Fix flaky signal tests.
The signal tests that send a SIGUSR1 signal to a remote process, can
lead to a case where the code winds up in a location for which the
unwind information is not 100% accurate. This happens near the
end of the atomic functions which manipulate the stack right before
returning, but do not have separate cfi instructions for those last
few instructions.
Add a new test type for the from_context test that will wait explicitly
for the global g_finish and not piggy back on the remote test type.
Bug: 122902885
Test: Ran flaky tests 1000 times without failure on a taimen.
Change-Id: I7d0c9b016e3a3a2c0c0949cf74af11d7785a008c
diff --git a/libunwindstack/tests/UnwindTest.cpp b/libunwindstack/tests/UnwindTest.cpp
index a91bd95..c747eab 100644
--- a/libunwindstack/tests/UnwindTest.cpp
+++ b/libunwindstack/tests/UnwindTest.cpp
@@ -47,6 +47,7 @@
enum TestTypeEnum : uint8_t {
TEST_TYPE_LOCAL_UNWINDER = 0,
TEST_TYPE_LOCAL_UNWINDER_FROM_PID,
+ TEST_TYPE_LOCAL_WAIT_FOR_FINISH,
TEST_TYPE_REMOTE,
TEST_TYPE_REMOTE_WITH_INVALID_CALL,
};
@@ -79,7 +80,10 @@
extern "C" void SignalInnerFunction() {
g_signal_ready_for_remote = true;
- while (!g_finish.load()) {
+ // Avoid any function calls because not every instruction will be
+ // unwindable.
+ // This method of looping is only used when testing a remote unwind.
+ while (true) {
}
}
@@ -134,6 +138,11 @@
// off. If this doesn't happen, then all of the calls will be optimized
// away.
extern "C" void InnerFunction(TestTypeEnum test_type) {
+ if (test_type == TEST_TYPE_LOCAL_WAIT_FOR_FINISH) {
+ while (!g_finish.load()) {
+ }
+ return;
+ }
if (test_type == TEST_TYPE_REMOTE || test_type == TEST_TYPE_REMOTE_WITH_INVALID_CALL) {
g_ready_for_remote = true;
g_ready = true;
@@ -141,7 +150,10 @@
void (*crash_func)() = nullptr;
crash_func();
}
- while (!g_finish.load()) {
+ // Avoid any function calls because not every instruction will be
+ // unwindable.
+ // This method of looping is only used when testing a remote unwind.
+ while (true) {
}
return;
}
@@ -271,7 +283,7 @@
std::atomic_int tid(0);
std::thread thread([&]() {
tid = syscall(__NR_gettid);
- OuterFunction(TEST_TYPE_REMOTE);
+ OuterFunction(TEST_TYPE_LOCAL_WAIT_FOR_FINISH);
});
struct sigaction act, oldact;