From: Phillip Wood <phillip.wood123@gmail•com>
To: "Carlo Marcelo Arenas Belón" <carenas@gmail•com>, git@vger•kernel.org
Cc: yoshfuji@linux-ipv6•org, kristofferhaugsbakk@fastmail•com
Subject: Re: [PATCH v2] daemon: correctly handle soft accept() errors in service_loop
Date: Fri, 27 Jun 2025 09:38:47 +0100 [thread overview]
Message-ID: <08804dbe-56dd-4c0e-b36b-a82768b0aa29@gmail.com> (raw)
In-Reply-To: <20250626172159.87204-1-carenas@gmail.com>
Hi Carlo
On 26/06/2025 18:21, Carlo Marcelo Arenas Belón wrote:
> Since df076bdbcc ([PATCH] GIT: Listen on IPv6 as well, if available.,
> 2005-07-23), the original error checking was included in an inner loop
> unchanged, where its effect was different.
>
> Instead of retrying, after a EINTR during accept() in the listening
> socket, it will advance to the next one and try with that instead,
> leaving the client waiting for another round.
>
> Make sure that the loop doesn't advance
That makes sense
> and while at it, make sure
> that any possible completed children get reaped earlier.
What's the rationale for that? It means we end up calling
reap_dead_children() twice which sounds inefficient. If it is important
then I'm also struggling to see how it fits in with the proposal to use
SA_RESTART
> To avoid an
> unlikely busy loop, fallback to the old behaviour after a couple
> of attempts.
>
> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail•com>
> ---
> daemon.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/daemon.c b/daemon.c
> index d1be61fd57..f113839781 100644
> --- a/daemon.c
> +++ b/daemon.c
> @@ -1145,6 +1145,7 @@ static int service_loop(struct socketlist *socklist)
>
> for (size_t i = 0; i < socklist->nr; i++) {
> if (pfd[i].revents & POLLIN) {
> + int incoming;
> union {
> struct sockaddr sa;
> struct sockaddr_in sai;
> @@ -1153,11 +1154,19 @@ static int service_loop(struct socketlist *socklist)
> #endif
> } ss;
> socklen_t sslen = sizeof(ss);
> - int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
Why is the declaration of incoming moved but retry is declared here?
Thanks
Phillip
> + int retry = 3;
> +
> + redo:
> + incoming = accept(pfd[i].fd, &ss.sa, &sslen);
> if (incoming < 0) {
> switch (errno) {
> - case EAGAIN:
> case EINTR:
> + if (--retry) {
> + check_dead_children();
> + goto redo;
> + }
> + /* fallthrough */
> + case EAGAIN:
> case ECONNABORTED:
> continue;
> default:
next prev parent reply other threads:[~2025-06-27 8:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-26 16:10 [PATCH] daemon: correctly handle soft accept() errors Carlo Marcelo Arenas Belón
2025-06-26 16:15 ` Kristoffer Haugsbakk
2025-06-26 17:21 ` [PATCH v2] daemon: correctly handle soft accept() errors in service_loop Carlo Marcelo Arenas Belón
2025-06-27 8:38 ` Phillip Wood [this message]
2025-06-27 19:05 ` Carlo Marcelo Arenas Belón
2025-06-27 20:19 ` Junio C Hamano
2025-06-27 23:05 ` Carlo Marcelo Arenas Belón
2025-06-27 23:25 ` Hridoy Ahmed
2025-06-27 23:53 ` Junio C Hamano
2025-06-30 8:59 ` Phillip Wood
2025-06-27 23:14 ` [PATCH v3] " Carlo Marcelo Arenas Belón
2025-06-30 9:00 ` Phillip Wood
2025-06-30 15:33 ` Junio C Hamano
2025-07-01 19:33 ` Phillip Wood
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