Discards frames for code within library.
When doing a local unwind, do not include the frames that come
from either libunwind or libbacktrace.
Bug: 11518609
Change-Id: I0ec8d823aebbfa0903e61b16b7e5663f3fd65e78
diff --git a/libbacktrace/BacktraceCurrent.cpp b/libbacktrace/BacktraceCurrent.cpp
index b7190e2..fd1f4da 100644
--- a/libbacktrace/BacktraceCurrent.cpp
+++ b/libbacktrace/BacktraceCurrent.cpp
@@ -14,6 +14,7 @@
* limitations under the License.
*/
+#define _GNU_SOURCE 1
#include <errno.h>
#include <stdint.h>
#include <string.h>
@@ -73,6 +74,16 @@
return UnwindFromContext(num_ignore_frames, nullptr);
}
+bool BacktraceCurrent::DiscardFrame(const backtrace_frame_data_t& frame) {
+ if (BacktraceMap::IsValid(frame.map)) {
+ const std::string library = basename(frame.map.name.c_str());
+ if (library == "libunwind.so" || library == "libbacktrace.so") {
+ return true;
+ }
+ }
+ return false;
+}
+
static pthread_mutex_t g_sigaction_mutex = PTHREAD_MUTEX_INITIALIZER;
static void SignalHandler(int, siginfo_t*, void* sigcontext) {
diff --git a/libbacktrace/BacktraceCurrent.h b/libbacktrace/BacktraceCurrent.h
index 81ea81d..8aad36d 100644
--- a/libbacktrace/BacktraceCurrent.h
+++ b/libbacktrace/BacktraceCurrent.h
@@ -46,6 +46,9 @@
bool Unwind(size_t num_ignore_frames, ucontext_t* ucontext) override;
+protected:
+ bool DiscardFrame(const backtrace_frame_data_t& frame);
+
private:
bool UnwindThread(size_t num_ignore_frames);
diff --git a/libbacktrace/UnwindCurrent.cpp b/libbacktrace/UnwindCurrent.cpp
index 12e2890..67e583f 100644
--- a/libbacktrace/UnwindCurrent.cpp
+++ b/libbacktrace/UnwindCurrent.cpp
@@ -99,25 +99,30 @@
break;
}
- if (num_ignore_frames == 0) {
- frames_.resize(num_frames+1);
- backtrace_frame_data_t* frame = &frames_.at(num_frames);
- frame->num = num_frames;
- frame->pc = static_cast<uintptr_t>(pc);
- frame->sp = static_cast<uintptr_t>(sp);
- frame->stack_size = 0;
+ frames_.resize(num_frames+1);
+ backtrace_frame_data_t* frame = &frames_.at(num_frames);
+ frame->num = num_frames;
+ frame->pc = static_cast<uintptr_t>(pc);
+ frame->sp = static_cast<uintptr_t>(sp);
+ frame->stack_size = 0;
- if (num_frames > 0) {
- // Set the stack size for the previous frame.
- backtrace_frame_data_t* prev = &frames_.at(num_frames-1);
- prev->stack_size = frame->sp - prev->sp;
+ FillInMap(frame->pc, &frame->map);
+ // Check to see if we should skip this frame because it's coming
+ // from within the library, and we are doing a local unwind.
+ if (ucontext != nullptr || num_frames != 0 || !DiscardFrame(*frame)) {
+ if (num_ignore_frames == 0) {
+ // GetFunctionName is an expensive call, only do it if we are
+ // keeping the frame.
+ frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
+ if (num_frames > 0) {
+ // Set the stack size for the previous frame.
+ backtrace_frame_data_t* prev = &frames_.at(num_frames-1);
+ prev->stack_size = frame->sp - prev->sp;
+ }
+ num_frames++;
+ } else {
+ num_ignore_frames--;
}
-
- frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
- FillInMap(frame->pc, &frame->map);
- num_frames++;
- } else {
- num_ignore_frames--;
}
ret = unw_step (cursor.get());
} while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp
index d408856..5de80b1 100644
--- a/libbacktrace/backtrace_test.cpp
+++ b/libbacktrace/backtrace_test.cpp
@@ -14,6 +14,7 @@
* limitations under the License.
*/
+#define _GNU_SOURCE 1
#include <dirent.h>
#include <errno.h>
#include <inttypes.h>
@@ -200,6 +201,23 @@
return false;
}
+TEST(libbacktrace, local_no_unwind_frames) {
+ // Verify that a local unwind does not include any frames within
+ // libunwind or libbacktrace.
+ std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), getpid()));
+ ASSERT_TRUE(backtrace->Unwind(0));
+
+ ASSERT_TRUE(backtrace->NumFrames() != 0);
+ for (const auto& frame : *backtrace ) {
+ if (BacktraceMap::IsValid(frame.map)) {
+ const std::string name = basename(frame.map.name.c_str());
+ ASSERT_TRUE(name != "libunwind.so" && name != "libbacktrace.so")
+ << DumpFrames(backtrace.get());
+ }
+ break;
+ }
+}
+
TEST(libbacktrace, local_trace) {
ASSERT_NE(test_level_one(1, 2, 3, 4, VerifyLevelBacktrace, nullptr), 0);
}