From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2155) id 236123858C33; Mon, 22 Jan 2024 11:49:57 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 236123858C33 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com; s=default; t=1705924197; bh=NF1f/REk4o4dPHu+v82O7nuUOQXszSILu8hLl8rNM+g=; h=Date:From:To:Subject:Reply-To:References:In-Reply-To:From; b=QP63IMnyoFWaDE9Zaey6JGgAfZCfkjnmFcC7AeLSdnKCpl3asQhPUQQtmrD9LsFep 58mHphkocaOWkjaW3d8BaTMln/l6fE/ko3LnpaxcF4UpgMOEE/snADVawFAsBouTUE jtIPHso8UyaiMxt1vklVsKas1dQH/WFqhXxJPI2Y= Received: by calimero.vinschen.de (Postfix, from userid 500) id 5BA7AA80733; Mon, 22 Jan 2024 12:49:55 +0100 (CET) Date: Mon, 22 Jan 2024 12:49:55 +0100 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: Possiblly bug of cygwin1.dll Message-ID: Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <20240120131825.4157c259fe058155137d6fe0@nifty.ne.jp> <20240120141349.cde31e62177a0405b0ee9934@nifty.ne.jp> <87v87ov03x.fsf@Gerda.invalid> <20240120212427.1e69fd3655ece73ecd508def@nifty.ne.jp> <20240121201051.795a4405576a97ab8729e273@nifty.ne.jp> <87fryqizl3.fsf@> <20240122123023.b8eaac0e50d1e8856f44a115@nifty.ne.jp> <20240122201602.0a172f5965821f6e8d6afb96@nifty.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240122201602.0a172f5965821f6e8d6afb96@nifty.ne.jp> List-Id: On Jan 22 20:16, Takashi Yano via Cygwin wrote: > On Mon, 22 Jan 2024 10:57:48 +0100 > Corinna Vinschen wrote: > > On Jan 22 10:25, Corinna Vinschen via Cygwin wrote: > > > On Jan 22 12:30, Takashi Yano via Cygwin wrote: > > > > PATCH2: (for cygwin) > > > > Avoid handle leak caused when non-static pthread_once_t is initialized > > > > with PTHREAD_ONCE_INIT > > > > diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc > > > > index 7bb4f9fc8..127569160 100644 > > > > --- a/winsup/cygwin/thread.cc > > > > +++ b/winsup/cygwin/thread.cc > > > > @@ -2060,6 +2060,9 @@ pthread::once (pthread_once_t *once_control, void (*init_routine) (void)) > > > > { > > > > init_routine (); > > > > once_control->state = 1; > > > > + pthread_mutex_unlock (&once_control->mutex); > > > > + while (pthread_mutex_destroy (&once_control->mutex) == EBUSY); > > > > + return 0; > > > > } > > > > /* Here we must remove our cancellation handler */ > > > > pthread_mutex_unlock (&once_control->mutex); > > > > > > I see what you're doing here. Wouldn't it be simpler, though, to do this? > > > > > > diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc > > > index 7bb4f9fc8341..7ec3aace395d 100644 > > > --- a/winsup/cygwin/thread.cc > > > +++ b/winsup/cygwin/thread.cc > > > @@ -2063,6 +2063,7 @@ pthread::once (pthread_once_t *once_control, void (*init_routine) (void)) > > > } > > > /* Here we must remove our cancellation handler */ > > > > Strange enough, this comment accompanies the code since its inception > > in 2001. It says explicitly "remove" the cancellation handler. > > That sounds like the idea was right, just the programmer forgot about > > it afterwards... > > I am not sure what 'cancellation handler' means here. Is it the > event handler in pthread_mutex_t? Aaah, no. I just read and re-read the stuff and it occured to me that this is based on the preceeding, longer comment in pthread::once. Theoretically, the comments say, we need to set up a cancellation handler so pthread_once becomes cancellable. However, I don't find this in the standards. pthread_once is neither one of the required cancellation points, nor one of the optional cancellation points. So now I wonder if we shouldn't just get rid of the cokmments talking about the cancellation in pthread::once entirely. Corinna