tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 void save_stack_warning(void *data, char *msg)
13{
14}
15
16static void
17save_stack_warning_symbol(void *data, char *msg, unsigned long symbol)
18{
19}
20
21static int save_stack_stack(void *data, char *name)
22{
23 return 0;
24}
25
26static void save_stack_address(void *data, unsigned long addr, int reliable)
27{
28 struct stack_trace *trace = data;
29 if (!reliable)
30 return;
31 if (trace->skip > 0) {
32 trace->skip--;
33 return;
34 }
35 if (trace->nr_entries < trace->max_entries)
36 trace->entries[trace->nr_entries++] = addr;
37}
38
39static void
40save_stack_address_nosched(void *data, unsigned long addr, int reliable)
41{
42 struct stack_trace *trace = (struct stack_trace *)data;
43 if (!reliable)
44 return;
45 if (in_sched_functions(addr))
46 return;
47 if (trace->skip > 0) {
48 trace->skip--;
49 return;
50 }
51 if (trace->nr_entries < trace->max_entries)
52 trace->entries[trace->nr_entries++] = addr;
53}
54
55static const struct stacktrace_ops save_stack_ops = {
56 .warning = save_stack_warning,
57 .warning_symbol = save_stack_warning_symbol,
58 .stack = save_stack_stack,
59 .address = save_stack_address,
60 .walk_stack = print_context_stack,
61};
62
63static const struct stacktrace_ops save_stack_ops_nosched = {
64 .warning = save_stack_warning,
65 .warning_symbol = save_stack_warning_symbol,
66 .stack = save_stack_stack,
67 .address = save_stack_address_nosched,
68 .walk_stack = print_context_stack,
69};
70
71/*
72 * Save stack-backtrace addresses into a stack_trace buffer.
73 */
74void save_stack_trace(struct stack_trace *trace)
75{
76 dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
77 if (trace->nr_entries < trace->max_entries)
78 trace->entries[trace->nr_entries++] = ULONG_MAX;
79}
80EXPORT_SYMBOL_GPL(save_stack_trace);
81
82void save_stack_trace_bp(struct stack_trace *trace, unsigned long bp)
83{
84 dump_trace(current, NULL, NULL, bp, &save_stack_ops, trace);
85 if (trace->nr_entries < trace->max_entries)
86 trace->entries[trace->nr_entries++] = ULONG_MAX;
87}
88
89void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
90{
91 dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
92 if (trace->nr_entries < trace->max_entries)
93 trace->entries[trace->nr_entries++] = ULONG_MAX;
94}
95EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
96
97/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
98
99struct stack_frame {
100 const void __user *next_fp;
101 unsigned long ret_addr;
102};
103
104static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
105{
106 int ret;
107
108 if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
109 return 0;
110
111 ret = 1;
112 pagefault_disable();
113 if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
114 ret = 0;
115 pagefault_enable();
116
117 return ret;
118}
119
120static inline void __save_stack_trace_user(struct stack_trace *trace)
121{
122 const struct pt_regs *regs = task_pt_regs(current);
123 const void __user *fp = (const void __user *)regs->bp;
124
125 if (trace->nr_entries < trace->max_entries)
126 trace->entries[trace->nr_entries++] = regs->ip;
127
128 while (trace->nr_entries < trace->max_entries) {
129 struct stack_frame frame;
130
131 frame.next_fp = NULL;
132 frame.ret_addr = 0;
133 if (!copy_stack_frame(fp, &frame))
134 break;
135 if ((unsigned long)fp < regs->sp)
136 break;
137 if (frame.ret_addr) {
138 trace->entries[trace->nr_entries++] =
139 frame.ret_addr;
140 }
141 if (fp == frame.next_fp)
142 break;
143 fp = frame.next_fp;
144 }
145}
146
147void save_stack_trace_user(struct stack_trace *trace)
148{
149 /*
150 * Trace user stack if we are not a kernel thread
151 */
152 if (current->mm) {
153 __save_stack_trace_user(trace);
154 }
155 if (trace->nr_entries < trace->max_entries)
156 trace->entries[trace->nr_entries++] = ULONG_MAX;
157}
158