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Reply-To: <lar@cs.york.ac.uk>
From: "Laramie Leavitt" <laramie.leavitt@btinternet.com>
To: "Sane, Purushottam" <Sane_Purushottam@emc.com>
Cc: <linux-kernel@vger.kernel.org>
Subject: RE: fork and pthreads
Date: Fri, 16 Mar 2001 23:11:14 -0000
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> Nitin Sane Wrote:
> > On Fri, Mar 16, 2001 at 06:52:26PM +0100, Richard Guenther wrote:
> > > Well, using pthreads and forking in them seems to trigger libc
> > > bugs (read: SIGSEGvs) here under certain conditions (happens,
> > > after I introduced signal handlers and using pthread_sigmask,
> > > I think), so hangs should be definitely possible, too...
> > 
> > You must pretty much avoid using signal handlers with pthreads.
> > In stead, you need to carefully setup things such that most signals
> > are blocked in most threads and a single thread (or selected set
> > of threads) does a sigwait for signals of interest.  Most good
> > pthreads books talk about this issue, as does the DCE documentation.
> 
> I am not using any signals. All the signals are blocked with SIG_IGN
> 

You know, I have been running into that exact same problem, except that
I don't fork at all.  I start up my process and nearly immediately try
and spawn a few threads.  The calling thread blocks indefinately in
a __sigsuspend(), but is apparently delivered an unknown signal.
The spawned thread executes normally.

It appears to be fixed when I compile with -D_REENTRANT, but I am not
certain...

Laramie

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