From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1859F2E5B2A; Mon, 1 Dec 2025 11:29:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764588561; cv=none; b=fhLO07FPXPXn8dzCcooZpAnwyXqOsoPSwu10++mhM9vuVdHfpN3zf5CJNXpwb031E/GDLEbrVn7UscD6Y0Typv39vXuYIBVDozcAhnRyScRGfveCNNPlbKUV/LxMPZX6+uQ6YO4IOBGDOzs3MkFwBUlYFzZEHKez0BFr5CJnR44= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764588561; c=relaxed/simple; bh=LptRPwXDFU5ZcLVXH/prHqJ7a6OVFqnUtMRJn9NADZQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=s+W3F3pweQoiMVKBO8vVQ3ZQZsyW16Z+co/9hh8rsWwA+a2gx+zzdFO/BV4pALjvuflWmhWvnqhGlb4bsaN6Y3JvpzwPP12XoU+KmqLuANE2jWeEMWKcAP+PaunZ2zuMpdrpKLX9vn8MNlfMXUJJ1gdPfpdhFNa7zxCM/BscM34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=e4OsTNBO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="e4OsTNBO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 931E1C4CEF1; Mon, 1 Dec 2025 11:29:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1764588561; bh=LptRPwXDFU5ZcLVXH/prHqJ7a6OVFqnUtMRJn9NADZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e4OsTNBO5vWeTGVB5VxQA4A08mDyp1UCAtZvDboksVUaOWRI3EuDM2n+dp7nPgQrH efJUe0RnYQQ1cyxwlTz6JmXV5cK3k6mtEaqHS2VOFZ2QxMSg/C+DBCdBOhbDXv7WZj XzTpOzkf/3huVDsuDdoPyNNJVxOp1y4g4l4/U7+4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Willem de Bruijn , David Ahern , Kuniyuki Iwashima , Jakub Kicinski , Paolo Abeni , Sasha Levin Subject: [PATCH 5.4 092/187] ipv6: np->rxpmtu race annotation Date: Mon, 1 Dec 2025 12:23:20 +0100 Message-ID: <20251201112244.566399695@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251201112241.242614045@linuxfoundation.org> References: <20251201112241.242614045@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 9fba1eb39e2f74d2002c5cbcf1d4435d37a4f752 ] Add READ_ONCE() annotations because np->rxpmtu can be changed while udpv6_recvmsg() and rawv6_recvmsg() read it. Since this is a very rarely used feature, and that udpv6_recvmsg() and rawv6_recvmsg() read np->rxopt anyway, change the test order so that np->rxpmtu does not need to be in a hot cache line. Signed-off-by: Eric Dumazet Reviewed-by: Willem de Bruijn Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250916160951.541279-4-edumazet@google.com Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/ipv6/raw.c | 2 +- net/ipv6/udp.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 731485b18de31..90d828c98b736 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -474,7 +474,7 @@ static int rawv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, if (flags & MSG_ERRQUEUE) return ipv6_recv_error(sk, msg, len, addr_len); - if (np->rxpmtu && np->rxopt.bits.rxpmtu) + if (np->rxopt.bits.rxpmtu && READ_ONCE(np->rxpmtu)) return ipv6_recv_rxpmtu(sk, msg, len, addr_len); skb = skb_recv_datagram(sk, flags, noblock, &err); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index db948e3a9bdc8..3ed835b308044 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -297,7 +297,7 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, if (flags & MSG_ERRQUEUE) return ipv6_recv_error(sk, msg, len, addr_len); - if (np->rxpmtu && np->rxopt.bits.rxpmtu) + if (np->rxopt.bits.rxpmtu && READ_ONCE(np->rxpmtu)) return ipv6_recv_rxpmtu(sk, msg, len, addr_len); try_again: -- 2.51.0