Hi Lasse, On Feb 24 20:37, Lasse Collin wrote: > On 2015-02-24 Corinna Vinschen wrote: > > On Feb 24 15:54, Lasse Collin wrote: > > > Many other pthread functions are similar in sense that they must > > > never return EINTR. A bug similar to the one in pthread::join exist > > > in pthread_mutex::lock. If SA_RESTART isn't used, signals can make > > > multiple threads get a lock on the same mutex at the same time. A > > > test program is attached. Adding cw_sig_restart to the cygwait call > > > in pthread_mutex::lock fixes this. > > > > Can you collect the info which functions are affected so that lazy me > > just has to apply the cw_sig_restart patches in bulk? > > I grepped for cygwait uses earlier but I don't understand the code well > enough to be sure about anything. The following is pretty much > guessing, but hopefully there's something useful still. > > These look the most suspicious to me, possibly needing cw_sig_restart: > > thread.h fast_mutex::lock > fhandler_tape.cc fhandler_dev_tape::_lock > > When looking for things needing cw_sig_restart, I started to wonder if > cw_sig_eintr is used properly in all cases. Often the caller of > cygwait + cw_sig_eintr will also conditionally call > _my_tls.call_signal_handler, but the following functions don't. The > comment in handle_sigsuspend makes me think that this may be a false > alarm but I mention these just in case. > > exceptions.cc handle_sigsuspend > posix_ipc.cc ipc_mutex_lock > signal.cc clock_nanosleep > signal.cc sigwaitinfo > thread.cc pthread_cond::wait > thread.cc semaphore::_timedwait > thread.cc semaphore::_wait
The signal code has gone through a couple of iterations so there's a chance that some places do useless stuff; detritus from former iterations. > In the following functions the situation is kind of reversed. Those > functions call _my_tls.call_signal_handler even though cw_sig_eintr > wasn't specified. cygwait will already have called the signal handler > since cw_sig has been specified via cygwait(DWORD). So I guess in these > functions the signal handler might get called twice. > > fhandler_dsp.cc fhandler_dev_dsp::Audio_out::waitforspace > fhandler_dsp.cc fhandler_dev_dsp::Audio_in::waitfordata Cool, thanks for looking so closely. I wasn't expecting that, rather just a look through the pthread functions but this is very helpful. I'll check these code snippets in the next couple of days, maybe even tomorrow. Thanks again, Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat
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