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 C4DFECCA48F for ; Tue, 7 Jun 2022 18:58:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352403AbiFGS6E (ORCPT ); Tue, 7 Jun 2022 14:58:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353329AbiFGSx6 (ORCPT ); Tue, 7 Jun 2022 14:53:58 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A8224D60C; Tue, 7 Jun 2022 11:03:45 -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 ams.source.kernel.org (Postfix) with ESMTPS id B36E6B81F38; Tue, 7 Jun 2022 18:03:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 265D1C34115; Tue, 7 Jun 2022 18:03:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654625022; bh=m8YR4hs10GdxwJtjOEPjX1uSm/XaYofzI1chRuCRg+0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B+ilj6fKLIJfuI4TMHYp/Q49ovLeKk5RN5Riq67iEI1emyXG/ImnBUtV1FFipshdH gilE7bG4vZD19mOVJfHBQSiCE/kSoCHJgrNw1+qeMmjQmFnSaN28xFid91f7ebN23b ag25snWzMYxnyF8zny03RtjjScEm6nJmSjcerLQM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "yukuai (C)" , Jan Kara , Christoph Hellwig , Jens Axboe Subject: [PATCH 5.15 539/667] bfq: Make sure bfqg for which we are queueing requests is online Date: Tue, 7 Jun 2022 19:03:24 +0200 Message-Id: <20220607164950.866371326@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607164934.766888869@linuxfoundation.org> References: <20220607164934.766888869@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: stable@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 @@ -610,10 +610,19 @@ 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; } /**