From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) (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 2159D11CAF; Fri, 22 May 2026 01:17:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779412639; cv=none; b=HWGGE4ItcBP67LZJLrUrOxR5x19u0AOq/8VI2CMBseZF52XBxXi0sOvmUgJXxXdT+0nYXy8yz9HjahyXunGmPodWknFJCrVnKGhlAqSJhMxZUh6WBbjVtbsJaudksmJbESZnCmGOLe4zMQSCDbQzrcLoLDANfQpjJXq1Aqfx0oY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779412639; c=relaxed/simple; bh=8SDtOnmUdsIHETLv+JxXHaX2XfvnSGeokYjGqmuI6O4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=OgWnG1PGxrRo/zc8hC17p6MvfM/oxbpV6eQY32c96kq9UFCe3OD8/sXf6UimK6u61zRzRxyTRcpc/ncAQQ3Tc/Xv2nzt1dMJO2x3RnB4D0zMm+5GOCnclGXsYE5jC9qWoPS9aOfnRCDRWU3wEuztRadUNZw6bq6u9t6RNEThIJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=C+jTNclZ; arc=none smtp.client-ip=91.218.175.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="C+jTNclZ" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1779412634; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=IKJ+X1WNjuIEeqP8tG1jQwI+VA6DwxQun0tsoICkQG8=; b=C+jTNclZYDSG9TXOzP3At9TXYuQYkHD+rKJPiGxNUcGfHgeOLOvcBEG5UeI5au9MgtU0bV YwX2baOyfDD7j4g/OlHZZzKfsV+VzJ9Ynjd6+DtqBP4G96yuGoshGfT3tjxp8VXFH4BL/H 6NW/aH+Nv0ZVKKMYvvlOoO5FfK7k7rs= From: Jiayuan Chen To: netdev@vger.kernel.org Cc: Jiayuan Chen , syzbot+fbf3648ae7f5bdb05c59@syzkaller.appspotmail.com, Allison Henderson , "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 Subject: [PATCH net] rds: annotate data-race around rs_seen_congestion Date: Fri, 22 May 2026 09:16:20 +0800 Message-ID: <20260522011621.304470-1-jiayuan.chen@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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. 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@google.com/ Signed-off-by: Jiayuan Chen --- 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 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 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); @@ -247,7 +247,7 @@ 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 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) 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, -- 2.43.0