| //===-- asan_stack.cc -----------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is a part of AddressSanitizer, an address sanity checker. |
| // |
| // Code for ASan stack trace. |
| //===----------------------------------------------------------------------===// |
| #include "asan_interceptors.h" |
| #include "asan_lock.h" |
| #include "asan_stack.h" |
| #include "asan_thread.h" |
| #include "asan_thread_registry.h" |
| #include "sanitizer_common/sanitizer_procmaps.h" |
| #include "sanitizer_common/sanitizer_symbolizer.h" |
| |
| #ifdef ASAN_USE_EXTERNAL_SYMBOLIZER |
| extern bool |
| ASAN_USE_EXTERNAL_SYMBOLIZER(const void *pc, char *out, int out_size); |
| #endif |
| |
| namespace __asan { |
| |
| // ----------------------- AsanStackTrace ----------------------------- {{{1 |
| // PCs in stack traces are actually the return addresses, that is, |
| // addresses of the next instructions after the call. That's why we |
| // decrement them. |
| static uptr patch_pc(uptr pc) { |
| #ifdef __arm__ |
| // Cancel Thumb bit. |
| pc = pc & (~1); |
| #endif |
| return pc - 1; |
| } |
| |
| #if defined(ASAN_USE_EXTERNAL_SYMBOLIZER) |
| void AsanStackTrace::PrintStack(uptr *addr, uptr size) { |
| for (uptr i = 0; i < size && addr[i]; i++) { |
| uptr pc = addr[i]; |
| if (i < size - 1 && addr[i + 1]) |
| pc = patch_pc(pc); |
| char buff[4096]; |
| ASAN_USE_EXTERNAL_SYMBOLIZER((void*)pc, buff, sizeof(buff)); |
| AsanPrintf(" #%zu 0x%zx %s\n", i, pc, buff); |
| } |
| } |
| |
| #else // ASAN_USE_EXTERNAL_SYMBOLIZER |
| void AsanStackTrace::PrintStack(uptr *addr, uptr size) { |
| ProcessMaps proc_maps; |
| uptr frame_num = 0; |
| for (uptr i = 0; i < size && addr[i]; i++) { |
| uptr pc = addr[i]; |
| if (i < size - 1 && addr[i + 1]) |
| pc = patch_pc(pc); |
| AddressInfo addr_frames[64]; |
| uptr addr_frames_num = 0; |
| if (flags()->symbolize) { |
| addr_frames_num = SymbolizeCode(pc, addr_frames, |
| ASAN_ARRAY_SIZE(addr_frames)); |
| } |
| if (addr_frames_num > 0) { |
| for (uptr j = 0; j < addr_frames_num; j++) { |
| AddressInfo &info = addr_frames[j]; |
| AsanPrintf(" #%zu 0x%zx", frame_num, pc); |
| if (info.function) { |
| AsanPrintf(" in %s", info.function); |
| } |
| if (info.file) { |
| AsanPrintf(" %s:%d:%d", info.file, info.line, info.column); |
| } else if (info.module) { |
| AsanPrintf(" (%s+0x%zx)", info.module, info.module_offset); |
| } |
| AsanPrintf("\n"); |
| info.Clear(); |
| frame_num++; |
| } |
| } else { |
| uptr offset; |
| char filename[4096]; |
| if (proc_maps.GetObjectNameAndOffset(pc, &offset, |
| filename, sizeof(filename))) { |
| AsanPrintf(" #%zu 0x%zx (%s+0x%zx)\n", frame_num, pc, filename, |
| offset); |
| } else { |
| AsanPrintf(" #%zu 0x%zx\n", frame_num, pc); |
| } |
| frame_num++; |
| } |
| } |
| } |
| #endif // ASAN_USE_EXTERNAL_SYMBOLIZER |
| |
| uptr AsanStackTrace::GetCurrentPc() { |
| return GET_CALLER_PC(); |
| } |
| |
| void AsanStackTrace::FastUnwindStack(uptr pc, uptr bp) { |
| CHECK(size == 0 && trace[0] == pc); |
| size = 1; |
| if (!asan_inited) return; |
| AsanThread *t = asanThreadRegistry().GetCurrent(); |
| if (!t) return; |
| uptr *frame = (uptr*)bp; |
| uptr *prev_frame = frame; |
| uptr *top = (uptr*)t->stack_top(); |
| uptr *bottom = (uptr*)t->stack_bottom(); |
| while (frame >= prev_frame && |
| frame < top - 2 && |
| frame > bottom && |
| size < max_size) { |
| uptr pc1 = frame[1]; |
| if (pc1 != pc) { |
| trace[size++] = pc1; |
| } |
| prev_frame = frame; |
| frame = (uptr*)frame[0]; |
| } |
| } |
| |
| // On 32-bits we don't compress stack traces. |
| // On 64-bits we compress stack traces: if a given pc differes slightly from |
| // the previous one, we record a 31-bit offset instead of the full pc. |
| uptr AsanStackTrace::CompressStack(AsanStackTrace *stack, |
| u32 *compressed, uptr size) { |
| #if __WORDSIZE == 32 |
| // Don't compress, just copy. |
| uptr res = 0; |
| for (uptr i = 0; i < stack->size && i < size; i++) { |
| compressed[i] = stack->trace[i]; |
| res++; |
| } |
| if (stack->size < size) |
| compressed[stack->size] = 0; |
| #else // 64 bits, compress. |
| uptr prev_pc = 0; |
| const uptr kMaxOffset = (1ULL << 30) - 1; |
| uptr c_index = 0; |
| uptr res = 0; |
| for (uptr i = 0, n = stack->size; i < n; i++) { |
| uptr pc = stack->trace[i]; |
| if (!pc) break; |
| if ((s64)pc < 0) break; |
| // Printf("C pc[%zu] %zx\n", i, pc); |
| if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) { |
| uptr offset = (s64)(pc - prev_pc); |
| offset |= (1U << 31); |
| if (c_index >= size) break; |
| // Printf("C co[%zu] offset %zx\n", i, offset); |
| compressed[c_index++] = offset; |
| } else { |
| uptr hi = pc >> 32; |
| uptr lo = (pc << 32) >> 32; |
| CHECK((hi & (1 << 31)) == 0); |
| if (c_index + 1 >= size) break; |
| // Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo); |
| compressed[c_index++] = hi; |
| compressed[c_index++] = lo; |
| } |
| res++; |
| prev_pc = pc; |
| } |
| if (c_index < size) |
| compressed[c_index] = 0; |
| if (c_index + 1 < size) |
| compressed[c_index + 1] = 0; |
| #endif // __WORDSIZE |
| |
| // debug-only code |
| #if 0 |
| AsanStackTrace check_stack; |
| UncompressStack(&check_stack, compressed, size); |
| if (res < check_stack.size) { |
| Printf("res %zu check_stack.size %zu; c_size %zu\n", res, |
| check_stack.size, size); |
| } |
| // |res| may be greater than check_stack.size, because |
| // UncompressStack(CompressStack(stack)) eliminates the 0x0 frames. |
| CHECK(res >= check_stack.size); |
| CHECK(0 == REAL(memcmp)(check_stack.trace, stack->trace, |
| check_stack.size * sizeof(uptr))); |
| #endif |
| |
| return res; |
| } |
| |
| void AsanStackTrace::UncompressStack(AsanStackTrace *stack, |
| u32 *compressed, uptr size) { |
| #if __WORDSIZE == 32 |
| // Don't uncompress, just copy. |
| stack->size = 0; |
| for (uptr i = 0; i < size && i < kStackTraceMax; i++) { |
| if (!compressed[i]) break; |
| stack->size++; |
| stack->trace[i] = compressed[i]; |
| } |
| #else // 64 bits, uncompress |
| uptr prev_pc = 0; |
| stack->size = 0; |
| for (uptr i = 0; i < size && stack->size < kStackTraceMax; i++) { |
| u32 x = compressed[i]; |
| uptr pc = 0; |
| if (x & (1U << 31)) { |
| // Printf("U co[%zu] offset: %x\n", i, x); |
| // this is an offset |
| s32 offset = x; |
| offset = (offset << 1) >> 1; // remove the 31-byte and sign-extend. |
| pc = prev_pc + offset; |
| CHECK(pc); |
| } else { |
| // CHECK(i + 1 < size); |
| if (i + 1 >= size) break; |
| uptr hi = x; |
| uptr lo = compressed[i+1]; |
| // Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo); |
| i++; |
| pc = (hi << 32) | lo; |
| if (!pc) break; |
| } |
| // Printf("U pc[%zu] %zx\n", stack->size, pc); |
| stack->trace[stack->size++] = pc; |
| prev_pc = pc; |
| } |
| #endif // __WORDSIZE |
| } |
| |
| } // namespace __asan |