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 2F9FE2820A0; Tue, 11 Nov 2025 01:34:20 +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=1762824860; cv=none; b=dpR43Bu+ylWY1CKkFK5gCoheEF2CpAeeuTLznBo4LbusPZ7TtIP7/Wtww8vS1cXFACmkrL6mHvrWlHqkrEbXmZtRvlPXiQo9NV74abRYO7BQadLtA/4CghxtivxXdJqjIYEYDECJnAaZf4oA4+1h1TfWA4G0rr8OqfaMnchXKKg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762824860; c=relaxed/simple; bh=Q0mmcAp9ukSV7Y6o22jj2iCxpP+FsTWj1Zfl9FYzTDs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Gm3Jb7ezktyXxjIDI4FPcbrPS1rwKGxWb0N5Fu36kCdQZKb/pUvZiuT7GX9jy0TzNDjpmCmIB4Duecp+2nhpAvubtYjWRZZRW60EgM12kIoLXwX2EWEM7HcWUDp7/AOlbOPxU8ahHU2t2iczulor7VG4Y8zYmABtvo5dYAKIs1w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TkSP8aDK; 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="TkSP8aDK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C19C8C116B1; Tue, 11 Nov 2025 01:34:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1762824860; bh=Q0mmcAp9ukSV7Y6o22jj2iCxpP+FsTWj1Zfl9FYzTDs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TkSP8aDK5+xi4ab1Mp27/HMvi/GVi74YHTN8BNaHuKXL2t1j3H6USeL/sBCnNof8u vQ3C4P40QDw8lO27ZblcR9JdhY9DIpS2kL7DRpWdCd+tqAP8uLr1fWXu5mcuDWzKtp hpKmx4wISvMaHpoEYn4ARD8rAsnc3qd6Qma3I5rA= 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 6.17 586/849] ipv6: np->rxpmtu race annotation Date: Tue, 11 Nov 2025 09:42:36 +0900 Message-ID: <20251111004550.590768869@linuxfoundation.org> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20251111004536.460310036@linuxfoundation.org> References: <20251111004536.460310036@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 6.17-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 4c3f8245c40f1..eceef8af1355f 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -445,7 +445,7 @@ 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, &err); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 6a68f77da44b5..7f53fcc82a9ec 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -479,7 +479,7 @@ 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