Unexpected EINVAL from pthread_join
Wed Feb 25 19:23:00 GMT 2015
On Feb 24 22:20, Corinna Vinschen wrote:
> 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
FYI, I fixed these plus pthread_mutex::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
This works as desired, afaics.
> > 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
> > 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
I'm still mulling over the rest of your list...
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Maintainer cygwin AT cygwin DOT com
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