2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
5 #include <linux/kallsyms.h>
6 #include <linux/kprobes.h>
7 #include <linux/uaccess.h>
8 #include <linux/hardirq.h>
9 #include <linux/kdebug.h>
10 #include <linux/module.h>
11 #include <linux/ptrace.h>
12 #include <linux/kexec.h>
13 #include <linux/sysfs.h>
14 #include <linux/bug.h>
15 #include <linux/nmi.h>
17 #include <asm/stacktrace.h>
19 #include "dumpstack.h"
21 #define N_EXCEPTION_STACKS_END \
22 (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
24 static char x86_stack_ids
[][8] = {
25 [ DEBUG_STACK
-1 ] = "#DB",
26 [ NMI_STACK
-1 ] = "NMI",
27 [ DOUBLEFAULT_STACK
-1 ] = "#DF",
28 [ STACKFAULT_STACK
-1 ] = "#SS",
29 [ MCE_STACK
-1 ] = "#MC",
30 #if DEBUG_STKSZ > EXCEPTION_STKSZ
31 [ N_EXCEPTION_STACKS
...
32 N_EXCEPTION_STACKS_END
] = "#DB[?]"
36 static unsigned long *in_exception_stack(unsigned cpu
, unsigned long stack
,
37 unsigned *usedp
, char **idp
)
42 * Iterate over all exception stacks, and figure out whether
43 * 'stack' is in one of them:
45 for (k
= 0; k
< N_EXCEPTION_STACKS
; k
++) {
46 unsigned long end
= per_cpu(orig_ist
, cpu
).ist
[k
];
48 * Is 'stack' above this exception frame's end?
49 * If yes then skip to the next frame.
54 * Is 'stack' above this exception frame's start address?
55 * If yes then we found the right frame.
57 if (stack
>= end
- EXCEPTION_STKSZ
) {
59 * Make sure we only iterate through an exception
60 * stack once. If it comes up for the second time
61 * then there's something wrong going on - just
62 * break out and return NULL:
64 if (*usedp
& (1U << k
))
67 *idp
= x86_stack_ids
[k
];
68 return (unsigned long *)end
;
71 * If this is a debug stack, and if it has a larger size than
72 * the usual exception stacks, then 'stack' might still
73 * be within the lower portion of the debug stack:
75 #if DEBUG_STKSZ > EXCEPTION_STKSZ
76 if (k
== DEBUG_STACK
- 1 && stack
>= end
- DEBUG_STKSZ
) {
77 unsigned j
= N_EXCEPTION_STACKS
- 1;
80 * Black magic. A large debug stack is composed of
81 * multiple exception stack entries, which we
82 * iterate through now. Dont look:
86 end
-= EXCEPTION_STKSZ
;
87 x86_stack_ids
[j
][4] = '1' +
88 (j
- N_EXCEPTION_STACKS
);
89 } while (stack
< end
- EXCEPTION_STKSZ
);
90 if (*usedp
& (1U << j
))
93 *idp
= x86_stack_ids
[j
];
94 return (unsigned long *)end
;
102 in_irq_stack(unsigned long *stack
, unsigned long *irq_stack
,
103 unsigned long *irq_stack_end
)
105 return (stack
>= irq_stack
&& stack
< irq_stack_end
);
109 * We are returning from the irq stack and go to the previous one.
110 * If the previous stack is also in the irq stack, then bp in the first
111 * frame of the irq stack points to the previous, interrupted one.
112 * Otherwise we have another level of indirection: We first save
113 * the bp of the previous stack, then we switch the stack to the irq one
114 * and save a new bp that links to the previous one.
117 static inline unsigned long
118 fixup_bp_irq_link(unsigned long bp
, unsigned long *stack
,
119 unsigned long *irq_stack
, unsigned long *irq_stack_end
)
121 #ifdef CONFIG_FRAME_POINTER
122 struct stack_frame
*frame
= (struct stack_frame
*)bp
;
125 if (!in_irq_stack(stack
, irq_stack
, irq_stack_end
)) {
126 if (!probe_kernel_address(&frame
->next_frame
, next
))
129 WARN_ONCE(1, "Perf: bad frame pointer = %p in "
130 "callchain\n", &frame
->next_frame
);
137 * x86-64 can have up to three kernel stacks:
140 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
143 void dump_trace(struct task_struct
*task
, struct pt_regs
*regs
,
144 unsigned long *stack
, unsigned long bp
,
145 const struct stacktrace_ops
*ops
, void *data
)
147 const unsigned cpu
= get_cpu();
148 unsigned long *irq_stack_end
=
149 (unsigned long *)per_cpu(irq_stack_ptr
, cpu
);
151 struct thread_info
*tinfo
;
160 if (task
&& task
!= current
)
161 stack
= (unsigned long *)task
->thread
.sp
;
164 #ifdef CONFIG_FRAME_POINTER
166 if (task
== current
) {
167 /* Grab bp right from our regs */
170 /* bp is the last reg pushed by switch_to */
171 bp
= *(unsigned long *) task
->thread
.sp
;
177 * Print function call entries in all stacks, starting at the
178 * current stack address. If the stacks consist of nested
181 tinfo
= task_thread_info(task
);
184 unsigned long *estack_end
;
185 estack_end
= in_exception_stack(cpu
, (unsigned long)stack
,
189 if (ops
->stack(data
, id
) < 0)
192 bp
= ops
->walk_stack(tinfo
, stack
, bp
, ops
,
193 data
, estack_end
, &graph
);
194 ops
->stack(data
, "<EOE>");
196 * We link to the next stack via the
197 * second-to-last pointer (index -2 to end) in the
200 stack
= (unsigned long *) estack_end
[-2];
204 unsigned long *irq_stack
;
205 irq_stack
= irq_stack_end
-
206 (IRQ_STACK_SIZE
- 64) / sizeof(*irq_stack
);
208 if (in_irq_stack(stack
, irq_stack
, irq_stack_end
)) {
209 if (ops
->stack(data
, "IRQ") < 0)
211 bp
= ops
->walk_stack(tinfo
, stack
, bp
,
212 ops
, data
, irq_stack_end
, &graph
);
214 * We link to the next stack (which would be
215 * the process stack normally) the last
216 * pointer (index -1 to end) in the IRQ stack:
218 stack
= (unsigned long *) (irq_stack_end
[-1]);
219 bp
= fixup_bp_irq_link(bp
, stack
, irq_stack
,
221 irq_stack_end
= NULL
;
222 ops
->stack(data
, "EOI");
230 * This handles the process stack:
232 bp
= ops
->walk_stack(tinfo
, stack
, bp
, ops
, data
, NULL
, &graph
);
235 EXPORT_SYMBOL(dump_trace
);
238 show_stack_log_lvl(struct task_struct
*task
, struct pt_regs
*regs
,
239 unsigned long *sp
, unsigned long bp
, char *log_lvl
)
241 unsigned long *irq_stack_end
;
242 unsigned long *irq_stack
;
243 unsigned long *stack
;
248 cpu
= smp_processor_id();
250 irq_stack_end
= (unsigned long *)(per_cpu(irq_stack_ptr
, cpu
));
251 irq_stack
= (unsigned long *)(per_cpu(irq_stack_ptr
, cpu
) - IRQ_STACK_SIZE
);
254 * Debugging aid: "show_stack(NULL, NULL);" prints the
255 * back trace for this cpu:
259 sp
= (unsigned long *)task
->thread
.sp
;
261 sp
= (unsigned long *)&sp
;
265 for (i
= 0; i
< kstack_depth_to_print
; i
++) {
266 if (stack
>= irq_stack
&& stack
<= irq_stack_end
) {
267 if (stack
== irq_stack_end
) {
268 stack
= (unsigned long *) (irq_stack_end
[-1]);
272 if (((long) stack
& (THREAD_SIZE
-1)) == 0)
275 if (i
&& ((i
% STACKSLOTS_PER_LINE
) == 0))
276 printk("\n%s", log_lvl
);
277 printk(" %016lx", *stack
++);
278 touch_nmi_watchdog();
283 show_trace_log_lvl(task
, regs
, sp
, bp
, log_lvl
);
286 void show_registers(struct pt_regs
*regs
)
290 const int cpu
= smp_processor_id();
291 struct task_struct
*cur
= current
;
294 printk("CPU %d ", cpu
);
296 __show_regs(regs
, 1);
297 printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
298 cur
->comm
, cur
->pid
, task_thread_info(cur
), cur
);
301 * When in-kernel, we also print out the stack and code at the
302 * time of the fault..
304 if (!user_mode(regs
)) {
305 unsigned int code_prologue
= code_bytes
* 43 / 64;
306 unsigned int code_len
= code_bytes
;
310 printk(KERN_EMERG
"Stack:\n");
311 show_stack_log_lvl(NULL
, regs
, (unsigned long *)sp
,
312 regs
->bp
, KERN_EMERG
);
314 printk(KERN_EMERG
"Code: ");
316 ip
= (u8
*)regs
->ip
- code_prologue
;
317 if (ip
< (u8
*)PAGE_OFFSET
|| probe_kernel_address(ip
, c
)) {
318 /* try starting at IP */
320 code_len
= code_len
- code_prologue
+ 1;
322 for (i
= 0; i
< code_len
; i
++, ip
++) {
323 if (ip
< (u8
*)PAGE_OFFSET
||
324 probe_kernel_address(ip
, c
)) {
325 printk(" Bad RIP value.");
328 if (ip
== (u8
*)regs
->ip
)
329 printk("<%02x> ", c
);
337 int is_valid_bugaddr(unsigned long ip
)
341 if (__copy_from_user(&ud2
, (const void __user
*) ip
, sizeof(ud2
)))
344 return ud2
== 0x0b0f;
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