
284         printk_address(regs->ip, 1);
285         printk(" RSP <%016lx>\n", regs->sp);
286 #endif
287         return 0;
288 }
289
290 /*
291  * This is gone through when something in the kernel has done something bad
292  * and is about to be terminated:
293  */
294 void die(const char *str, struct pt_regs *regs, long err)
295 {
296         unsigned long flags = oops_begin();
297         int sig = SIGSEGV;
298
299         if (!user_mode_vm(regs))
300                 report_bug(regs->ip, regs);
301
302         if (__die(str, regs, err))
303                 sig = 0;
304         oops_end(flags, regs, sig);
305 }
306
307 static int __init kstack_setup(char *s)
308 {
309         ssize_t ret;
310         unsigned long val;
311
312         if (!s)
313                 return -EINVAL;
314
315         ret = kstrtoul(s, 0, &val);
316         if (ret)
317                 return ret;
318         kstack_depth_to_print = val;
319         return 0;
320 }
321 early_param("kstack", kstack_setup);
322
323 static int __init code_bytes_setup(char *s)
324 {
325         ssize_t ret;
326         unsigned long val;
327
328         if (!s)
329                 return -EINVAL;
330
331         ret = kstrtoul(s, 0, &val);
332         if (ret)
333                 return ret;
334
335         code_bytes = val;
336         if (code_bytes > 8192)
337                 code_bytes = 8192;
338
339         return 1;
340 }
341 __setup("code_bytes=", code_bytes_setup);