asan_stack.cc revision cb8c4dce691097718d5af41b36899b72ef4b1d84
1//===-- asan_stack.cc -----------------------------------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file is a part of AddressSanitizer, an address sanity checker. 11// 12// Code for ASan stack trace. 13//===----------------------------------------------------------------------===// 14#include "asan_interceptors.h" 15#include "asan_lock.h" 16#include "asan_stack.h" 17#include "asan_thread.h" 18#include "asan_thread_registry.h" 19#include "sanitizer_common/sanitizer_procmaps.h" 20#include "sanitizer_common/sanitizer_symbolizer.h" 21 22#ifdef ASAN_USE_EXTERNAL_SYMBOLIZER 23extern bool 24ASAN_USE_EXTERNAL_SYMBOLIZER(const void *pc, char *out, int out_size); 25#endif 26 27namespace __asan { 28 29// ----------------------- AsanStackTrace ----------------------------- {{{1 30#if defined(ASAN_USE_EXTERNAL_SYMBOLIZER) 31void AsanStackTrace::PrintStack(uptr *addr, uptr size) { 32 for (uptr i = 0; i < size && addr[i]; i++) { 33 uptr pc = addr[i]; 34 char buff[4096]; 35 ASAN_USE_EXTERNAL_SYMBOLIZER((void*)pc, buff, sizeof(buff)); 36 AsanPrintf(" #%zu 0x%zx %s\n", i, pc, buff); 37 } 38} 39 40#else // ASAN_USE_EXTERNAL_SYMBOLIZER 41void AsanStackTrace::PrintStack(uptr *addr, uptr size) { 42 ProcessMaps proc_maps; 43 uptr frame_num = 0; 44 for (uptr i = 0; i < size && addr[i]; i++) { 45 uptr pc = addr[i]; 46 AddressInfo addr_frames[64]; 47 uptr addr_frames_num = 0; 48 if (flags()->symbolize) { 49 bool last_frame = (i == size - 1) || !addr[i + 1]; 50 addr_frames_num = SymbolizeCode(pc - !last_frame, addr_frames, 51 ASAN_ARRAY_SIZE(addr_frames)); 52 } 53 if (addr_frames_num > 0) { 54 for (uptr j = 0; j < addr_frames_num; j++) { 55 AddressInfo &info = addr_frames[j]; 56 AsanPrintf(" #%zu 0x%zx", frame_num, pc); 57 if (info.function) { 58 AsanPrintf(" in %s", info.function); 59 } 60 if (info.file) { 61 AsanPrintf(" %s:%d:%d", info.file, info.line, info.column); 62 } else if (info.module) { 63 AsanPrintf(" (%s+0x%zx)", info.module, info.module_offset); 64 } 65 AsanPrintf("\n"); 66 info.Clear(); 67 frame_num++; 68 } 69 } else { 70 uptr offset; 71 char filename[4096]; 72 if (proc_maps.GetObjectNameAndOffset(pc, &offset, 73 filename, sizeof(filename))) { 74 AsanPrintf(" #%zu 0x%zx (%s+0x%zx)\n", frame_num, pc, filename, 75 offset); 76 } else { 77 AsanPrintf(" #%zu 0x%zx\n", frame_num, pc); 78 } 79 frame_num++; 80 } 81 } 82} 83#endif // ASAN_USE_EXTERNAL_SYMBOLIZER 84 85uptr AsanStackTrace::GetCurrentPc() { 86 return GET_CALLER_PC(); 87} 88 89void AsanStackTrace::FastUnwindStack(uptr pc, uptr bp) { 90 CHECK(size == 0 && trace[0] == pc); 91 size = 1; 92 if (!asan_inited) return; 93 AsanThread *t = asanThreadRegistry().GetCurrent(); 94 if (!t) return; 95 uptr *frame = (uptr*)bp; 96 uptr *prev_frame = frame; 97 uptr *top = (uptr*)t->stack_top(); 98 uptr *bottom = (uptr*)t->stack_bottom(); 99 while (frame >= prev_frame && 100 frame < top - 2 && 101 frame > bottom && 102 size < max_size) { 103 uptr pc1 = frame[1]; 104 if (pc1 != pc) { 105 trace[size++] = pc1; 106 } 107 prev_frame = frame; 108 frame = (uptr*)frame[0]; 109 } 110} 111 112// On 32-bits we don't compress stack traces. 113// On 64-bits we compress stack traces: if a given pc differes slightly from 114// the previous one, we record a 31-bit offset instead of the full pc. 115uptr AsanStackTrace::CompressStack(AsanStackTrace *stack, 116 u32 *compressed, uptr size) { 117#if __WORDSIZE == 32 118 // Don't compress, just copy. 119 uptr res = 0; 120 for (uptr i = 0; i < stack->size && i < size; i++) { 121 compressed[i] = stack->trace[i]; 122 res++; 123 } 124 if (stack->size < size) 125 compressed[stack->size] = 0; 126#else // 64 bits, compress. 127 uptr prev_pc = 0; 128 const uptr kMaxOffset = (1ULL << 30) - 1; 129 uptr c_index = 0; 130 uptr res = 0; 131 for (uptr i = 0, n = stack->size; i < n; i++) { 132 uptr pc = stack->trace[i]; 133 if (!pc) break; 134 if ((s64)pc < 0) break; 135 // Printf("C pc[%zu] %zx\n", i, pc); 136 if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) { 137 uptr offset = (s64)(pc - prev_pc); 138 offset |= (1U << 31); 139 if (c_index >= size) break; 140 // Printf("C co[%zu] offset %zx\n", i, offset); 141 compressed[c_index++] = offset; 142 } else { 143 uptr hi = pc >> 32; 144 uptr lo = (pc << 32) >> 32; 145 CHECK((hi & (1 << 31)) == 0); 146 if (c_index + 1 >= size) break; 147 // Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo); 148 compressed[c_index++] = hi; 149 compressed[c_index++] = lo; 150 } 151 res++; 152 prev_pc = pc; 153 } 154 if (c_index < size) 155 compressed[c_index] = 0; 156 if (c_index + 1 < size) 157 compressed[c_index + 1] = 0; 158#endif // __WORDSIZE 159 160 // debug-only code 161#if 0 162 AsanStackTrace check_stack; 163 UncompressStack(&check_stack, compressed, size); 164 if (res < check_stack.size) { 165 Printf("res %zu check_stack.size %zu; c_size %zu\n", res, 166 check_stack.size, size); 167 } 168 // |res| may be greater than check_stack.size, because 169 // UncompressStack(CompressStack(stack)) eliminates the 0x0 frames. 170 CHECK(res >= check_stack.size); 171 CHECK(0 == REAL(memcmp)(check_stack.trace, stack->trace, 172 check_stack.size * sizeof(uptr))); 173#endif 174 175 return res; 176} 177 178void AsanStackTrace::UncompressStack(AsanStackTrace *stack, 179 u32 *compressed, uptr size) { 180#if __WORDSIZE == 32 181 // Don't uncompress, just copy. 182 stack->size = 0; 183 for (uptr i = 0; i < size && i < kStackTraceMax; i++) { 184 if (!compressed[i]) break; 185 stack->size++; 186 stack->trace[i] = compressed[i]; 187 } 188#else // 64 bits, uncompress 189 uptr prev_pc = 0; 190 stack->size = 0; 191 for (uptr i = 0; i < size && stack->size < kStackTraceMax; i++) { 192 u32 x = compressed[i]; 193 uptr pc = 0; 194 if (x & (1U << 31)) { 195 // Printf("U co[%zu] offset: %x\n", i, x); 196 // this is an offset 197 s32 offset = x; 198 offset = (offset << 1) >> 1; // remove the 31-byte and sign-extend. 199 pc = prev_pc + offset; 200 CHECK(pc); 201 } else { 202 // CHECK(i + 1 < size); 203 if (i + 1 >= size) break; 204 uptr hi = x; 205 uptr lo = compressed[i+1]; 206 // Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo); 207 i++; 208 pc = (hi << 32) | lo; 209 if (!pc) break; 210 } 211 // Printf("U pc[%zu] %zx\n", stack->size, pc); 212 stack->trace[stack->size++] = pc; 213 prev_pc = pc; 214 } 215#endif // __WORDSIZE 216} 217 218} // namespace __asan 219