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 620D725DCE5; Tue, 11 Mar 2025 15:13:07 +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=1741705987; cv=none; b=uT84VPih9OYt0NrUE5BeaW39Rm1Itpgbu/sM7eU3IqHrgHFd1c6zEn4raf94fH4RDEZDoU8jaEOGobd5C+MOpx4uAedneIM7NgAQJD1s9niEl4Mq3pJWFk2+UxLfDYS5jZ+xt0hpWZCjOkxuI38gNKSt8K1zeYm3oiKczDuudlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741705987; c=relaxed/simple; bh=lpx7osaaPRWZSbA1GdAMYTpRo0T8qjgGrSmWSDDIH8c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oiUBlvzSGsqMnkoq/oShGSTYQ8SJ/xBKPC3QKfDueVNRTGeBH1/oYKJkNdpC0L2M/xkivnLKkrD1mlPtems5CcEdtfIdsbJgIE1+4wuXeLb6IWRy7W4Uh5XWBv21ihr4qmFegwDQsbVudkxEkn6O67pUFCm3mWWDKhNtKxBLEjk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=o+W7XSky; 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="o+W7XSky" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA520C4CEE9; Tue, 11 Mar 2025 15:13:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741705987; bh=lpx7osaaPRWZSbA1GdAMYTpRo0T8qjgGrSmWSDDIH8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o+W7XSkyYg+0jf1LpbwGuL5uW+roLcZgdKqRfQKzVOxmQEJWYUSOuD06cxsmCv4UK M/rkYNLFVM4fz+P/X3a93p426Dt6Yg/I91SJXawZjJmJAui2wwRmuSmIxFTmrwQocH DUo3Tf5mUSMKRPaVXQNZvz+H4+idi16wZFaMpl3A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 205/328] ipv6: use RCU protection in ip6_default_advmss() Date: Tue, 11 Mar 2025 15:59:35 +0100 Message-ID: <20250311145723.056258655@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250311145714.865727435@linuxfoundation.org> References: <20250311145714.865727435@linuxfoundation.org> User-Agent: quilt/0.68 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 3c8ffcd248da34fc41e52a46e51505900115fc2a ] ip6_default_advmss() needs rcu protection to make sure the net structure it reads does not disappear. Fixes: 5578689a4e3c ("[NETNS][IPV6] route6 - make route6 per namespace") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250205155120.1676781-11-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/route.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 364abcf4b6c14..99908861246d3 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -3090,13 +3090,18 @@ static unsigned int ip6_default_advmss(const struct dst_entry *dst) { struct net_device *dev = dst->dev; unsigned int mtu = dst_mtu(dst); - struct net *net = dev_net(dev); + struct net *net; mtu -= sizeof(struct ipv6hdr) + sizeof(struct tcphdr); + rcu_read_lock(); + + net = dev_net_rcu(dev); if (mtu < net->ipv6.sysctl.ip6_rt_min_advmss) mtu = net->ipv6.sysctl.ip6_rt_min_advmss; + rcu_read_unlock(); + /* * Maximal non-jumbo IPv6 payload is IPV6_MAXPLEN and * corresponding MSS is IPV6_MAXPLEN - tcp_header_size. -- 2.39.5