asan_stack.cc revision 283c296b64bc55deec9698260b3427a9b050a925
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_interface.h" 16#include "asan_lock.h" 17#include "asan_stack.h" 18#include "asan_thread.h" 19#include "asan_thread_registry.h" 20#include "sanitizer_common/sanitizer_procmaps.h" 21#include "sanitizer_common/sanitizer_symbolizer.h" 22 23namespace __asan { 24 25static __asan_symbolize_callback symbolize_callback; 26 27static const char *StripPathPrefix(const char *filepath) { 28 const char *path_prefix = flags()->strip_path_prefix; 29 if (filepath == internal_strstr(filepath, path_prefix)) 30 return filepath + internal_strlen(path_prefix); 31 return filepath; 32} 33 34// ----------------------- AsanStackTrace ----------------------------- {{{1 35// PCs in stack traces are actually the return addresses, that is, 36// addresses of the next instructions after the call. That's why we 37// decrement them. 38static uptr patch_pc(uptr pc) { 39#ifdef __arm__ 40 // Cancel Thumb bit. 41 pc = pc & (~1); 42#endif 43 return pc - 1; 44} 45 46void AsanStackTrace::PrintStack(uptr *addr, uptr size) { 47 MemoryMappingLayout proc_maps; 48 uptr frame_num = 0; 49 for (uptr i = 0; i < size && addr[i]; i++) { 50 uptr pc = patch_pc(addr[i]); 51 if (symbolize_callback) { 52 char buff[4096]; 53 symbolize_callback((void*)pc, buff, sizeof(buff)); 54 // We can't know anything about the string returned by external 55 // symbolizer, but if it starts with filename, try to strip path prefix 56 // from it. 57 Printf(" #%zu 0x%zx %s\n", frame_num, pc, StripPathPrefix(buff)); 58 frame_num++; 59 continue; 60 } 61 AddressInfo addr_frames[64]; 62 uptr addr_frames_num = 0; 63 if (flags()->symbolize) { 64 addr_frames_num = SymbolizeCode(pc, addr_frames, 65 ASAN_ARRAY_SIZE(addr_frames)); 66 } 67 if (addr_frames_num > 0) { 68 for (uptr j = 0; j < addr_frames_num; j++) { 69 AddressInfo &info = addr_frames[j]; 70 Printf(" #%zu 0x%zx", frame_num, pc); 71 if (info.function) { 72 Printf(" in %s", info.function); 73 } 74 if (info.file) { 75 Printf(" %s:%d:%d", StripPathPrefix(info.file), info.line, 76 info.column); 77 } else if (info.module) { 78 Printf(" (%s+0x%zx)", StripPathPrefix(info.module), 79 info.module_offset); 80 } 81 Printf("\n"); 82 info.Clear(); 83 frame_num++; 84 } 85 } else { 86 uptr offset; 87 char filename[4096]; 88 if (proc_maps.GetObjectNameAndOffset(pc, &offset, 89 filename, sizeof(filename))) { 90 Printf(" #%zu 0x%zx (%s+0x%zx)\n", 91 frame_num, pc, StripPathPrefix(filename), offset); 92 } else { 93 Printf(" #%zu 0x%zx\n", frame_num, pc); 94 } 95 frame_num++; 96 } 97 } 98} 99 100uptr AsanStackTrace::GetCurrentPc() { 101 return GET_CALLER_PC(); 102} 103 104void AsanStackTrace::FastUnwindStack(uptr pc, uptr bp) { 105 CHECK(size == 0 && trace[0] == pc); 106 size = 1; 107 if (!asan_inited) return; 108 AsanThread *t = asanThreadRegistry().GetCurrent(); 109 if (!t) return; 110 uptr *frame = (uptr*)bp; 111 uptr *prev_frame = frame; 112 uptr *top = (uptr*)t->stack_top(); 113 uptr *bottom = (uptr*)t->stack_bottom(); 114 while (frame >= prev_frame && 115 frame < top - 2 && 116 frame > bottom && 117 size < max_size) { 118 uptr pc1 = frame[1]; 119 if (pc1 != pc) { 120 trace[size++] = pc1; 121 } 122 prev_frame = frame; 123 frame = (uptr*)frame[0]; 124 } 125} 126 127// On 32-bits we don't compress stack traces. 128// On 64-bits we compress stack traces: if a given pc differes slightly from 129// the previous one, we record a 31-bit offset instead of the full pc. 130SANITIZER_INTERFACE_ATTRIBUTE 131uptr AsanStackTrace::CompressStack(AsanStackTrace *stack, 132 u32 *compressed, uptr size) { 133#if __WORDSIZE == 32 134 // Don't compress, just copy. 135 uptr res = 0; 136 for (uptr i = 0; i < stack->size && i < size; i++) { 137 compressed[i] = stack->trace[i]; 138 res++; 139 } 140 if (stack->size < size) 141 compressed[stack->size] = 0; 142#else // 64 bits, compress. 143 uptr prev_pc = 0; 144 const uptr kMaxOffset = (1ULL << 30) - 1; 145 uptr c_index = 0; 146 uptr res = 0; 147 for (uptr i = 0, n = stack->size; i < n; i++) { 148 uptr pc = stack->trace[i]; 149 if (!pc) break; 150 if ((s64)pc < 0) break; 151 // Printf("C pc[%zu] %zx\n", i, pc); 152 if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) { 153 uptr offset = (s64)(pc - prev_pc); 154 offset |= (1U << 31); 155 if (c_index >= size) break; 156 // Printf("C co[%zu] offset %zx\n", i, offset); 157 compressed[c_index++] = offset; 158 } else { 159 uptr hi = pc >> 32; 160 uptr lo = (pc << 32) >> 32; 161 CHECK((hi & (1 << 31)) == 0); 162 if (c_index + 1 >= size) break; 163 // Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo); 164 compressed[c_index++] = hi; 165 compressed[c_index++] = lo; 166 } 167 res++; 168 prev_pc = pc; 169 } 170 if (c_index < size) 171 compressed[c_index] = 0; 172 if (c_index + 1 < size) 173 compressed[c_index + 1] = 0; 174#endif // __WORDSIZE 175 176 // debug-only code 177#if 0 178 AsanStackTrace check_stack; 179 UncompressStack(&check_stack, compressed, size); 180 if (res < check_stack.size) { 181 Printf("res %zu check_stack.size %zu; c_size %zu\n", res, 182 check_stack.size, size); 183 } 184 // |res| may be greater than check_stack.size, because 185 // UncompressStack(CompressStack(stack)) eliminates the 0x0 frames. 186 CHECK(res >= check_stack.size); 187 CHECK(0 == REAL(memcmp)(check_stack.trace, stack->trace, 188 check_stack.size * sizeof(uptr))); 189#endif 190 191 return res; 192} 193 194SANITIZER_INTERFACE_ATTRIBUTE 195void AsanStackTrace::UncompressStack(AsanStackTrace *stack, 196 u32 *compressed, uptr size) { 197#if __WORDSIZE == 32 198 // Don't uncompress, just copy. 199 stack->size = 0; 200 for (uptr i = 0; i < size && i < kStackTraceMax; i++) { 201 if (!compressed[i]) break; 202 stack->size++; 203 stack->trace[i] = compressed[i]; 204 } 205#else // 64 bits, uncompress 206 uptr prev_pc = 0; 207 stack->size = 0; 208 for (uptr i = 0; i < size && stack->size < kStackTraceMax; i++) { 209 u32 x = compressed[i]; 210 uptr pc = 0; 211 if (x & (1U << 31)) { 212 // Printf("U co[%zu] offset: %x\n", i, x); 213 // this is an offset 214 s32 offset = x; 215 offset = (offset << 1) >> 1; // remove the 31-byte and sign-extend. 216 pc = prev_pc + offset; 217 CHECK(pc); 218 } else { 219 // CHECK(i + 1 < size); 220 if (i + 1 >= size) break; 221 uptr hi = x; 222 uptr lo = compressed[i+1]; 223 // Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo); 224 i++; 225 pc = (hi << 32) | lo; 226 if (!pc) break; 227 } 228 // Printf("U pc[%zu] %zx\n", stack->size, pc); 229 stack->trace[stack->size++] = pc; 230 prev_pc = pc; 231 } 232#endif // __WORDSIZE 233} 234 235} // namespace __asan 236 237// ------------------ Interface -------------- {{{1 238using namespace __asan; // NOLINT 239 240void NOINLINE __asan_set_symbolize_callback( 241 __asan_symbolize_callback callback) { 242 symbolize_callback = callback; 243} 244