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>
20 #define N_EXCEPTION_STACKS_END \
21 (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
23 static char x86_stack_ids
[][8] = {
24 [ DEBUG_STACK
-1 ] = "#DB",
25 [ NMI_STACK
-1 ] = "NMI",
26 [ DOUBLEFAULT_STACK
-1 ] = "#DF",
27 [ STACKFAULT_STACK
-1 ] = "#SS",
28 [ MCE_STACK
-1 ] = "#MC",
29 #if DEBUG_STKSZ > EXCEPTION_STKSZ
30 [ N_EXCEPTION_STACKS
...
31 N_EXCEPTION_STACKS_END
] = "#DB[?]"
35 static unsigned long *in_exception_stack(unsigned cpu
, unsigned long stack
,
36 unsigned *usedp
, char **idp
)
41 * Iterate over all exception stacks, and figure out whether
42 * 'stack' is in one of them:
44 for (k
= 0; k
< N_EXCEPTION_STACKS
; k
++) {
45 unsigned long end
= per_cpu(orig_ist
, cpu
).ist
[k
];
47 * Is 'stack' above this exception frame's end?
48 * If yes then skip to the next frame.
53 * Is 'stack' above this exception frame's start address?
54 * If yes then we found the right frame.
56 if (stack
>= end
- EXCEPTION_STKSZ
) {
58 * Make sure we only iterate through an exception
59 * stack once. If it comes up for the second time
60 * then there's something wrong going on - just
61 * break out and return NULL:
63 if (*usedp
& (1U << k
))
66 *idp
= x86_stack_ids
[k
];
67 return (unsigned long *)end
;
70 * If this is a debug stack, and if it has a larger size than
71 * the usual exception stacks, then 'stack' might still
72 * be within the lower portion of the debug stack:
74 #if DEBUG_STKSZ > EXCEPTION_STKSZ
75 if (k
== DEBUG_STACK
- 1 && stack
>= end
- DEBUG_STKSZ
) {
76 unsigned j
= N_EXCEPTION_STACKS
- 1;
79 * Black magic. A large debug stack is composed of
80 * multiple exception stack entries, which we
81 * iterate through now. Dont look:
85 end
-= EXCEPTION_STKSZ
;
86 x86_stack_ids
[j
][4] = '1' +
87 (j
- N_EXCEPTION_STACKS
);
88 } while (stack
< end
- EXCEPTION_STKSZ
);
89 if (*usedp
& (1U << j
))
92 *idp
= x86_stack_ids
[j
];
93 return (unsigned long *)end
;
101 in_irq_stack(unsigned long *stack
, unsigned long *irq_stack
,
102 unsigned long *irq_stack_end
)
104 return (stack
>= irq_stack
&& stack
< irq_stack_end
);
107 static const unsigned long irq_stack_size
=
108 (IRQ_STACK_SIZE
- 64) / sizeof(unsigned long);
117 static enum stack_type
118 analyze_stack(int cpu
, struct task_struct
*task
,
119 unsigned long *stack
, unsigned long **stack_end
, char **id
)
121 unsigned long *irq_stack
;
125 addr
= ((unsigned long)stack
& (~(THREAD_SIZE
- 1)));
126 if ((unsigned long)task_stack_page(task
) == addr
)
127 return STACK_IS_NORMAL
;
129 *stack_end
= in_exception_stack(cpu
, (unsigned long)stack
,
132 return STACK_IS_EXCEPTION
;
134 *stack_end
= (unsigned long *)per_cpu(irq_stack_ptr
, cpu
);
136 return STACK_IS_UNKNOWN
;
138 irq_stack
= *stack_end
- irq_stack_size
;
140 if (in_irq_stack(stack
, irq_stack
, *stack_end
))
143 return STACK_IS_UNKNOWN
;
147 * x86-64 can have up to three kernel stacks:
150 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
153 void dump_trace(struct task_struct
*task
, struct pt_regs
*regs
,
154 unsigned long *stack
, unsigned long bp
,
155 const struct stacktrace_ops
*ops
, void *data
)
157 const unsigned cpu
= get_cpu();
158 struct thread_info
*tinfo
;
159 unsigned long *irq_stack
;
169 stack
= (unsigned long *)regs
->sp
;
170 else if (task
!= current
)
171 stack
= (unsigned long *)task
->thread
.sp
;
177 bp
= stack_frame(task
, regs
);
179 * Print function call entries in all stacks, starting at the
180 * current stack address. If the stacks consist of nested
183 tinfo
= task_thread_info(task
);
185 unsigned long *stack_end
;
186 enum stack_type stype
;
189 stype
= analyze_stack(cpu
, task
, stack
, &stack_end
, &id
);
191 /* Default finish unless specified to continue */
196 /* Break out early if we are on the thread stack */
197 case STACK_IS_NORMAL
:
200 case STACK_IS_EXCEPTION
:
202 if (ops
->stack(data
, id
) < 0)
205 bp
= ops
->walk_stack(tinfo
, stack
, bp
, ops
,
206 data
, stack_end
, &graph
);
207 ops
->stack(data
, "<EOE>");
209 * We link to the next stack via the
210 * second-to-last pointer (index -2 to end) in the
213 stack
= (unsigned long *) stack_end
[-2];
219 if (ops
->stack(data
, "IRQ") < 0)
221 bp
= ops
->walk_stack(tinfo
, stack
, bp
,
222 ops
, data
, stack_end
, &graph
);
224 * We link to the next stack (which would be
225 * the process stack normally) the last
226 * pointer (index -1 to end) in the IRQ stack:
228 stack
= (unsigned long *) (stack_end
[-1]);
229 irq_stack
= stack_end
- irq_stack_size
;
230 ops
->stack(data
, "EOI");
234 case STACK_IS_UNKNOWN
:
235 ops
->stack(data
, "UNK");
241 * This handles the process stack:
243 bp
= ops
->walk_stack(tinfo
, stack
, bp
, ops
, data
, NULL
, &graph
);
246 EXPORT_SYMBOL(dump_trace
);
249 show_stack_log_lvl(struct task_struct
*task
, struct pt_regs
*regs
,
250 unsigned long *sp
, unsigned long bp
, char *log_lvl
)
252 unsigned long *irq_stack_end
;
253 unsigned long *irq_stack
;
254 unsigned long *stack
;
259 cpu
= smp_processor_id();
261 irq_stack_end
= (unsigned long *)(per_cpu(irq_stack_ptr
, cpu
));
262 irq_stack
= (unsigned long *)(per_cpu(irq_stack_ptr
, cpu
) - IRQ_STACK_SIZE
);
265 * Debugging aid: "show_stack(NULL, NULL);" prints the
266 * back trace for this cpu:
270 sp
= (unsigned long *)task
->thread
.sp
;
272 sp
= (unsigned long *)&sp
;
276 for (i
= 0; i
< kstack_depth_to_print
; i
++) {
277 if (stack
>= irq_stack
&& stack
<= irq_stack_end
) {
278 if (stack
== irq_stack_end
) {
279 stack
= (unsigned long *) (irq_stack_end
[-1]);
283 if (((long) stack
& (THREAD_SIZE
-1)) == 0)
286 if (i
&& ((i
% STACKSLOTS_PER_LINE
) == 0))
288 pr_cont(" %016lx", *stack
++);
289 touch_nmi_watchdog();
294 show_trace_log_lvl(task
, regs
, sp
, bp
, log_lvl
);
297 void show_regs(struct pt_regs
*regs
)
303 show_regs_print_info(KERN_DEFAULT
);
304 __show_regs(regs
, 1);
307 * When in-kernel, we also print out the stack and code at the
308 * time of the fault..
310 if (!user_mode(regs
)) {
311 unsigned int code_prologue
= code_bytes
* 43 / 64;
312 unsigned int code_len
= code_bytes
;
316 printk(KERN_DEFAULT
"Stack:\n");
317 show_stack_log_lvl(NULL
, regs
, (unsigned long *)sp
,
320 printk(KERN_DEFAULT
"Code: ");
322 ip
= (u8
*)regs
->ip
- code_prologue
;
323 if (ip
< (u8
*)PAGE_OFFSET
|| probe_kernel_address(ip
, c
)) {
324 /* try starting at IP */
326 code_len
= code_len
- code_prologue
+ 1;
328 for (i
= 0; i
< code_len
; i
++, ip
++) {
329 if (ip
< (u8
*)PAGE_OFFSET
||
330 probe_kernel_address(ip
, c
)) {
331 pr_cont(" Bad RIP value.");
334 if (ip
== (u8
*)regs
->ip
)
335 pr_cont("<%02x> ", c
);
343 int is_valid_bugaddr(unsigned long ip
)
347 if (__copy_from_user(&ud2
, (const void __user
*) ip
, sizeof(ud2
)))
350 return ud2
== 0x0b0f;
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