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 A296BC43219 for ; Tue, 10 May 2022 14:04:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244995AbiEJOIb (ORCPT ); Tue, 10 May 2022 10:08:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244693AbiEJNq4 (ORCPT ); Tue, 10 May 2022 09:46:56 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B7FB173350; Tue, 10 May 2022 06:31:54 -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 sin.source.kernel.org (Postfix) with ESMTPS id 5EF75CE1EF7; Tue, 10 May 2022 13:31:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 781F2C385A6; Tue, 10 May 2022 13:31:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652189510; bh=p3x2/3akNAtRt+p0xbegcWAmT13/WUYjwP+8L5oj3zY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Uryts6qXQvzgZh87+F/ZncU6pi8069Dj62VnV9qf85UFDekmLLexqbRBOgR5+W1k3 uk7R4Qp2za7fowvg3OwtxkZMueW6tGKKzoXoLwLqZ+UkrVoxaFjZAIFkJzOc9CibwL vRizHbtFUPPPMkYvFfqdj+bOOp/hf3xNrbzJgA98= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Taehee Yoo , "David S. Miller" Subject: [PATCH 5.15 073/135] mld: respect RCU rules in ip6_mc_source() and ip6_mc_msfilter() Date: Tue, 10 May 2022 15:07:35 +0200 Message-Id: <20220510130742.506192143@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220510130740.392653815@linuxfoundation.org> References: <20220510130740.392653815@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: Eric Dumazet commit a9384a4c1d250cb40cebf50e41459426d160b08e upstream. Whenever RCU protected list replaces an object, the pointer to the new object needs to be updated _before_ the call to kfree_rcu() or call_rcu() Also ip6_mc_msfilter() needs to update the pointer before releasing the mc_lock mutex. Note that linux-5.13 was supporting kfree_rcu(NULL, rcu), so this fix does not need the conditional test I was forced to use in the equivalent patch for IPv4. Fixes: 882ba1f73c06 ("mld: convert ipv6_mc_socklist->sflist to RCU") Signed-off-by: Eric Dumazet Cc: Taehee Yoo Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/mcast.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 909f937befd7..7f695c39d9a8 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -460,10 +460,10 @@ int ip6_mc_source(int add, int omode, struct sock *sk, newpsl->sl_addr[i] = psl->sl_addr[i]; atomic_sub(struct_size(psl, sl_addr, psl->sl_max), &sk->sk_omem_alloc); - kfree_rcu(psl, rcu); } + rcu_assign_pointer(pmc->sflist, newpsl); + kfree_rcu(psl, rcu); psl = newpsl; - rcu_assign_pointer(pmc->sflist, psl); } rv = 1; /* > 0 for insert logic below if sl_count is 0 */ for (i = 0; i < psl->sl_count; i++) { @@ -565,12 +565,12 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf, psl->sl_count, psl->sl_addr, 0); atomic_sub(struct_size(psl, sl_addr, psl->sl_max), &sk->sk_omem_alloc); - kfree_rcu(psl, rcu); } else { ip6_mc_del_src(idev, group, pmc->sfmode, 0, NULL, 0); } - mutex_unlock(&idev->mc_lock); rcu_assign_pointer(pmc->sflist, newpsl); + mutex_unlock(&idev->mc_lock); + kfree_rcu(psl, rcu); pmc->sfmode = gsf->gf_fmode; err = 0; done: -- 2.36.1