diff options
| -rw-r--r-- | runtime/backtrace_helper.cc | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/runtime/backtrace_helper.cc b/runtime/backtrace_helper.cc index 5b316fa101..74e613026f 100644 --- a/runtime/backtrace_helper.cc +++ b/runtime/backtrace_helper.cc @@ -66,7 +66,7 @@ struct UnwindHelper : public TLSData { } // Reparse process mmaps to detect newly loaded libraries. - bool Reparse() { return maps_.Reparse(); } + bool Reparse(bool* any_changed) { return maps_.Reparse(any_changed); } static UnwindHelper* Get(Thread* self, size_t max_depth) { UnwindHelper* tls = reinterpret_cast<UnwindHelper*>(self->GetCustomTLS(kTlsKey)); @@ -91,18 +91,20 @@ struct UnwindHelper : public TLSData { void BacktraceCollector::Collect() { unwindstack::Unwinder* unwinder = UnwindHelper::Get(Thread::Current(), max_depth_)->Unwinder(); if (!CollectImpl(unwinder)) { - // Reparse process mmaps to detect newly loaded libraries and retry. - UnwindHelper::Get(Thread::Current(), max_depth_)->Reparse(); - if (!CollectImpl(unwinder)) { + // Reparse process mmaps to detect newly loaded libraries and retry, + // but only if any maps changed (we don't want to hide racy failures). + bool any_changed; + UnwindHelper::Get(Thread::Current(), max_depth_)->Reparse(&any_changed); + if (!any_changed || !CollectImpl(unwinder)) { if (kStrictUnwindChecks) { - LOG(ERROR) << "Failed to unwind stack:"; std::vector<unwindstack::FrameData>& frames = unwinder->frames(); + LOG(ERROR) << "Failed to unwind stack (error " << unwinder->LastErrorCodeString() << "):"; for (auto it = frames.begin(); it != frames.end(); it++) { if (it == frames.begin() || std::prev(it)->map_name != it->map_name) { - LOG(ERROR) << " map_name " << it->map_name.c_str(); + LOG(ERROR) << " in " << it->map_name.c_str(); } - LOG(ERROR) << " " << std::setw(8) << std::setfill('0') << std::hex << - it->rel_pc << " " << it->function_name.c_str(); + LOG(ERROR) << " pc " << std::setw(8) << std::setfill('0') << std::hex << + it->rel_pc << " " << it->function_name.c_str(); } LOG(FATAL); } @@ -123,30 +125,28 @@ bool BacktraceCollector::CollectImpl(unwindstack::Unwinder* unwinder) { out_frames_[num_frames_++] = static_cast<uintptr_t>(it->pc); // Expected early end: Instrumentation breaks unwinding (b/138296821). - size_t align = GetInstructionSetAlignment(kRuntimeISA); - if (RoundUp(it->pc, align) == reinterpret_cast<uintptr_t>(GetQuickInstrumentationExitPc())) { + // Inexact compare because the unwinder does not give us exact return address, + // but rather it tries to guess the address of the preceding call instruction. + size_t exit_pc = reinterpret_cast<size_t>(GetQuickInstrumentationExitPc()); + if (exit_pc - 4 <= it->pc && it->pc <= exit_pc) { return true; } if (kStrictUnwindChecks) { if (it->function_name.empty()) { return false; - } else if (it->function_name == "main" || it->function_name == "start_thread") { + } + if (it->function_name == "main" || + it->function_name == "start_thread" || + it->function_name == "__start_thread") { return true; } } } } - if (unwinder->LastErrorCode() == unwindstack::ERROR_INVALID_MAP) { - return false; - } - if (kStrictUnwindChecks) { - // We have not found "main". That is ok if we stopped the backtrace early. - return unwinder->NumFrames() == max_depth_; - } - - return true; + unwindstack::ErrorCode error = unwinder->LastErrorCode(); + return error == unwindstack::ERROR_NONE || error == unwindstack::ERROR_MAX_FRAMES_EXCEEDED; } #else |