From patchwork Wed Jan 12 11:39:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 12711265 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 D4035C433F5 for ; Wed, 12 Jan 2022 11:39:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240119AbiALLje (ORCPT ); Wed, 12 Jan 2022 06:39:34 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:42136 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239872AbiALLjd (ORCPT ); Wed, 12 Jan 2022 06:39:33 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id B503C1F3BB; Wed, 12 Jan 2022 11:39:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1641987571; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Pcw0Dz6qCaXjfiGIwaXI/xy2ZlOMa2tLvBlwHG3TYvw=; b=onsstIQttVSLGgFpUSh3I8HnRDo/bROAbMlFewWB3U43RyYQ82nc4hoqFT161CX9+guIzd Jms7ILfI8Y+NMgyYLx5CBZ1R7c+WbgueYVfCUSF8y6x2PnhHAnf12bloWEKM45dWRHQhdX VXB4iTq5M+buNDopk2u4lDh9nWNytbw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1641987571; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Pcw0Dz6qCaXjfiGIwaXI/xy2ZlOMa2tLvBlwHG3TYvw=; b=qKNFZ6VjH57hsbem0RH8vQwYgBX3CXct42Clu9pZEGrwTOTZykyQM/60E9IMvf2k26d3+1 o8zALtEnkCuUtoCw== Received: from quack3.suse.cz (unknown [10.100.200.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id A1829A3B87; Wed, 12 Jan 2022 11:39:31 +0000 (UTC) Received: by quack3.suse.cz (Postfix, from userid 1000) id C1000A05E1; Wed, 12 Jan 2022 12:39:28 +0100 (CET) From: Jan Kara To: Cc: Jens Axboe , Paolo Valente , "yukuai (C)" , Jan Kara , stable@vger.kernel.org Subject: [PATCH 4/4] bfq: Update cgroup information before merging bio Date: Wed, 12 Jan 2022 12:39:22 +0100 Message-Id: <20220112113928.32349-4-jack@suse.cz> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220112113529.6355-1-jack@suse.cz> References: <20220112113529.6355-1-jack@suse.cz> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1409; h=from:subject; bh=P/+2SbEdiz2xvmkxw/cr+I4TuGV2AeuKw8OJviTNrjg=; b=owEBbQGS/pANAwAIAZydqgc/ZEDZAcsmYgBh3r3pQy/HX7G773Vd6m9ykG4cMcysm53jNa0NyqZ3 2jEOnyWJATMEAAEIAB0WIQSrWdEr1p4yirVVKBycnaoHP2RA2QUCYd696QAKCRCcnaoHP2RA2SMXB/ 9jRaHsj0cG/dgAOCCu6VA+421DnphVVT+iVOcNsSjpmRH7QvpRl58F+OkMmbSZDP1If4Xjl50txiIb 6RQqBlUkj95eBCT4ufcZlA1e/TGlVIvlB+MS9FGs/a9EYhe4vm4NUde+ihp2AfXGZCb1/v3UrcTHhu pS+DEv8gzxe+qpbvYfDf8Lt8fHyTDNibiYmgs1MqolBOYz9/65MVASylA+AuGLYMnhPpZhNnQ2ds6G efBH0ZiJG9zKeqmGHgirmbKoJqwEVeUWdh0JzKCPhITYMx/1e2esDgZp4aP9KO2VXAN//HibX3KxIY rZQlGH7YPWm42GtOMC7LtZNDbM67HD X-Developer-Key: i=jack@suse.cz; a=openpgp; fpr=93C6099A142276A28BBE35D815BC833443038D8C Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org When the process is migrated to a different cgroup (or in case of writeback just starts submitting bios associated with a different cgroup) bfq_merge_bio() can operate with stale cgroup information in bic. Thus the bio can be merged to a request from a different cgroup or it can result in merging of bfqqs for different cgroups or bfqqs of already dead cgroups and causing possible use-after-free issues. Fix the problem by updating cgroup information in bfq_merge_bio(). CC: stable@vger.kernel.org Fixes: e21b7a0b9887 ("block, bfq: add full hierarchical scheduling and cgroups support") Signed-off-by: Jan Kara --- block/bfq-iosched.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 361d321b012a..8a088d77a0b6 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -2337,10 +2337,17 @@ static bool bfq_bio_merge(struct request_queue *q, struct bio *bio, spin_lock_irq(&bfqd->lock); - if (bic) + if (bic) { + /* + * Make sure cgroup info is uptodate for current process before + * considering the merge. + */ + bfq_bic_update_cgroup(bic, bio); + bfqd->bio_bfqq = bic_to_bfqq(bic, op_is_sync(bio->bi_opf)); - else + } else { bfqd->bio_bfqq = NULL; + } bfqd->bio_bic = bic; ret = blk_mq_sched_try_merge(q, bio, nr_segs, &free);