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1/*
2 * Stack trace management functions
3 *
4 * Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
5 */
6#include <linux/sched.h>
7#include <linux/stacktrace.h>
8#include <linux/export.h>
9#include <linux/uaccess.h>
10#include <asm/stacktrace.h>
11#include <asm/unwind.h>
12
13static int save_stack_address(struct stack_trace *trace, unsigned long addr,
14 bool nosched)
15{
16 if (nosched && in_sched_functions(addr))
17 return 0;
18
19 if (trace->skip > 0) {
20 trace->skip--;
21 return 0;
22 }
23
24 if (trace->nr_entries >= trace->max_entries)
25 return -1;
26
27 trace->entries[trace->nr_entries++] = addr;
28 return 0;
29}
30
31static void __save_stack_trace(struct stack_trace *trace,
32 struct task_struct *task, struct pt_regs *regs,
33 bool nosched)
34{
35 struct unwind_state state;
36 unsigned long addr;
37
38 if (regs)
39 save_stack_address(trace, regs->ip, nosched);
40
41 for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
42 unwind_next_frame(&state)) {
43 addr = unwind_get_return_address(&state);
44 if (!addr || save_stack_address(trace, addr, nosched))
45 break;
46 }
47
48 if (trace->nr_entries < trace->max_entries)
49 trace->entries[trace->nr_entries++] = ULONG_MAX;
50}
51
52/*
53 * Save stack-backtrace addresses into a stack_trace buffer.
54 */
55void save_stack_trace(struct stack_trace *trace)
56{
57 __save_stack_trace(trace, current, NULL, false);
58}
59EXPORT_SYMBOL_GPL(save_stack_trace);
60
61void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
62{
63 __save_stack_trace(trace, current, regs, false);
64}
65
66void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
67{
68 if (!try_get_task_stack(tsk))
69 return;
70
71 __save_stack_trace(trace, tsk, NULL, true);
72
73 put_task_stack(tsk);
74}
75EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
76
77/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
78
79struct stack_frame_user {
80 const void __user *next_fp;
81 unsigned long ret_addr;
82};
83
84static int
85copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
86{
87 int ret;
88
89 if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
90 return 0;
91
92 ret = 1;
93 pagefault_disable();
94 if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
95 ret = 0;
96 pagefault_enable();
97
98 return ret;
99}
100
101static inline void __save_stack_trace_user(struct stack_trace *trace)
102{
103 const struct pt_regs *regs = task_pt_regs(current);
104 const void __user *fp = (const void __user *)regs->bp;
105
106 if (trace->nr_entries < trace->max_entries)
107 trace->entries[trace->nr_entries++] = regs->ip;
108
109 while (trace->nr_entries < trace->max_entries) {
110 struct stack_frame_user frame;
111
112 frame.next_fp = NULL;
113 frame.ret_addr = 0;
114 if (!copy_stack_frame(fp, &frame))
115 break;
116 if ((unsigned long)fp < regs->sp)
117 break;
118 if (frame.ret_addr) {
119 trace->entries[trace->nr_entries++] =
120 frame.ret_addr;
121 }
122 if (fp == frame.next_fp)
123 break;
124 fp = frame.next_fp;
125 }
126}
127
128void save_stack_trace_user(struct stack_trace *trace)
129{
130 /*
131 * Trace user stack if we are not a kernel thread
132 */
133 if (current->mm) {
134 __save_stack_trace_user(trace);
135 }
136 if (trace->nr_entries < trace->max_entries)
137 trace->entries[trace->nr_entries++] = ULONG_MAX;
138}
139
1/*
2 * Stack trace management functions
3 *
4 * Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
5 */
6#include <linux/sched.h>
7#include <linux/stacktrace.h>
8#include <linux/module.h>
9#include <linux/uaccess.h>
10#include <asm/stacktrace.h>
11
12static int save_stack_stack(void *data, char *name)
13{
14 return 0;
15}
16
17static int
18__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
19{
20 struct stack_trace *trace = data;
21#ifdef CONFIG_FRAME_POINTER
22 if (!reliable)
23 return 0;
24#endif
25 if (nosched && in_sched_functions(addr))
26 return 0;
27 if (trace->skip > 0) {
28 trace->skip--;
29 return 0;
30 }
31 if (trace->nr_entries < trace->max_entries) {
32 trace->entries[trace->nr_entries++] = addr;
33 return 0;
34 } else {
35 return -1; /* no more room, stop walking the stack */
36 }
37}
38
39static int save_stack_address(void *data, unsigned long addr, int reliable)
40{
41 return __save_stack_address(data, addr, reliable, false);
42}
43
44static int
45save_stack_address_nosched(void *data, unsigned long addr, int reliable)
46{
47 return __save_stack_address(data, addr, reliable, true);
48}
49
50static const struct stacktrace_ops save_stack_ops = {
51 .stack = save_stack_stack,
52 .address = save_stack_address,
53 .walk_stack = print_context_stack,
54};
55
56static const struct stacktrace_ops save_stack_ops_nosched = {
57 .stack = save_stack_stack,
58 .address = save_stack_address_nosched,
59 .walk_stack = print_context_stack,
60};
61
62/*
63 * Save stack-backtrace addresses into a stack_trace buffer.
64 */
65void save_stack_trace(struct stack_trace *trace)
66{
67 dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
68 if (trace->nr_entries < trace->max_entries)
69 trace->entries[trace->nr_entries++] = ULONG_MAX;
70}
71EXPORT_SYMBOL_GPL(save_stack_trace);
72
73void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
74{
75 dump_trace(current, regs, NULL, 0, &save_stack_ops, trace);
76 if (trace->nr_entries < trace->max_entries)
77 trace->entries[trace->nr_entries++] = ULONG_MAX;
78}
79
80void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
81{
82 dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
83 if (trace->nr_entries < trace->max_entries)
84 trace->entries[trace->nr_entries++] = ULONG_MAX;
85}
86EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
87
88/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
89
90struct stack_frame_user {
91 const void __user *next_fp;
92 unsigned long ret_addr;
93};
94
95static int
96copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
97{
98 int ret;
99
100 if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
101 return 0;
102
103 ret = 1;
104 pagefault_disable();
105 if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
106 ret = 0;
107 pagefault_enable();
108
109 return ret;
110}
111
112static inline void __save_stack_trace_user(struct stack_trace *trace)
113{
114 const struct pt_regs *regs = task_pt_regs(current);
115 const void __user *fp = (const void __user *)regs->bp;
116
117 if (trace->nr_entries < trace->max_entries)
118 trace->entries[trace->nr_entries++] = regs->ip;
119
120 while (trace->nr_entries < trace->max_entries) {
121 struct stack_frame_user frame;
122
123 frame.next_fp = NULL;
124 frame.ret_addr = 0;
125 if (!copy_stack_frame(fp, &frame))
126 break;
127 if ((unsigned long)fp < regs->sp)
128 break;
129 if (frame.ret_addr) {
130 trace->entries[trace->nr_entries++] =
131 frame.ret_addr;
132 }
133 if (fp == frame.next_fp)
134 break;
135 fp = frame.next_fp;
136 }
137}
138
139void save_stack_trace_user(struct stack_trace *trace)
140{
141 /*
142 * Trace user stack if we are not a kernel thread
143 */
144 if (current->mm) {
145 __save_stack_trace_user(trace);
146 }
147 if (trace->nr_entries < trace->max_entries)
148 trace->entries[trace->nr_entries++] = ULONG_MAX;
149}
150