On Mon, May 16, 2011 at 12:07:45AM -0400, Jeff King wrote: > But what if we are not using pipes, but have an actual TCP socket? In > that case, I'm not sure what happens. We don't seem to do a half-duplex > shutdown() anywhere. So I'm concerned that we are still open for sending > from the remote's perspective, and we may deadlock. > > However, that would not necessarily be something introduced by your > patch; you would deadlock in receive_status, but prior to that it would > deadlock in the sideband demuxer. > > AFAICT, the only way to have an actual TCP connection instead of pipes > is for the push to go over git://, which is enabled almost nowhere. But > we should perhaps check for deadlock on failed pack-objects in that > case, both with and without your patch. Ugh, yeah, yet another deadlock. I can reproduce reliably with this: [in one terminal] mkdir daemon && git init --bare daemon/repo.git && git --git-dir=daemon/repo.git config daemon.receivepack true && git daemon --base-path=$PWD/daemon --export-all --verbose [in another] git init repo && cd repo && git remote add origin git://localhost/repo.git && echo content >file && git add file && git commit -a -m one && git push -f origin HEAD && echo content >>file && git commit -a -m two && sha1=`git rev-parse HEAD:file` && file=`echo $sha1 | sed 's,..,&/,'` && rm -fv .git/objects/$file && git push and this patch fixes it: diff --git a/builtin/send-pack.c b/builtin/send-pack.c index e2f4e21..b9da044 100644 --- a/builtin/send-pack.c +++ b/builtin/send-pack.c @@ -345,6 +345,13 @@ int send_pack(struct send_pack_args *args, ref->status = REF_STATUS_NONE; if (args->stateless_rpc) close(out); + /* in case we actually have a full-duplex socket + * and not two pipes; we can't use "out" because + * it has been closed already, but in the full-duplex + * case, "in" and "out" are merely dups of each other. + * We can't directly use "in" because it may be + * pointing to the sideband demuxer now */ + shutdown(fd[0], SHUT_WR); if (use_sideband) finish_async(&demux); return -1; It does call shutdown() on a non-socket in the pipe case. That should be a harmless noop, AFAIK. -Peff -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html