From: Jonathan Nieder <jrnieder@gmail.com>
Date: Mon, 18 Apr 2011 05:34:06 GMT
Subject: Re: [RFC] upload-pack deadlock
Message-ID: <20110418053406.GA5256@elie>
In-Reply-To: <20110406213333.GA18481@sigill.intra.peff.net>

Jeff King wrote:

> Subject: [PATCH] upload-pack: start pack-objects before async rev-list
>
> In a pthread-enabled version of upload-pack, there's a race condition
> that can cause a deadlock on the fflush(NULL) we call from run-command.
[...]
> To fix this, we swap the start order: we start the
> pack-objects reader first, and then the rev-list writer
> after. Thus the problematic fflush(NULL) happens before we
> even open the new file descriptor (and even if it didn't,
> flushing should no longer block, as the reader at the end of
> the pipe is now active).
>
> Signed-off-by: Jeff King <peff@peff.net>

t5500.12 "fetch same depth in shallow repo" reproducibly hangs[1] on
the HURD without this patch and passes with it.  I had just assumed it
was some weird hurd thing.  Thanks for figuring it out.

Tested-by: Jonathan Nieder <jrnieder@gmail.com>

[1] http://bugs.debian.org/607346