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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F264DC433F5 for ; Sat, 13 Nov 2021 14:20:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D900C60F44 for ; Sat, 13 Nov 2021 14:20:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235882AbhKMOXi (ORCPT ); Sat, 13 Nov 2021 09:23:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:42810 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231672AbhKMOXh (ORCPT ); Sat, 13 Nov 2021 09:23:37 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DA6C9611AE; Sat, 13 Nov 2021 14:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636813245; bh=ffGbg377uXgku1Cgt3w/yx/Z+/BbW5UIp9xHYGUPQcY=; h=Subject:To:Cc:From:Date:From; b=rU6HMh+0chGA2JfMZvtEbH2VbjectjIh8rqpuw8da9GK1+W5KRyzexYjzn7cDKcII JfcvChUq7vRFXO4wOThUDdtuSXsY3MVXY476LX6WbmY3I15n9L3qLqNcqMZaZLZs/c pxX3LOHDM0lczlYF5sQ2K+yDBYBUuZzzVm9k78gk= Subject: FAILED: patch "[PATCH] blk-cgroup: blk_cgroup_bio_start() should use irq-safe" failed to apply to 5.14-stable tree To: tj@kernel.org, axboe@kernel.dk Cc: From: Date: Sat, 13 Nov 2021 15:20:34 +0100 Message-ID: <163681323494123@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 3c08b0931eedd04c530040499fadeccab50ed646 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 14 Oct 2021 13:20:22 -1000 Subject: [PATCH] blk-cgroup: blk_cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu c3df5fb57fe8 ("cgroup: rstat: fix A-A deadlock on 32bit around u64_stats_sync") made u64_stats updates irq-safe to avoid A-A deadlocks. Unfortunately, the conversion missed one in blk_cgroup_bio_start(). Fix it. Fixes: 2d146aa3aa84 ("mm: memcontrol: switch to rstat") Cc: stable@vger.kernel.org # v5.13+ Reported-by: syzbot+9738c8815b375ce482a1@syzkaller.appspotmail.com Signed-off-by: Tejun Heo Link: https://lore.kernel.org/r/YWi7NrQdVlxD6J9W@slm.duckdns.org Signed-off-by: Jens Axboe diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 38b9f7684952..9a1c5839dd46 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1897,10 +1897,11 @@ void blk_cgroup_bio_start(struct bio *bio) { int rwd = blk_cgroup_io_type(bio), cpu; struct blkg_iostat_set *bis; + unsigned long flags; cpu = get_cpu(); bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); - u64_stats_update_begin(&bis->sync); + flags = u64_stats_update_begin_irqsave(&bis->sync); /* * If the bio is flagged with BIO_CGROUP_ACCT it means this is a split @@ -1912,7 +1913,7 @@ void blk_cgroup_bio_start(struct bio *bio) } bis->cur.ios[rwd]++; - u64_stats_update_end(&bis->sync); + u64_stats_update_end_irqrestore(&bis->sync, flags); if (cgroup_subsys_on_dfl(io_cgrp_subsys)) cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); put_cpu();