From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A8D8029B77C; Fri, 22 May 2026 04:49:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779425363; cv=none; b=hp2Rs8Vhunv5E4BoRDmi+IN7Gielpgo6vq63nKX5KjzwpTj7kEqfyU+V0NiRvoDfi/Hb5M2sEAKpHlxcXD1x4++eimRPYDppO5uD88dmSANyzEIJLTDCZo0LsFUBTMiODycxNbTnjYp30mGixPjQV4h6duS2ta2rD1YC/jauJRc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779425363; c=relaxed/simple; bh=upzwlhH2S6BYm2RtVA6AYXk71GKmgyCd8tcanZx/Pjw=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=KF9fJ+HYlA5qdA5IQvTThHpCgRRjc2o7MVxHzLxSyq5O0nulYBWmc/5Fznez1GKpc9EHcGuQjlq1A1JG9gdlO0nndt6gA7jgQkRbCJfyCc4Lmgvp0f/WQKuoTnkMou2O6RhiNd7umEt7SKE5w+ybGj3KoG/mMV2Vx7YMAMOnHFw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LSiqZitO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LSiqZitO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C97921F00A3D; Fri, 22 May 2026 04:49:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779425360; bh=ekNjVBI3tkZHPdsUPq0t0Huu7boUNAOIWIJNJDXGevI=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=LSiqZitOmkNs6UcUnhE064EQY5fhVG3mtdt5yeq7FxnAYdYRe0eQmwG4yM7BByXha mn6RIXqMClMSMzRaQourcJQdg7CIUvlwl+0D5vVfyPJFDj4RsMYhU9CoTFm3Kpk+l3 rlcWQW4mj9rbb7AMsAmMaJKWcf6X4AlYeiLt/YPoWwjkvZnsrDabKT0AgCS/LnO6Ri qCHQc1E6/W16tYQWBj/OifEXR+npJ45LtZzfjvVqKoKIEgO32otPkld58OjWPPgfvS jAjoBtsDDg4XyxkTlmOzTVZUTP7pGYaqPWBJ5mqe7OkEi4SvS1gqe5iLmepzqCGGVQ 7I30KhK5FoxgA== Message-ID: Subject: Re: [PATCH net] rds: annotate data-race around rs_seen_congestion From: Allison Henderson To: Jiayuan Chen , netdev@vger.kernel.org Cc: syzbot+fbf3648ae7f5bdb05c59@syzkaller.appspotmail.com, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Andy Grover , linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org Date: Thu, 21 May 2026 21:49:19 -0700 In-Reply-To: <20260522011621.304470-1-jiayuan.chen@linux.dev> References: <20260522011621.304470-1-jiayuan.chen@linux.dev> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.3-0ubuntu1.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2026-05-22 at 09:16 +0800, Jiayuan Chen wrote: > rs_seen_congestion is read in rds_poll() and written in rds_sendmsg() > and rds_poll() without any lock. Use READ_ONCE()/WRITE_ONCE() to > annotate these lockless accesses and silence KCSAN. >=20 > Fixes: b98ba52f96e7 ("RDS: only put sockets that have seen congestion on = the poll_waitq") > Reported-by: syzbot+fbf3648ae7f5bdb05c59@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/netdev/6a0f8d94.050a0220.6b33c.0000.GAE@g= oogle.com/ > Signed-off-by: Jiayuan Chen Hi Jiayuan, I was about to send the same patch, so no complaints here. Thanks for catc= hing this. Reviewed-by: Allison Henderson =C2=A0 Tested-by: Allison Henderson Allison > --- > net/rds/af_rds.c | 4 ++-- > net/rds/send.c | 2 +- > 2 files changed, 3 insertions(+), 3 deletions(-) >=20 > diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c > index 76f625986a7f..93b2da63ed42 100644 > --- a/net/rds/af_rds.c > +++ b/net/rds/af_rds.c > @@ -219,7 +219,7 @@ static __poll_t rds_poll(struct file *file, struct so= cket *sock, > =20 > poll_wait(file, sk_sleep(sk), wait); > =20 > - if (rs->rs_seen_congestion) > + if (READ_ONCE(rs->rs_seen_congestion)) > poll_wait(file, &rds_poll_waitq, wait); > =20 > read_lock_irqsave(&rs->rs_recv_lock, flags); > @@ -247,7 +247,7 @@ static __poll_t rds_poll(struct file *file, struct so= cket *sock, > =20 > /* clear state any time we wake a seen-congested socket */ > if (mask) > - rs->rs_seen_congestion =3D 0; > + WRITE_ONCE(rs->rs_seen_congestion, 0); > =20 > return mask; > } > diff --git a/net/rds/send.c b/net/rds/send.c > index d8b14ff9d366..e5d58c29aabe 100644 > --- a/net/rds/send.c > +++ b/net/rds/send.c > @@ -1388,7 +1388,7 @@ int rds_sendmsg(struct socket *sock, struct msghdr = *msg, size_t payload_len) > =20 > ret =3D rds_cong_wait(conn->c_fcong, dport, nonblock, rs); > if (ret) { > - rs->rs_seen_congestion =3D 1; > + WRITE_ONCE(rs->rs_seen_congestion, 1); > goto out; > } > while (!rds_send_queue_rm(rs, conn, cpath, rm, rs->rs_bound_port,