From owner-freebsd-hackers@FreeBSD.ORG  Wed Jun 22 14:31:46 2005
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Date: Wed, 22 Jun 2005 10:31:41 -0400 (EDT)
From: Daniel Eischen <deischen@freebsd.org>
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To: Peter Edwards <peadar.edwards@gmail.com>
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Cc: Charles Sprickman <spork@fasttrackmonkey.com>, hackers@freebsd.org,
	kamalp@acm.org
Subject: Re: Nagios and threads
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On Wed, 22 Jun 2005, Peter Edwards wrote:

> On 6/22/05, Kamal R. Prasad <kamalpr@yahoo.com> wrote:
> >
> > The child process should be able to call any system
> > calls it likes -without assuming that pthreads from
> > the parent process have been copied over to the child
> > process. I spose most implementations support that.
> >
>
> There's more to it than system calls, though (most (all?) of which
> will be async-signal-safe anyway). Simple example: any lock that the
> libc implementation needs to provide its functionality may be
> arbitrarily locked by some other thread: eg, one thread calls malloc()
> as another calls fork(): the original thread ceases to exist in the
> child while holding a lock in malloc, leaving malloc() unusable in the
> process.

We do protect the malloc lock across a fork(), but that's it.

-- 
DE