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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "base/debug/stack_trace.h" | 5 #include "base/debug/stack_trace.h" |
6 | 6 |
7 #include <string.h> | 7 #include <string.h> |
8 | 8 |
9 #include <algorithm> | 9 #include <algorithm> |
10 #include <limits> | |
11 #include <sstream> | 10 #include <sstream> |
12 | 11 |
13 #include "base/macros.h" | 12 #include "base/macros.h" |
14 | 13 |
15 #if HAVE_TRACE_STACK_FRAME_POINTERS | 14 #if HAVE_TRACE_STACK_FRAME_POINTERS |
16 | 15 |
17 #if defined(OS_LINUX) || defined(OS_ANDROID) | 16 #if defined(OS_LINUX) || defined(OS_ANDROID) |
18 #include <pthread.h> | 17 #include <pthread.h> |
19 #include "base/process/process_handle.h" | 18 #include "base/process/process_handle.h" |
20 #include "base/threading/platform_thread.h" | 19 #include "base/threading/platform_thread.h" |
21 #endif | 20 #endif |
22 | 21 |
23 #if defined(OS_LINUX) && defined(__GLIBC__) | 22 #if defined(OS_LINUX) && defined(__GLIBC__) |
24 extern "C" void* __libc_stack_end; | 23 extern "C" void* __libc_stack_end; |
25 #endif | 24 #endif |
26 | 25 |
27 #endif // HAVE_TRACE_STACK_FRAME_POINTERS | 26 #endif // HAVE_TRACE_STACK_FRAME_POINTERS |
28 | 27 |
29 namespace base { | 28 namespace base { |
30 namespace debug { | 29 namespace debug { |
31 | 30 |
32 StackTrace::StackTrace(const void* const* trace, size_t count) { | 31 namespace { |
33 count = std::min(count, arraysize(trace_)); | |
34 if (count) | |
35 memcpy(trace_, trace, count * sizeof(trace_[0])); | |
36 count_ = count; | |
37 } | |
38 | |
39 StackTrace::~StackTrace() { | |
40 } | |
41 | |
42 const void *const *StackTrace::Addresses(size_t* count) const { | |
43 *count = count_; | |
44 if (count_) | |
45 return trace_; | |
46 return NULL; | |
47 } | |
48 | |
49 std::string StackTrace::ToString() const { | |
50 std::stringstream stream; | |
51 #if !defined(__UCLIBC__) | |
52 OutputToStream(&stream); | |
53 #endif | |
54 return stream.str(); | |
55 } | |
56 | 32 |
57 #if HAVE_TRACE_STACK_FRAME_POINTERS | 33 #if HAVE_TRACE_STACK_FRAME_POINTERS |
58 | 34 |
59 static uintptr_t GetStackEnd() { | 35 #if defined(OS_LINUX) |
36 #define SCAN_STACK_FOR_FRAMES | |
37 // TraceStackFramePointers() will try to scan stack for frame pointers to | |
38 // continue unwinding past system libraries. Only supported on Linux where | |
39 // system libraries are usually in the middle of the trace, for example: | |
40 // | |
41 // TraceStackFramePointers | |
42 // <more frames from Chrome> | |
43 // g_main_context_dispatch <--- unwinding stops here | |
44 // g_main_context_iteration | |
45 // base::MessagePumpGlib::Run | |
46 // base::RunLoop::Run <--- resumes from here | |
47 // <more frames from Chrome> | |
48 // __libc_start_main | |
49 // | |
50 // Note that base::MessagePumpGlib::Run() is lost, because its frame was | |
51 // not saved by g_main_context_iteration(). | |
52 // | |
53 // For stack scanning to be efficient it's very important for the thread to | |
54 // be started by Chrome. In that case we naturally terminate unwinding once | |
55 // we reach the origin of the stack (i.e. GetStackEnd()). If the thread was | |
56 // not started by Chrome (e.g. Android's main thread), then we end up always | |
57 // scanning area at the origin of the stack, wasting time and not finding any | |
58 // frames (since e.g. Android libraries don't have frame pointers). | |
59 | |
60 // Allows to resume ~95% of all prematurely terminated traces on Linux. | |
61 constexpr size_t kMaxStackScanArea = 512; | |
62 #endif | |
63 | |
64 // Returns end of the stack, or 0 if it's unknown. | |
65 uintptr_t GetStackEnd() { | |
60 #if defined(OS_ANDROID) | 66 #if defined(OS_ANDROID) |
61 // Bionic reads proc/maps on every call to pthread_getattr_np() when called | 67 // Bionic reads proc/maps on every call to pthread_getattr_np() when called |
62 // from the main thread. So we need to cache end of stack in that case to get | 68 // from the main thread. So we need to cache end of stack in that case to get |
63 // acceptable performance. | 69 // acceptable performance. |
64 // For all other threads pthread_getattr_np() is fast enough as it just reads | 70 // For all other threads pthread_getattr_np() is fast enough as it just reads |
65 // values from its pthread_t argument. | 71 // values from its pthread_t argument. |
66 static uintptr_t main_stack_end = 0; | 72 static uintptr_t main_stack_end = 0; |
67 | 73 |
68 bool is_main_thread = GetCurrentProcId() == PlatformThread::CurrentId(); | 74 bool is_main_thread = GetCurrentProcId() == PlatformThread::CurrentId(); |
69 if (is_main_thread && main_stack_end) { | 75 if (is_main_thread && main_stack_end) { |
(...skipping 20 matching lines...) Expand all Loading... | |
90 return stack_end; | 96 return stack_end; |
91 | 97 |
92 #elif defined(OS_LINUX) && defined(__GLIBC__) | 98 #elif defined(OS_LINUX) && defined(__GLIBC__) |
93 | 99 |
94 if (GetCurrentProcId() == PlatformThread::CurrentId()) { | 100 if (GetCurrentProcId() == PlatformThread::CurrentId()) { |
95 // For the main thread we have a shortcut. | 101 // For the main thread we have a shortcut. |
96 return reinterpret_cast<uintptr_t>(__libc_stack_end); | 102 return reinterpret_cast<uintptr_t>(__libc_stack_end); |
97 } else { | 103 } else { |
98 // No easy way to get stack end for non-main threads, | 104 // No easy way to get stack end for non-main threads, |
99 // see crbug.com/617730. | 105 // see crbug.com/617730. |
100 return std::numeric_limits<uintptr_t>::max(); | 106 return 0; |
101 } | 107 } |
102 | 108 |
103 #else | 109 #else |
104 | 110 |
105 // TODO(dskiba): support Windows, macOS | 111 // TODO(dskiba): support Windows, macOS |
106 return std::numeric_limits<uintptr_t>::max(); | 112 return 0; |
107 | 113 |
108 #endif | 114 #endif |
109 } | 115 } |
110 | 116 |
117 #if defined(__arm__) && defined(__GNUC__) && !defined(__clang__) | |
118 // GCC and LLVM generate slightly different frames on ARM, see | |
119 // https://llvm.org/bugs/show_bug.cgi?id=18505 - LLVM generates | |
120 // x86-compatible frame, while GCC needs adjustment. | |
121 constexpr size_t kStackFrameAdjustment = sizeof(uintptr_t); | |
122 #else | |
123 constexpr size_t kStackFrameAdjustment = 0; | |
124 #endif | |
125 | |
126 uintptr_t GetNextStackFrame(uintptr_t fp) { | |
127 return reinterpret_cast<const uintptr_t*>(fp)[0] - kStackFrameAdjustment; | |
128 } | |
129 | |
130 uintptr_t GetStackFramePC(uintptr_t fp) { | |
131 return reinterpret_cast<const uintptr_t*>(fp)[1]; | |
132 } | |
133 | |
134 bool IsStackFrameValid(uintptr_t fp, uintptr_t prev_fp, uintptr_t stack_end) { | |
135 // With the stack growing downwards, older stack frame must be | |
136 // at a greater address that the current one. | |
137 if (fp <= prev_fp) return false; | |
138 | |
139 // Assume huge stack frames are bogus. | |
140 if (fp - prev_fp > 100000) return false; | |
141 | |
142 // Check alignment. | |
143 if (fp & (sizeof(uintptr_t) - 1)) return false; | |
144 | |
145 if (stack_end) { | |
146 // Both fp[0] and fp[1] must be within the stack. | |
147 if (fp > stack_end - 2 * sizeof(uintptr_t)) return false; | |
148 | |
149 #if defined(SCAN_STACK_FOR_FRAMES) | |
150 // Additional check to filter out false positives. | |
151 if (GetStackFramePC(fp) < 32768) return false; | |
152 #endif | |
153 } | |
154 | |
155 return true; | |
156 }; | |
157 | |
158 #endif // HAVE_TRACE_STACK_FRAME_POINTERS | |
159 | |
160 } // namespace | |
161 | |
162 StackTrace::StackTrace(const void* const* trace, size_t count) { | |
163 count = std::min(count, arraysize(trace_)); | |
164 if (count) | |
165 memcpy(trace_, trace, count * sizeof(trace_[0])); | |
166 count_ = count; | |
167 } | |
168 | |
169 StackTrace::~StackTrace() { | |
170 } | |
171 | |
172 const void *const *StackTrace::Addresses(size_t* count) const { | |
173 *count = count_; | |
174 if (count_) | |
175 return trace_; | |
176 return NULL; | |
177 } | |
178 | |
179 std::string StackTrace::ToString() const { | |
180 std::stringstream stream; | |
181 #if !defined(__UCLIBC__) | |
182 OutputToStream(&stream); | |
183 #endif | |
184 return stream.str(); | |
185 } | |
186 | |
187 #if HAVE_TRACE_STACK_FRAME_POINTERS | |
188 | |
111 size_t TraceStackFramePointers(const void** out_trace, | 189 size_t TraceStackFramePointers(const void** out_trace, |
112 size_t max_depth, | 190 size_t max_depth, |
113 size_t skip_initial) { | 191 size_t skip_initial) { |
114 // Usage of __builtin_frame_address() enables frame pointers in this | 192 // Usage of __builtin_frame_address() enables frame pointers in this |
115 // function even if they are not enabled globally. So 'sp' will always | 193 // function even if they are not enabled globally. So 'fp' will always |
116 // be valid. | 194 // be valid. |
117 uintptr_t sp = reinterpret_cast<uintptr_t>(__builtin_frame_address(0)); | 195 uintptr_t fp = reinterpret_cast<uintptr_t>(__builtin_frame_address(0)) - |
196 kStackFrameAdjustment; | |
118 | 197 |
119 uintptr_t stack_end = GetStackEnd(); | 198 uintptr_t stack_end = GetStackEnd(); |
120 | 199 |
121 size_t depth = 0; | 200 size_t depth = 0; |
122 while (depth < max_depth) { | 201 while (depth < max_depth) { |
123 #if defined(__arm__) && defined(__GNUC__) && !defined(__clang__) | |
124 // GCC and LLVM generate slightly different frames on ARM, see | |
125 // https://llvm.org/bugs/show_bug.cgi?id=18505 - LLVM generates | |
126 // x86-compatible frame, while GCC needs adjustment. | |
127 sp -= sizeof(uintptr_t); | |
128 #endif | |
129 | |
130 // Both sp[0] and s[1] must be valid. | |
131 if (sp + 2 * sizeof(uintptr_t) > stack_end) { | |
132 break; | |
133 } | |
134 | |
135 if (skip_initial != 0) { | 202 if (skip_initial != 0) { |
136 skip_initial--; | 203 skip_initial--; |
137 } else { | 204 } else { |
138 out_trace[depth++] = reinterpret_cast<const void**>(sp)[1]; | 205 out_trace[depth++] = reinterpret_cast<const void*>(GetStackFramePC(fp)); |
139 } | 206 } |
140 | 207 |
141 // Find out next frame pointer | 208 uintptr_t next_fp = GetNextStackFrame(fp); |
142 // (heuristics are from TCMalloc's stacktrace functions) | 209 if (!IsStackFrameValid(next_fp, fp, stack_end)) { |
Primiano Tucci (use gerrit)
2016/08/25 11:42:53
I'd reverse the if condition and reduce one leven
Dmitry Skiba
2016/08/30 18:04:21
Done.
| |
143 { | 210 #if defined(SCAN_STACK_FOR_FRAMES) |
Primiano Tucci (use gerrit)
2016/08/25 11:42:53
Since you introduced all these beautiful helper fu
Dmitry Skiba
2016/08/30 18:04:21
Done.
Primiano Tucci (use gerrit)
2016/08/31 13:48:49
Doesn't seem so :)
WHat I mean is for ScanStackFor
Dmitry Skiba
2016/09/07 22:33:24
Ah, I see. Done now :)
| |
144 uintptr_t next_sp = reinterpret_cast<const uintptr_t*>(sp)[0]; | 211 if (!stack_end) { |
145 | 212 break; |
146 // With the stack growing downwards, older stack frame must be | 213 } |
147 // at a greater address that the current one. | 214 fp += sizeof(uintptr_t); |
148 if (next_sp <= sp) break; | 215 uintptr_t last_scan_fp = std::min(fp + kMaxStackScanArea, stack_end) - |
Primiano Tucci (use gerrit)
2016/08/25 11:42:53
Just a minor naming thing: when I saw "last_scan_f
Dmitry Skiba
2016/08/30 18:04:21
Done.
| |
149 | 216 sizeof(uintptr_t); |
150 // Assume stack frames larger than 100,000 bytes are bogus. | 217 for (;fp <= last_scan_fp; fp += sizeof(uintptr_t)) { |
151 if (next_sp - sp > 100000) break; | 218 next_fp = GetNextStackFrame(fp); |
152 | 219 if (IsStackFrameValid(next_fp, fp, stack_end)) { |
153 // Check alignment. | 220 // Check two frames deep. Since stack frame is just a pointer to |
154 if (sp & (sizeof(void*) - 1)) break; | 221 // a higher address on the stack, it's relatively easy to find |
155 | 222 // something that looks like one. However two linked frames are |
156 sp = next_sp; | 223 // far less likely to be bogus. |
224 uintptr_t next2_fp = GetNextStackFrame(next_fp); | |
Primiano Tucci (use gerrit)
2016/08/25 11:42:53
Hmm I'm missing something here, does this mean tha
Dmitry Skiba
2016/08/30 18:04:21
This tries to get rid of false positives - it's fa
| |
225 if (IsStackFrameValid(next2_fp, next_fp, stack_end)) { | |
226 break; | |
227 } | |
228 } | |
229 } | |
230 if (fp > last_scan_fp) { | |
231 break; | |
232 } | |
157 } | 233 } |
234 fp = next_fp; | |
235 #else | |
236 // Stack scanning is not enabled, stop unwinding. | |
237 break; | |
238 #endif // defined(SCAN_STACK_FOR_FRAMES) | |
158 } | 239 } |
159 | 240 |
160 return depth; | 241 return depth; |
161 } | 242 } |
162 | 243 |
163 #endif // HAVE_TRACE_STACK_FRAME_POINTERS | 244 #endif // HAVE_TRACE_STACK_FRAME_POINTERS |
164 | 245 |
165 } // namespace debug | 246 } // namespace debug |
166 } // namespace base | 247 } // namespace base |
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