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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 // TraceStackFramePointers() will try to scan stack for frame pointers to | |
37 // continue unwinding past system libraries. Only supported on Linux where | |
38 // system libraries are usually in the middle of the trace, for example: | |
39 // | |
40 // TraceStackFramePointers | |
41 // <more frames from Chrome> | |
42 // g_main_context_dispatch <--- unwinding stops here | |
43 // g_main_context_iteration | |
44 // base::MessagePumpGlib::Run | |
45 // base::RunLoop::Run <--- resumes from here | |
46 // <more frames from Chrome> | |
47 // __libc_start_main | |
48 // | |
49 // Note that base::MessagePumpGlib::Run() is lost, because its frame was | |
50 // not saved by g_main_context_iteration(). | |
51 // | |
52 // For stack scanning to be efficient it's very important for the thread to | |
53 // be started by Chrome. In that case we naturally terminate unwinding once | |
54 // we reach the origin of the stack (i.e. GetStackEnd()). If the thread was | |
55 // not started by Chrome (e.g. Android's main thread), then we end up always | |
56 // scanning area at the origin of the stack, wasting time and not finding any | |
57 // frames (since e.g. Android libraries don't have frame pointers). | |
58 #define SCAN_STACK_FOR_FRAMES | |
59 | |
60 // Allows to resume ~95% of all prematurely terminated traces on Linux. | |
61 constexpr size_t kMaxStackScanArea = 512; | |
62 #endif | |
63 | |
64 #if defined(__arm__) && defined(__GNUC__) && !defined(__clang__) | |
65 // GCC and LLVM generate slightly different frames on ARM, see | |
66 // https://llvm.org/bugs/show_bug.cgi?id=18505 - LLVM generates | |
67 // x86-compatible frame, while GCC needs adjustment. | |
68 constexpr size_t kStackFrameAdjustment = sizeof(uintptr_t); | |
69 #else | |
70 constexpr size_t kStackFrameAdjustment = 0; | |
71 #endif | |
72 | |
73 // Returns end of the stack, or 0 if we couldn't get it. | |
74 uintptr_t GetStackEnd() { | |
60 #if defined(OS_ANDROID) | 75 #if defined(OS_ANDROID) |
61 // Bionic reads proc/maps on every call to pthread_getattr_np() when called | 76 // 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 | 77 // from the main thread. So we need to cache end of stack in that case to get |
63 // acceptable performance. | 78 // acceptable performance. |
64 // For all other threads pthread_getattr_np() is fast enough as it just reads | 79 // For all other threads pthread_getattr_np() is fast enough as it just reads |
65 // values from its pthread_t argument. | 80 // values from its pthread_t argument. |
66 static uintptr_t main_stack_end = 0; | 81 static uintptr_t main_stack_end = 0; |
67 | 82 |
68 bool is_main_thread = GetCurrentProcId() == PlatformThread::CurrentId(); | 83 bool is_main_thread = GetCurrentProcId() == PlatformThread::CurrentId(); |
69 if (is_main_thread && main_stack_end) { | 84 if (is_main_thread && main_stack_end) { |
(...skipping 10 matching lines...) Expand all Loading... | |
80 reinterpret_cast<void**>(&stack_begin), | 95 reinterpret_cast<void**>(&stack_begin), |
81 &stack_size); | 96 &stack_size); |
82 pthread_attr_destroy(&attributes); | 97 pthread_attr_destroy(&attributes); |
83 } | 98 } |
84 DCHECK(!error); | 99 DCHECK(!error); |
85 | 100 |
86 uintptr_t stack_end = stack_begin + stack_size; | 101 uintptr_t stack_end = stack_begin + stack_size; |
87 if (is_main_thread) { | 102 if (is_main_thread) { |
88 main_stack_end = stack_end; | 103 main_stack_end = stack_end; |
89 } | 104 } |
90 return stack_end; | 105 return stack_end; // 0 in case of error |
91 | 106 |
92 #elif defined(OS_LINUX) && defined(__GLIBC__) | 107 #elif defined(OS_LINUX) && defined(__GLIBC__) |
93 | 108 |
94 if (GetCurrentProcId() == PlatformThread::CurrentId()) { | 109 if (GetCurrentProcId() == PlatformThread::CurrentId()) { |
95 // For the main thread we have a shortcut. | 110 // For the main thread we have a shortcut. |
96 return reinterpret_cast<uintptr_t>(__libc_stack_end); | 111 return reinterpret_cast<uintptr_t>(__libc_stack_end); |
97 } | 112 } |
98 | 113 |
99 // No easy way to get stack end for non-main threads, see crbug.com/617730. | 114 // No easy way to get end of the stack for non-main threads, |
100 | 115 // see crbug.com/617730. |
101 #else | |
102 | |
103 // TODO(dskiba): support Windows, macOS | |
104 | 116 |
105 #endif | 117 #endif |
106 | 118 |
107 // Couldn't get end of stack address. | 119 // Don't know how to get end of the stack. |
108 return std::numeric_limits<uintptr_t>::max(); | 120 return 0; |
109 } | 121 } |
110 | 122 |
123 uintptr_t GetNextStackFrame(uintptr_t fp) { | |
124 return reinterpret_cast<const uintptr_t*>(fp)[0] - kStackFrameAdjustment; | |
125 } | |
126 | |
127 uintptr_t GetStackFramePC(uintptr_t fp) { | |
128 return reinterpret_cast<const uintptr_t*>(fp)[1]; | |
129 } | |
130 | |
131 bool IsStackFrameValid(uintptr_t fp, uintptr_t prev_fp, uintptr_t stack_end) { | |
132 // With the stack growing downwards, older stack frame must be | |
133 // at a greater address that the current one. | |
134 if (fp <= prev_fp) return false; | |
135 | |
136 // Assume huge stack frames are bogus. | |
137 if (fp - prev_fp > 100000) return false; | |
138 | |
139 // Check alignment. | |
140 if (fp & (sizeof(uintptr_t) - 1)) return false; | |
141 | |
142 if (stack_end) { | |
143 // Both fp[0] and fp[1] must be within the stack. | |
144 if (fp > stack_end - 2 * sizeof(uintptr_t)) return false; | |
145 | |
146 #if defined(SCAN_STACK_FOR_FRAMES) | |
Primiano Tucci (use gerrit)
2016/08/31 13:48:50
why this extra check is if-defed? makes sense in a
| |
147 // Additional check to filter out false positives. | |
148 if (GetStackFramePC(fp) < 32768) return false; | |
149 #endif | |
150 } | |
151 | |
152 return true; | |
153 }; | |
154 | |
155 #if defined(SCAN_STACK_FOR_FRAMES) | |
156 | |
157 // Returns 0 on failure. | |
158 uintptr_t ScanStackForNextFrame(uintptr_t fp, uintptr_t stack_end) { | |
159 if (!stack_end) { | |
160 // Too dangerous to scan without knowing where the stack ends. | |
161 return 0; | |
162 } | |
163 | |
164 fp += sizeof(uintptr_t); // current frame is known to be invalid | |
165 uintptr_t last_fp_to_scan = std::min(fp + kMaxStackScanArea, stack_end) - | |
166 sizeof(uintptr_t); | |
167 for (;fp <= last_fp_to_scan; fp += sizeof(uintptr_t)) { | |
168 uintptr_t next_fp = GetNextStackFrame(fp); | |
169 if (IsStackFrameValid(next_fp, fp, stack_end)) { | |
Primiano Tucci (use gerrit)
2016/08/31 13:48:50
Ahhh now I understand what this really does.
For a
| |
170 // Check two frames deep. Since stack frame is just a pointer to | |
171 // a higher address on the stack, it's relatively easy to find | |
172 // something that looks like one. However two linked frames are | |
173 // far less likely to be bogus. | |
174 uintptr_t next2_fp = GetNextStackFrame(next_fp); | |
175 if (IsStackFrameValid(next2_fp, next_fp, stack_end)) { | |
176 return fp; | |
177 } | |
178 } | |
179 } | |
180 | |
181 return 0; | |
182 } | |
183 | |
184 #endif // defined(SCAN_STACK_FOR_FRAMES) | |
185 | |
186 #endif // HAVE_TRACE_STACK_FRAME_POINTERS | |
187 | |
188 } // namespace | |
189 | |
190 StackTrace::StackTrace(const void* const* trace, size_t count) { | |
191 count = std::min(count, arraysize(trace_)); | |
192 if (count) | |
193 memcpy(trace_, trace, count * sizeof(trace_[0])); | |
194 count_ = count; | |
195 } | |
196 | |
197 StackTrace::~StackTrace() { | |
Primiano Tucci (use gerrit)
2016/08/31 13:48:50
nit: I think this should be {} (without the newlin
| |
198 } | |
199 | |
200 const void *const *StackTrace::Addresses(size_t* count) const { | |
201 *count = count_; | |
202 if (count_) | |
203 return trace_; | |
204 return NULL; | |
205 } | |
206 | |
207 std::string StackTrace::ToString() const { | |
208 std::stringstream stream; | |
209 #if !defined(__UCLIBC__) | |
210 OutputToStream(&stream); | |
211 #endif | |
212 return stream.str(); | |
213 } | |
214 | |
215 #if HAVE_TRACE_STACK_FRAME_POINTERS | |
216 | |
111 size_t TraceStackFramePointers(const void** out_trace, | 217 size_t TraceStackFramePointers(const void** out_trace, |
112 size_t max_depth, | 218 size_t max_depth, |
113 size_t skip_initial) { | 219 size_t skip_initial) { |
114 // Usage of __builtin_frame_address() enables frame pointers in this | 220 // Usage of __builtin_frame_address() enables frame pointers in this |
115 // function even if they are not enabled globally. So 'sp' will always | 221 // function even if they are not enabled globally. So 'fp' will always |
116 // be valid. | 222 // be valid. |
117 uintptr_t sp = reinterpret_cast<uintptr_t>(__builtin_frame_address(0)); | 223 uintptr_t fp = reinterpret_cast<uintptr_t>(__builtin_frame_address(0)) - |
224 kStackFrameAdjustment; | |
118 | 225 |
119 uintptr_t stack_end = GetStackEnd(); | 226 uintptr_t stack_end = GetStackEnd(); |
120 | 227 |
121 size_t depth = 0; | 228 size_t depth = 0; |
122 while (depth < max_depth) { | 229 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) { | 230 if (skip_initial != 0) { |
136 skip_initial--; | 231 skip_initial--; |
137 } else { | 232 } else { |
138 out_trace[depth++] = reinterpret_cast<const void**>(sp)[1]; | 233 out_trace[depth++] = reinterpret_cast<const void*>(GetStackFramePC(fp)); |
Primiano Tucci (use gerrit)
2016/08/31 13:48:50
I think you just lost the protection for the first
Dmitry Skiba
2016/09/07 22:33:24
Actually, __builtin_frame_address() will force fra
| |
139 } | 234 } |
140 | 235 |
141 // Find out next frame pointer | 236 uintptr_t next_fp = GetNextStackFrame(fp); |
142 // (heuristics are from TCMalloc's stacktrace functions) | 237 if (IsStackFrameValid(next_fp, fp, stack_end)) { |
143 { | 238 fp = next_fp; |
144 uintptr_t next_sp = reinterpret_cast<const uintptr_t*>(sp)[0]; | 239 continue; |
240 } | |
241 #if defined(SCAN_STACK_FOR_FRAMES) | |
242 next_fp = ScanStackForNextFrame(fp, stack_end); | |
243 if (next_fp) { | |
244 fp = next_fp; | |
245 continue; | |
246 } | |
247 #endif | |
145 | 248 |
146 // With the stack growing downwards, older stack frame must be | 249 // Failed to find next frame. |
147 // at a greater address that the current one. | 250 break; |
148 if (next_sp <= sp) break; | |
149 | |
150 // Assume stack frames larger than 100,000 bytes are bogus. | |
151 if (next_sp - sp > 100000) break; | |
152 | |
153 // Check alignment. | |
154 if (sp & (sizeof(void*) - 1)) break; | |
155 | |
156 sp = next_sp; | |
157 } | |
158 } | 251 } |
159 | 252 |
160 return depth; | 253 return depth; |
161 } | 254 } |
162 | 255 |
163 #endif // HAVE_TRACE_STACK_FRAME_POINTERS | 256 #endif // HAVE_TRACE_STACK_FRAME_POINTERS |
164 | 257 |
165 } // namespace debug | 258 } // namespace debug |
166 } // namespace base | 259 } // namespace base |
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