stacktrace.c (9fe64e15148d1ff81fa0bcb5fd58531e3ae2aa3a) stacktrace.c (af085d9084b48530153f51e6cad19fd0b1a13ed7)
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/sched/debug.h>
8#include <linux/sched/task_stack.h>

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71 return;
72
73 __save_stack_trace(trace, tsk, NULL, true);
74
75 put_task_stack(tsk);
76}
77EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
78
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/sched/debug.h>
8#include <linux/sched/task_stack.h>

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71 return;
72
73 __save_stack_trace(trace, tsk, NULL, true);
74
75 put_task_stack(tsk);
76}
77EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
78
79#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
80
81#define STACKTRACE_DUMP_ONCE(task) ({ \
82 static bool __section(.data.unlikely) __dumped; \
83 \
84 if (!__dumped) { \
85 __dumped = true; \
86 WARN_ON(1); \
87 show_stack(task, NULL); \
88 } \
89})
90
91static int __save_stack_trace_reliable(struct stack_trace *trace,
92 struct task_struct *task)
93{
94 struct unwind_state state;
95 struct pt_regs *regs;
96 unsigned long addr;
97
98 for (unwind_start(&state, task, NULL, NULL); !unwind_done(&state);
99 unwind_next_frame(&state)) {
100
101 regs = unwind_get_entry_regs(&state);
102 if (regs) {
103 /*
104 * Kernel mode registers on the stack indicate an
105 * in-kernel interrupt or exception (e.g., preemption
106 * or a page fault), which can make frame pointers
107 * unreliable.
108 */
109 if (!user_mode(regs))
110 return -EINVAL;
111
112 /*
113 * The last frame contains the user mode syscall
114 * pt_regs. Skip it and finish the unwind.
115 */
116 unwind_next_frame(&state);
117 if (!unwind_done(&state)) {
118 STACKTRACE_DUMP_ONCE(task);
119 return -EINVAL;
120 }
121 break;
122 }
123
124 addr = unwind_get_return_address(&state);
125
126 /*
127 * A NULL or invalid return address probably means there's some
128 * generated code which __kernel_text_address() doesn't know
129 * about.
130 */
131 if (!addr) {
132 STACKTRACE_DUMP_ONCE(task);
133 return -EINVAL;
134 }
135
136 if (save_stack_address(trace, addr, false))
137 return -EINVAL;
138 }
139
140 /* Check for stack corruption */
141 if (unwind_error(&state)) {
142 STACKTRACE_DUMP_ONCE(task);
143 return -EINVAL;
144 }
145
146 if (trace->nr_entries < trace->max_entries)
147 trace->entries[trace->nr_entries++] = ULONG_MAX;
148
149 return 0;
150}
151
152/*
153 * This function returns an error if it detects any unreliable features of the
154 * stack. Otherwise it guarantees that the stack trace is reliable.
155 *
156 * If the task is not 'current', the caller *must* ensure the task is inactive.
157 */
158int save_stack_trace_tsk_reliable(struct task_struct *tsk,
159 struct stack_trace *trace)
160{
161 int ret;
162
163 if (!try_get_task_stack(tsk))
164 return -EINVAL;
165
166 ret = __save_stack_trace_reliable(trace, tsk);
167
168 put_task_stack(tsk);
169
170 return ret;
171}
172#endif /* CONFIG_HAVE_RELIABLE_STACKTRACE */
173
79/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
80
81struct stack_frame_user {
82 const void __user *next_fp;
83 unsigned long ret_addr;
84};
85
86static int

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133 * Trace user stack if we are not a kernel thread
134 */
135 if (current->mm) {
136 __save_stack_trace_user(trace);
137 }
138 if (trace->nr_entries < trace->max_entries)
139 trace->entries[trace->nr_entries++] = ULONG_MAX;
140}
174/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
175
176struct stack_frame_user {
177 const void __user *next_fp;
178 unsigned long ret_addr;
179};
180
181static int

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228 * Trace user stack if we are not a kernel thread
229 */
230 if (current->mm) {
231 __save_stack_trace_user(trace);
232 }
233 if (trace->nr_entries < trace->max_entries)
234 trace->entries[trace->nr_entries++] = ULONG_MAX;
235}
141