From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2A7DC19F28 for ; Wed, 27 Jul 2022 16:35:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238014AbiG0QfK (ORCPT ); Wed, 27 Jul 2022 12:35:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237868AbiG0Qdp (ORCPT ); Wed, 27 Jul 2022 12:33:45 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE66A474CB; Wed, 27 Jul 2022 09:26:45 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 92537619F4; Wed, 27 Jul 2022 16:26:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C047C433D6; Wed, 27 Jul 2022 16:26:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939204; bh=W0q27RSXpDQKArdu1Qarm0cHko2rXjDyC3znbuUCfFE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D1/NTL4UUMpSqRBwB6b6Pc2GU/jL9jxLcEQp74oQCU16+wCRTt5V3qxqFicxvCDIj yEAkFlo1ukjIgNVhNjDYTnZAVAEhQ8NXpZO0nB6BbWe8PH3AWtxw7xqio//hf0yVA4 CCpu7MjshLMfgoVVVWM3/KZDpvCGw4p3o2PMstM8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 18/62] igmp: Fix a data-race around sysctl_igmp_max_memberships. Date: Wed, 27 Jul 2022 18:10:27 +0200 Message-Id: <20220727161004.910586609@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161004.175638564@linuxfoundation.org> References: <20220727161004.175638564@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuniyuki Iwashima [ Upstream commit 6305d821e3b9b5379d348528e5b5faf316383bc2 ] While reading sysctl_igmp_max_memberships, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/igmp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 957e1170a8a3..b831825f234f 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2212,7 +2212,7 @@ static int __ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr, count++; } err = -ENOBUFS; - if (count >= net->ipv4.sysctl_igmp_max_memberships) + if (count >= READ_ONCE(net->ipv4.sysctl_igmp_max_memberships)) goto done; iml = sock_kmalloc(sk, sizeof(*iml), GFP_KERNEL); if (!iml) -- 2.35.1