[debbugs-tracker] bug#18222: closed (24.3.92; fork handlers in gmalloc.c can lead to deadlock)

[GNU bug Tracking System]

Your message dated Thu, 28 Aug 2014 15:40:18 -0400
with message-id <address@hidden>
and subject line Re: bug#18222: 24.3.92; fork handlers in gmalloc.c can lead to 
deadlock
has caused the debbugs.gnu.org bug report #18222,
regarding 24.3.92; fork handlers in gmalloc.c can lead to deadlock
to be marked as done.

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18222: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=18222
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> --- Begin Message ---
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>
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> Subject: 
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> 24.3.92; fork handlers in gmalloc.c can lead to deadlock
>
>
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> Date: 
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> Fri, 08 Aug 2014 09:09:31 -0400
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> User-agent: 
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> Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0
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>
>
>
> malloc_enable_thread() in gmalloc.c calls pthread_atfork to set up fork 
> handlers.  There are a couple of problems with this, but the immediate 
> reason for this bug report is a problem on Cygwin that was reported in 
> the thread starting at
>
>   https://cygwin.com/ml/cygwin/2014-07/msg00387.html
>
> and continuing at
>
>   https://cygwin.com/ml/cygwin/2014-08/msg00001.html.
>
> The issue is that the 'prepare' fork handler locks the pthread_mutexes 
> prior to forking, and the ensuing processing of the fork command by the 
> Cygwin DLL leads to a call to malloc in the same thread, resulting in 
> deadlock.  This is a long-standing problem, but it was masked until 
> recently by the fact that pthread_mutexes on Cygwin were ERRORCHECK 
> mutexes by default.  As of Cygwin 1.7.31, pthread_mutexes are now NORMAL 
> mutexes by default, so the problem has shown up.
>
> A simple short-term workaround would be to explicitly set the mutexes to 
> be ERRORCHECK or RECURSIVE mutexes on Cygwin, thereby restoring the 
> previous behavior.  But this does not seem like the right long-term 
> solution, for the reasons explained here:
>
>   https://cygwin.com/ml/cygwin/2014-08/msg00161.html
>   https://cygwin.com/ml/cygwin/2014-08/msg00175.html
>
> I know nothing about this other than what I learned from the two 
> messages above, so I would appreciate some guidance.
>
> Ken
>
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#18222: 24.3.92; fork handlers in gmalloc.c can lead to deadlock
>
>
>
>
> Date: 
>
> Thu, 28 Aug 2014 15:40:18 -0400
>
>
>
>
> User-agent: 
>
> Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0
>
>
>
>
> Version: 24.5
>
> > Closing a bug doesn't prevent further discussion.
> > (In my experience not closing it just means people tend to forget to do
> > that later.)
>
> OK. Closed.
>
>
>
> --- End Message ---