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Commit | Line | Data |
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21b32bbf | 1 | /* |
21b32bbf IM |
2 | * Stack trace management functions |
3 | * | |
8f47e163 | 4 | * Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
21b32bbf IM |
5 | */ |
6 | #include <linux/sched.h> | |
b17b0153 | 7 | #include <linux/sched/debug.h> |
21b32bbf | 8 | #include <linux/stacktrace.h> |
186f4360 | 9 | #include <linux/export.h> |
02b67518 | 10 | #include <linux/uaccess.h> |
c0b766f1 | 11 | #include <asm/stacktrace.h> |
49a612c6 | 12 | #include <asm/unwind.h> |
21b32bbf | 13 | |
49a612c6 JP |
14 | static int save_stack_address(struct stack_trace *trace, unsigned long addr, |
15 | bool nosched) | |
21b32bbf | 16 | { |
018378c5 | 17 | if (nosched && in_sched_functions(addr)) |
568b329a | 18 | return 0; |
49a612c6 | 19 | |
c0b766f1 AK |
20 | if (trace->skip > 0) { |
21 | trace->skip--; | |
568b329a | 22 | return 0; |
21b32bbf | 23 | } |
21b32bbf | 24 | |
49a612c6 JP |
25 | if (trace->nr_entries >= trace->max_entries) |
26 | return -1; | |
27 | ||
28 | trace->entries[trace->nr_entries++] = addr; | |
29 | return 0; | |
018378c5 ON |
30 | } |
31 | ||
49a612c6 JP |
32 | static void __save_stack_trace(struct stack_trace *trace, |
33 | struct task_struct *task, struct pt_regs *regs, | |
34 | bool nosched) | |
9745512c | 35 | { |
49a612c6 JP |
36 | struct unwind_state state; |
37 | unsigned long addr; | |
9745512c | 38 | |
49a612c6 JP |
39 | if (regs) |
40 | save_stack_address(trace, regs->ip, nosched); | |
21b32bbf | 41 | |
49a612c6 JP |
42 | for (unwind_start(&state, task, regs, NULL); !unwind_done(&state); |
43 | unwind_next_frame(&state)) { | |
44 | addr = unwind_get_return_address(&state); | |
45 | if (!addr || save_stack_address(trace, addr, nosched)) | |
46 | break; | |
47 | } | |
48 | ||
49 | if (trace->nr_entries < trace->max_entries) | |
50 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
51 | } | |
9745512c | 52 | |
21b32bbf IM |
53 | /* |
54 | * Save stack-backtrace addresses into a stack_trace buffer. | |
21b32bbf | 55 | */ |
ab1b6f03 | 56 | void save_stack_trace(struct stack_trace *trace) |
21b32bbf | 57 | { |
49a612c6 | 58 | __save_stack_trace(trace, current, NULL, false); |
21b32bbf | 59 | } |
8594698e | 60 | EXPORT_SYMBOL_GPL(save_stack_trace); |
9745512c | 61 | |
39581062 | 62 | void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) |
acc6be54 | 63 | { |
49a612c6 | 64 | __save_stack_trace(trace, current, regs, false); |
acc6be54 VN |
65 | } |
66 | ||
9745512c AV |
67 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) |
68 | { | |
1959a601 AL |
69 | if (!try_get_task_stack(tsk)) |
70 | return; | |
71 | ||
49a612c6 | 72 | __save_stack_trace(trace, tsk, NULL, true); |
1959a601 AL |
73 | |
74 | put_task_stack(tsk); | |
9745512c | 75 | } |
8594698e | 76 | EXPORT_SYMBOL_GPL(save_stack_trace_tsk); |
02b67518 TE |
77 | |
78 | /* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */ | |
79 | ||
c9cf4dbb | 80 | struct stack_frame_user { |
02b67518 | 81 | const void __user *next_fp; |
8d7c6a96 | 82 | unsigned long ret_addr; |
02b67518 TE |
83 | }; |
84 | ||
c9cf4dbb FW |
85 | static int |
86 | copy_stack_frame(const void __user *fp, struct stack_frame_user *frame) | |
02b67518 TE |
87 | { |
88 | int ret; | |
89 | ||
90 | if (!access_ok(VERIFY_READ, fp, sizeof(*frame))) | |
91 | return 0; | |
92 | ||
93 | ret = 1; | |
94 | pagefault_disable(); | |
95 | if (__copy_from_user_inatomic(frame, fp, sizeof(*frame))) | |
96 | ret = 0; | |
97 | pagefault_enable(); | |
98 | ||
99 | return ret; | |
100 | } | |
101 | ||
8d7c6a96 TE |
102 | static inline void __save_stack_trace_user(struct stack_trace *trace) |
103 | { | |
104 | const struct pt_regs *regs = task_pt_regs(current); | |
105 | const void __user *fp = (const void __user *)regs->bp; | |
106 | ||
107 | if (trace->nr_entries < trace->max_entries) | |
108 | trace->entries[trace->nr_entries++] = regs->ip; | |
109 | ||
110 | while (trace->nr_entries < trace->max_entries) { | |
c9cf4dbb | 111 | struct stack_frame_user frame; |
8d7c6a96 TE |
112 | |
113 | frame.next_fp = NULL; | |
114 | frame.ret_addr = 0; | |
115 | if (!copy_stack_frame(fp, &frame)) | |
116 | break; | |
117 | if ((unsigned long)fp < regs->sp) | |
118 | break; | |
119 | if (frame.ret_addr) { | |
120 | trace->entries[trace->nr_entries++] = | |
121 | frame.ret_addr; | |
122 | } | |
123 | if (fp == frame.next_fp) | |
124 | break; | |
125 | fp = frame.next_fp; | |
126 | } | |
127 | } | |
128 | ||
02b67518 TE |
129 | void save_stack_trace_user(struct stack_trace *trace) |
130 | { | |
131 | /* | |
132 | * Trace user stack if we are not a kernel thread | |
133 | */ | |
134 | if (current->mm) { | |
8d7c6a96 | 135 | __save_stack_trace_user(trace); |
02b67518 TE |
136 | } |
137 | if (trace->nr_entries < trace->max_entries) | |
138 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
139 | } | |
140 |