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Fix flaky signal tests.

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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
This commit is contained in:
Christopher Ferris 2019-01-18 16:33:27 -08:00
parent b26b07d845
commit bc6a7e51e4
1 changed files with 15 additions and 3 deletions
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18
libunwindstack/tests/UnwindTest.cpp
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@ -47,6 +47,7 @@ namespace unwindstack {
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 @@ static void SignalHandler(int, siginfo_t*, void* sigcontext) {
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 @@ static void VerifyUnwind(pid_t pid, Maps* maps, Regs* regs,
// 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 @@ extern "C" void InnerFunction(TestTypeEnum test_type) {
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 @@ TEST_F(UnwindTest, from_context) {
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;