aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/stacktrace.c
blob: ea54d029fe27a1175611c1150db2d961a113d29e (plain)
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
/*
 * Stack trace management functions
 *
 *  Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 */
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <asm/stacktrace.h>

static void save_stack_warning(void *data, char *msg)
{
}

static void
save_stack_warning_symbol(void *data, char *msg, unsigned long symbol)
{
}

static int save_stack_stack(void *data, char *name)
{
	return 0;
}

static void save_stack_address(void *data, unsigned long addr, int reliable)
{
	struct stack_trace *trace = data;
	if (!reliable)
		return;
	if (trace->skip > 0) {
		trace->skip--;
		return;
	}
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = addr;
}

static void
save_stack_address_nosched(void *data, unsigned long addr, int reliable)
{
	struct stack_trace *trace = (struct stack_trace *)data;
	if (!reliable)
		return;
	if (in_sched_functions(addr))
		return;
	if (trace->skip > 0) {
		trace->skip--;
		return;
	}
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = addr;
}

static const struct stacktrace_ops save_stack_ops = {
	.warning	= save_stack_warning,
	.warning_symbol	= save_stack_warning_symbol,
	.stack		= save_stack_stack,
	.address	= save_stack_address,
	.walk_stack	= print_context_stack,
};

static const struct stacktrace_ops save_stack_ops_nosched = {
	.warning	= save_stack_warning,
	.warning_symbol	= save_stack_warning_symbol,
	.stack		= save_stack_stack,
	.address	= save_stack_address_nosched,
	.walk_stack	= print_context_stack,
};

/*
 * Save stack-backtrace addresses into a stack_trace buffer.
 */
void save_stack_trace(struct stack_trace *trace)
{
	dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);

void save_stack_trace_bp(struct stack_trace *trace, unsigned long bp)
{
	dump_trace(current, NULL, NULL, bp, &save_stack_ops, trace);
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = ULONG_MAX;
}

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
	dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);

/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */

struct stack_frame_user {
	const void __user	*next_fp;
	unsigned long		ret_addr;
};

static int
copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
{
	int ret;

	if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
		return 0;

	ret = 1;
	pagefault_disable();
	if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
		ret = 0;
	pagefault_enable();

	return ret;
}

static inline void __save_stack_trace_user(struct stack_trace *trace)
{
	const struct pt_regs *regs = task_pt_regs(current);
	const void __user *fp = (const void __user *)regs->bp;

	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = regs->ip;

	while (trace->nr_entries < trace->max_entries) {
		struct stack_frame_user frame;

		frame.next_fp = NULL;
		frame.ret_addr = 0;
		if (!copy_stack_frame(fp, &frame))
			break;
		if ((unsigned long)fp < regs->sp)
			break;
		if (frame.ret_addr) {
			trace->entries[trace->nr_entries++] =
				frame.ret_addr;
		}
		if (fp == frame.next_fp)
			break;
		fp = frame.next_fp;
	}
}

void save_stack_trace_user(struct stack_trace *trace)
{
	/*
	 * Trace user stack if we are not a kernel thread
	 */
	if (current->mm) {
		__save_stack_trace_user(trace);
	}
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = ULONG_MAX;
}