Re: [PATCH 0/5] fix deadlock in git-push

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 20, 2016, 21:17 UTC
Message-ID: <xmqqwpnst1yb.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20160419223945.GA18055@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 14 quoted lines

> The first patch below fixes the deadlock. Unfortunately, it turns it
> into a likely SIGPIPE death. Which is an improvement, but not ideal.
>
> Patches 2 and 3 address that by fixing the way we handle SIGPIPE in
> async threads.
>
> Patches 4 and 5 are cleanups to earlier topics that are enabled by the
> new SIGPIPE handling.
>
>   [1/5]: send-pack: close demux pipe before finishing async process
>   [2/5]: run-command: teach async threads to ignore SIGPIPE
>   [3/5]: send-pack: isolate sigpipe in demuxer thread
>   [4/5]: fetch-pack: isolate sigpipe in demuxer thread
>   [5/5]: t5504: drop sigpipe=ok from push tests

Thanks for a very well explained series.

We do not call finish_async (rather, we do not use async) from that many places, and from a cursory look this codepath is the only case where we may encounter this kind of deadlock (the ones in receive-pack is about relaying the error messages back to the other end over sideband multiplexing)?