1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2008 ARM Limited
* Copyright (C) 2014 Regents of the University of California
*/
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/stacktrace.h>
#include <linux/ftrace.h>
#ifdef CONFIG_FRAME_POINTER
struct stackframe {
unsigned long fp;
unsigned long ra;
};
void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
bool (*fn)(unsigned long, void *), void *arg)
{
unsigned long fp, sp, pc;
if (regs) {
fp = frame_pointer(regs);
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
const register unsigned long current_sp __asm__ ("sp");
fp = (unsigned long)__builtin_frame_address(0);
sp = current_sp;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */
fp = task->thread.s[0];
sp = task->thread.sp;
pc = task->thread.ra;
}
for (;;) {
unsigned long low, high;
struct stackframe *frame;
if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
break;
/* Validate frame pointer */
low = sp + sizeof(struct stackframe);
high = ALIGN(sp, THREAD_SIZE);
if (unlikely(fp < low || fp > high || fp & 0x7))
break;
/* Unwind stack frame */
frame = (struct stackframe *)fp - 1;
sp = fp;
fp = frame->fp;
pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
(unsigned long *)(fp - 8));
}
}
#else /* !CONFIG_FRAME_POINTER */
static void notrace walk_stackframe(struct task_struct *task,
struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
{
unsigned long sp, pc;
unsigned long *ksp;
if (regs) {
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
const register unsigned long current_sp __asm__ ("sp");
sp = current_sp;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */
sp = task->thread.sp;
pc = task->thread.ra;
}
if (unlikely(sp & 0x7))
return;
ksp = (unsigned long *)sp;
while (!kstack_end(ksp)) {
if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
break;
pc = (*ksp++) - 0x4;
}
}
#endif /* CONFIG_FRAME_POINTER */
static bool print_trace_address(unsigned long pc, void *arg)
{
print_ip_sym(pc);
return false;
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
pr_cont("Call Trace:\n");
walk_stackframe(task, NULL, print_trace_address, NULL);
}
static bool save_wchan(unsigned long pc, void *arg)
{
if (!in_sched_functions(pc)) {
unsigned long *p = arg;
*p = pc;
return true;
}
return false;
}
unsigned long get_wchan(struct task_struct *task)
{
unsigned long pc = 0;
if (likely(task && task != current && task->state != TASK_RUNNING))
walk_stackframe(task, NULL, save_wchan, &pc);
return pc;
}
#ifdef CONFIG_STACKTRACE
static bool __save_trace(unsigned long pc, void *arg, bool nosched)
{
struct stack_trace *trace = arg;
if (unlikely(nosched && in_sched_functions(pc)))
return false;
if (unlikely(trace->skip > 0)) {
trace->skip--;
return false;
}
trace->entries[trace->nr_entries++] = pc;
return (trace->nr_entries >= trace->max_entries);
}
static bool save_trace(unsigned long pc, void *arg)
{
return __save_trace(pc, arg, false);
}
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
walk_stackframe(tsk, NULL, save_trace, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
void save_stack_trace(struct stack_trace *trace)
{
save_stack_trace_tsk(NULL, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace);
#endif /* CONFIG_STACKTRACE */
|
