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 AF179C433EF for ; Mon, 13 Dec 2021 09:45:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235042AbhLMJps (ORCPT ); Mon, 13 Dec 2021 04:45:48 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:35898 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233110AbhLMJlq (ORCPT ); Mon, 13 Dec 2021 04:41:46 -0500 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 A81AFCE0AE2; Mon, 13 Dec 2021 09:41:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 580D4C00446; Mon, 13 Dec 2021 09:41:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1639388502; bh=OIUKyJEUh6kIs8eyaIGV9zHcxdJufY4CZ/RhKrc7iDc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DKCbbhkbMXxO4WA5jCYBxM5ijep++Q6jRDUmdcRvGxirl/afDcc6Z5iR9DHmKvDgL X0pkXbDKUds2Y/+swbWzh2/E/wTageHRpC5JCdUX3eyy6vC7kYakQa8z+/14W6OQCB Hrcz9qCUveJyTQUYfzQWkrrNzWL9LFlyqaoBqqM8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+37b8770e6d5a8220a039@syzkaller.appspotmail.com, Cong Wang , "David S. Miller" Subject: [PATCH 4.19 73/74] net_sched: fix a crash in tc_new_tfilter() Date: Mon, 13 Dec 2021 10:30:44 +0100 Message-Id: <20211213092933.255532366@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211213092930.763200615@linuxfoundation.org> References: <20211213092930.763200615@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: Cong Wang commit 460b360104d51552a57f39e54b2589c9fd7fa0b3 upstream. When tcf_block_find() fails, it already rollbacks the qdisc refcnt, so its caller doesn't need to clean up this again. Avoid calling qdisc_put() again by resetting qdisc to NULL for callers. Reported-by: syzbot+37b8770e6d5a8220a039@syzkaller.appspotmail.com Fixes: e368fdb61d8e ("net: sched: use Qdisc rcu API instead of relying on rtnl lock") Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/cls_api.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -629,8 +629,10 @@ static struct tcf_block *tcf_block_find( errout_rcu: rcu_read_unlock(); errout_qdisc: - if (*q) + if (*q) { qdisc_put(*q); + *q = NULL; + } return ERR_PTR(err); }