multithreading broken in Cygwin 3.5.3

Wed May 29 10:06:19 GMT 2024

On 2024年5月23日 20:09:09 +0200
Bruno Haible wrote:
> In Cygwin 3.5.3, on different machines, I see 3 Gnulib tests failing by
> timeout that worked perfectly fine in Cygwin 3.4.6 and older:
> FAIL: test-call_once2.exe
> FAIL: test-lock.exe
> FAIL: test-pthread-once2.exe
>> Find here attached a simplified version of test-pthread-once2.c.
> Compile and run:
> $ x86_64-pc-cygwin-gcc -Wall foo.c
> $ ./a
>> Expected behaviour: Termination within 1 minute.
> Actual behaviour: Terminates by timeout after 10 minutes.
>> When I change
> #define ENABLE_DEBUGGING 0
> to
> #define ENABLE_DEBUGGING 1
> the test does lots of output and terminates within 20 seconds.
> Therefore I can't really tell where the problem comes from.
> But I do see some changes in
> $ git diff cygwin-3.4.6 cygwin-3.5.3 winsup/cygwin/thread.cc
> $ git diff cygwin-3.4.6 cygwin-3.5.3 winsup/testsuite/winsup.api/pthread

Thanks for the report.
As you mentioned in private mail to me, this seems to be a regression of
pthread::once() introduced by
commit 2c5433e5da8216aaf7458e50c63683c68fb0d3e8.
I'll submit a patch for that issue shortly.
-- 
Takashi Yano <takashi.yano@nifty.ne.jp>