3 libstdc++ tests fail at random
Jonathan Wakely
jwakely.gcc@gmail.com
Sun Dec 8 22:18:00 GMT 2013
On 7 December 2013 17:28, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Sat, Dec 7, 2013 at 9:26 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Sat, Dec 7, 2013 at 9:09 AM, Jakub Jelinek <jakub@redhat.com> wrote:
>>>> >FAIL: 30_threads/async/async.cc execution test
>>>
>>> async.exe: /usr/src/gcc/libstdc++-v3/testsuite/30_threads/async/async.cc:66: void test02(): Assertion `status == std::future_status::ready' failed.
>>>
>>> This one fails pretty frequently for me, 6 times out of last 12 i686-linux
>>
>> Same here.
>>
>>> bootstraps/regtests, starting with ~ Nov 21th bootstrap (but before that
>>
>> It started for me around revision 205144.
>>
>
> http://gcc.gnu.org/ml/gcc-cvs/2013-11/msg00869.html
>
> changed 30_threads/async/async.cc.
My recent change to that test introduced a race, the main thread could
wake up and check for readiness before the shared state had been made
ready. Fixed by this patch.
Tested x86_64-linux and i686-linux, committed to trunk.
2013-12-08 Jonathan Wakely <jwakely.gcc@gmail.com>
* testsuite/30_threads/async/async.cc: Fix race condition in test.
-------------- next part --------------
commit 2141b30307e7802625e72eba3037c0528fcaa76d
Author: Jonathan Wakely <jwakely.gcc@gmail.com>
Date: Sun Dec 8 21:35:22 2013 +0000
* testsuite/30_threads/async/async.cc: Fix race condition in test.
diff --git a/libstdc++-v3/testsuite/30_threads/async/async.cc b/libstdc++-v3/testsuite/30_threads/async/async.cc
index 1f94494..05fd23c 100644
--- a/libstdc++-v3/testsuite/30_threads/async/async.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/async.cc
@@ -29,23 +29,18 @@
using namespace std;
-struct work {
- typedef void result_type;
- void operator()(mutex& m, condition_variable& cv)
- {
- unique_lock<mutex> l(m);
- cv.notify_one();
- }
-};
+void work(mutex& m)
+{
+ unique_lock<mutex> l(m);
+}
void test01()
{
mutex m;
- condition_variable cv;
unique_lock<mutex> l(m);
- future<void> f1 = async(launch::async, work(), ref(m), ref(cv));
- cv.wait(l);
- f1.get();
+ future<void> f1 = async(launch::async, &work, ref(m));
+ l.unlock(); // allow async thread to proceed
+ f1.get(); // wait for it to finish
}
void test02()
@@ -53,15 +48,15 @@ void test02()
bool test __attribute__((unused)) = true;
mutex m;
- condition_variable cv;
unique_lock<mutex> l(m);
- future<void> f1 = async(launch::async, work(), ref(m), ref(cv));
+ future<void> f1 = async(launch::async, &work, ref(m));
std::future_status status;
status = f1.wait_for(std::chrono::milliseconds(1));
VERIFY( status == std::future_status::timeout );
status = f1.wait_until(std::chrono::system_clock::now());
VERIFY( status == std::future_status::timeout );
- cv.wait(l);
+ l.unlock(); // allow async thread to proceed
+ f1.wait(); // wait for it to finish
status = f1.wait_for(std::chrono::milliseconds(0));
VERIFY( status == std::future_status::ready );
status = f1.wait_until(std::chrono::system_clock::now());
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