aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/stacktrace.c
blob: dd55312f3fe9c6f42dfe3e43151830675804f96e (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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
/*
 * kernel/stacktrace.c
 *
 * Stack trace management functions
 *
 *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 */
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>

/**
 * stack_trace_print - Print the entries in the stack trace
 * @entries:	Pointer to storage array
 * @nr_entries:	Number of entries in the storage array
 * @spaces:	Number of leading spaces to print
 */
void stack_trace_print(unsigned long *entries, unsigned int nr_entries,
		       int spaces)
{
	unsigned int i;

	if (WARN_ON(!entries))
		return;

	for (i = 0; i < nr_entries; i++)
		printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
}
EXPORT_SYMBOL_GPL(stack_trace_print);

/**
 * stack_trace_snprint - Print the entries in the stack trace into a buffer
 * @buf:	Pointer to the print buffer
 * @size:	Size of the print buffer
 * @entries:	Pointer to storage array
 * @nr_entries:	Number of entries in the storage array
 * @spaces:	Number of leading spaces to print
 *
 * Return: Number of bytes printed.
 */
int stack_trace_snprint(char *buf, size_t size, unsigned long *entries,
			unsigned int nr_entries, int spaces)
{
	unsigned int generated, i, total = 0;

	if (WARN_ON(!entries))
		return 0;

	for (i = 0; i < nr_entries && size; i++) {
		generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
				     (void *)entries[i]);

		total += generated;
		if (generated >= size) {
			buf += size;
			size = 0;
		} else {
			buf += generated;
			size -= generated;
		}
	}

	return total;
}
EXPORT_SYMBOL_GPL(stack_trace_snprint);

/*
 * Architectures that do not implement save_stack_trace_*()
 * get these weak aliases and once-per-bootup warnings
 * (whenever this facility is utilized - for example by procfs):
 */
__weak void
save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
	WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
}

__weak void
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
	WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
}

__weak int
save_stack_trace_tsk_reliable(struct task_struct *tsk,
			      struct stack_trace *trace)
{
	WARN_ONCE(1, KERN_INFO "save_stack_tsk_reliable() not implemented yet.\n");
	return -ENOSYS;
}

/**
 * stack_trace_save - Save a stack trace into a storage array
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
			      unsigned int skipnr)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
		.skip		= skipnr + 1,
	};

	save_stack_trace(&trace);
	return trace.nr_entries;
}
EXPORT_SYMBOL_GPL(stack_trace_save);

/**
 * stack_trace_save_tsk - Save a task stack trace into a storage array
 * @task:	The task to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save_tsk(struct task_struct *task,
				  unsigned long *store, unsigned int size,
				  unsigned int skipnr)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
		.skip		= skipnr + 1,
	};

	save_stack_trace_tsk(task, &trace);
	return trace.nr_entries;
}

/**
 * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
 * @regs:	Pointer to pt_regs to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
				   unsigned int size, unsigned int skipnr)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
		.skip		= skipnr,
	};

	save_stack_trace_regs(regs, &trace);
	return trace.nr_entries;
}

#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
/**
 * stack_trace_save_tsk_reliable - Save task stack with verification
 * @tsk:	Pointer to the task to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 *
 * Return:	An error if it detects any unreliable features of the
 *		stack. Otherwise it guarantees that the stack trace is
 *		reliable and returns the number of entries stored.
 *
 * If the task is not 'current', the caller *must* ensure the task is inactive.
 */
int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
				  unsigned int size)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
	};
	int ret = save_stack_trace_tsk_reliable(tsk, &trace);

	return ret ? ret : trace.nr_entries;
}
#endif

#ifdef CONFIG_USER_STACKTRACE_SUPPORT
/**
 * stack_trace_save_user - Save a user space stack trace into a storage array
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
	};

	save_stack_trace_user(&trace);
	return trace.nr_entries;
}
#endif /* CONFIG_USER_STACKTRACE_SUPPORT */

Privacy Policy