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 089304FC8FF; Mon, 31 Aug 2026 13:41:33 +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=1788183695; cv=none; b=rqvWlnpFjykNcgDeynR3XlfKdeCrLaMYcgE8q/7+AA3iS7z6GtljZxhhv+DQf3KQ9Vr9RvXAbM7DqhPjr4YB9wj3lcaax579zi1UHHOoZDDnP5pG0gKajLPIKRa8pUYPR24sPrxJ7f8bhj5nPPyAKtLjRN5VEvXDH/Eg+7EaLt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183695; c=relaxed/simple; bh=+YAD5OjFnFye6nrKqNVp283zzmWnDPvXMARL+9eF1zY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LLwbcoudDoR/5cbgakIfQH2+FCds7PvPvIc2y9sGsRy73hrEAfanGNcCsluiEIu6X9PxgTiXf22zHGj0DRy71ya0dkCEGk30FOpJz8uMHoxN4DYNBP8qpg96ra6RwwL4KOJ+Atm1mJIRC+6bGpojtlnAGWQTtjR1oi08zkJxBtM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DNzcebOZ; 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="DNzcebOZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7ADCD1F00A3E; Mon, 31 Aug 2026 13:41:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788183692; bh=LhuCyi588EnORNxJAkDbj0Bd3XdNav3hGk3E+pQ3P34=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DNzcebOZXuR/eK8/3RwSmC++dnlCgfnN02PNBqwHKE8TJbmueq7gfkjY8FVkJxwZd qgUFtyDsZ1DjwEpel9kD4rUy2LTMe1wR6Ixb6eu4lw6LDctMIxo4NxV+XGdv5AfPLr LR/us6PSQy0ASQT6oiH0N18oLb3gLNRF8NRz0ZHA965hqj9gWBL/6Ia6xfDDAT/evy YKaufuLeHyhHoBCxlOPnAGE05y/UWKQRW6H+N2DWQysCLJw72Tfdy1wzyx/wdLhO/Y HQXIwNW2kk0aT6q6JoKVa9FyReX1BABnHEHBeGxCrsxuWcLuFOYsqfJc3YaJRRamET d3jb4xKnbXboQ== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Jiayuan Chen , syzbot+fbf3648ae7f5bdb05c59@syzkaller.appspotmail.com, Allison Henderson , Jakub Kicinski , Sasha Levin , davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.18-5.10] rds: annotate data-race around rs_seen_congestion Date: Mon, 31 Aug 2026 09:24:36 -0400 Message-ID: <20260831133314.4125787-248-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260831133314.4125787-1-sashal@kernel.org> References: <20260831133314.4125787-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.18.48 Content-Transfer-Encoding: 8bit From: Jiayuan Chen [ Upstream commit 67636cab273ed0c0b0f2adab6c9369a471cb7966 ] 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. Reported-by: syzbot+fbf3648ae7f5bdb05c59@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6a0f8d94.050a0220.6b33c.0000.GAE@google.com/ Signed-off-by: Jiayuan Chen Reviewed-by: Allison Henderson   Tested-by: Allison Henderson Link: https://patch.msgid.link/20260522011621.304470-1-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: The backport check finished: prepared stable commit `95ef1f3da4846` (upstream `67636cab273ed`) exists on the `autosel` branch but is not in current HEAD (`v6.18.44`), where the unannotated `rs_seen_congestion` accesses are still present. That supports the **YES** backport recommendation. net/rds/af_rds.c | 4 ++-- net/rds/send.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c index cc3a898bf5d51..a9445937d225b 100644 --- a/net/rds/af_rds.c +++ b/net/rds/af_rds.c @@ -217,7 +217,7 @@ static __poll_t rds_poll(struct file *file, struct socket *sock, poll_wait(file, sk_sleep(sk), wait); - if (rs->rs_seen_congestion) + if (READ_ONCE(rs->rs_seen_congestion)) poll_wait(file, &rds_poll_waitq, wait); read_lock_irqsave(&rs->rs_recv_lock, flags); @@ -245,7 +245,7 @@ static __poll_t rds_poll(struct file *file, struct socket *sock, /* clear state any time we wake a seen-congested socket */ if (mask) - rs->rs_seen_congestion = 0; + WRITE_ONCE(rs->rs_seen_congestion, 0); return mask; } diff --git a/net/rds/send.c b/net/rds/send.c index 071c5dca969a2..d474c9cda65ae 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -1339,7 +1339,7 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len) ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs); if (ret) { - rs->rs_seen_congestion = 1; + WRITE_ONCE(rs->rs_seen_congestion, 1); goto out; } while (!rds_send_queue_rm(rs, conn, cpath, rm, rs->rs_bound_port, -- 2.53.0