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 EF4D8C433EF for ; Tue, 7 Jun 2022 18:12:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349777AbiFGSM3 (ORCPT ); Tue, 7 Jun 2022 14:12:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349826AbiFGRvi (ORCPT ); Tue, 7 Jun 2022 13:51:38 -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 EEBAC252A6; Tue, 7 Jun 2022 10:39:01 -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 9BC2A615B1; Tue, 7 Jun 2022 17:38:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A938AC385A5; Tue, 7 Jun 2022 17:38:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654623514; bh=sgoGiyinGfGFOR0BlmGTWzl4IdhgAVwAoae3GDkUjaA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xufLw3XO2GXjwTMwpz8F8b0A0fohZ9pmnLrOhKnPpCYrnB5pj7odbY9mCcZtBdtRa VYs3xnvq2PAZSQdC6w0UZxfzyyU44Z9VJl1HHPIg6YNCLWpaChjQLbSCJA9saR5VZZ g4+EbivJdmXTJNJAtbMy6uNDUnSTGZvpNN8wucKY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , "yukuai (C)" , Jan Kara , Christoph Hellwig , Jens Axboe Subject: [PATCH 5.10 445/452] bfq: Make sure bfqg for which we are queueing requests is online Date: Tue, 7 Jun 2022 19:05:02 +0200 Message-Id: <20220607164921.830400796@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607164908.521895282@linuxfoundation.org> References: <20220607164908.521895282@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: Jan Kara commit 075a53b78b815301f8d3dd1ee2cd99554e34f0dd upstream. Bios queued into BFQ IO scheduler can be associated with a cgroup that was already offlined. This may then cause insertion of this bfq_group into a service tree. But this bfq_group will get freed as soon as last bio associated with it is completed leading to use after free issues for service tree users. Fix the problem by making sure we always operate on online bfq_group. If the bfq_group associated with the bio is not online, we pick the first online parent. CC: stable@vger.kernel.org Fixes: e21b7a0b9887 ("block, bfq: add full hierarchical scheduling and cgroups support") Tested-by: "yukuai (C)" Signed-off-by: Jan Kara Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220401102752.8599-9-jack@suse.cz Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/bfq-cgroup.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -608,10 +608,19 @@ static void bfq_link_bfqg(struct bfq_dat struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio) { struct blkcg_gq *blkg = bio->bi_blkg; + struct bfq_group *bfqg; - if (!blkg) - return bfqd->root_group; - return blkg_to_bfqg(blkg); + while (blkg) { + bfqg = blkg_to_bfqg(blkg); + if (bfqg->online) { + bio_associate_blkg_from_css(bio, &blkg->blkcg->css); + return bfqg; + } + blkg = blkg->parent; + } + bio_associate_blkg_from_css(bio, + &bfqg_to_blkg(bfqd->root_group)->blkcg->css); + return bfqd->root_group; } /**