From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6CD3F18658 for ; Wed, 20 Sep 2023 11:50:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E231EC433C9; Wed, 20 Sep 2023 11:50:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695210633; bh=6Me187LBX6tVZLiyjI1qt1aT7Yv/voj0s9wazCnAepQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kNmRxJQoqXbEz7fp27aqDjDmU8VBEkZzjGR6F+pYqc/bccjQ9ArfEQD6dHc3M7RDp 5Qh86wtZ9dKJsXC6FNJDmBN7Twkf3MJJ4kxxsEHY5Z/X7tNuh8DxKxKr6WB4Qm+7Lg ihugLierssE4V+joAD32IBe3zElgrSg00SWyfnK0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yu Kuai , Song Liu , Sasha Levin Subject: [PATCH 6.5 147/211] md: fix warning for holder mismatch from export_rdev() Date: Wed, 20 Sep 2023 13:29:51 +0200 Message-ID: <20230920112850.415621328@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112845.859868994@linuxfoundation.org> References: <20230920112845.859868994@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yu Kuai [ Upstream commit 99892147f028d711f9d40fefad4f33632593864c ] Commit a1d767191096 ("md: use mddev->external to select holder in export_rdev()") fix the problem that 'claim_rdev' is used for blkdev_get_by_dev() while 'rdev' is used for blkdev_put(). However, if mddev->external is changed from 0 to 1, then 'rdev' is used for blkdev_get_by_dev() while 'claim_rdev' is used for blkdev_put(). And this problem can be reporduced reliably by following: New file: mdadm/tests/23rdev-lifetime devname=${dev0##*/} devt=`cat /sys/block/$devname/dev` pid="" runtime=2 clean_up_test() { pill -9 $pid echo clear > /sys/block/md0/md/array_state } trap 'clean_up_test' EXIT add_by_sysfs() { while true; do echo $devt > /sys/block/md0/md/new_dev done } remove_by_sysfs(){ while true; do echo remove > /sys/block/md0/md/dev-${devname}/state done } echo md0 > /sys/module/md_mod/parameters/new_array || die "create md0 failed" add_by_sysfs & pid="$pid $!" remove_by_sysfs & pid="$pid $!" sleep $runtime exit 0 Test cmd: ./test --save-logs --logdir=/tmp/ --keep-going --dev=loop --tests=23rdev-lifetime Test result: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 960 at block/bdev.c:618 blkdev_put+0x27c/0x330 Modules linked in: multipath md_mod loop CPU: 0 PID: 960 Comm: test Not tainted 6.5.0-rc2-00121-g01e55c376936-dirty #50 RIP: 0010:blkdev_put+0x27c/0x330 Call Trace: export_rdev.isra.23+0x50/0xa0 [md_mod] mddev_unlock+0x19d/0x300 [md_mod] rdev_attr_store+0xec/0x190 [md_mod] sysfs_kf_write+0x52/0x70 kernfs_fop_write_iter+0x19a/0x2a0 vfs_write+0x3b5/0x770 ksys_write+0x74/0x150 __x64_sys_write+0x22/0x30 do_syscall_64+0x40/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fix the problem by recording if 'rdev' is used as holder. Fixes: a1d767191096 ("md: use mddev->external to select holder in export_rdev()") Signed-off-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230825025532.1523008-3-yukuai1@huaweicloud.com Signed-off-by: Sasha Levin --- drivers/md/md.c | 15 ++++++++++++--- drivers/md/md.h | 3 +++ 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index fba2809cd384a..06a8ccdb5135d 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2452,7 +2452,8 @@ static void export_rdev(struct md_rdev *rdev, struct mddev *mddev) if (test_bit(AutoDetected, &rdev->flags)) md_autodetect_dev(rdev->bdev->bd_dev); #endif - blkdev_put(rdev->bdev, mddev->external ? &claim_rdev : rdev); + blkdev_put(rdev->bdev, + test_bit(Holder, &rdev->flags) ? rdev : &claim_rdev); rdev->bdev = NULL; kobject_put(&rdev->kobj); } @@ -3632,6 +3633,7 @@ EXPORT_SYMBOL_GPL(md_rdev_init); static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor) { struct md_rdev *rdev; + struct md_rdev *holder; sector_t size; int err; @@ -3646,8 +3648,15 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe if (err) goto out_clear_rdev; + if (super_format == -2) { + holder = &claim_rdev; + } else { + holder = rdev; + set_bit(Holder, &rdev->flags); + } + rdev->bdev = blkdev_get_by_dev(newdev, BLK_OPEN_READ | BLK_OPEN_WRITE, - super_format == -2 ? &claim_rdev : rdev, NULL); + holder, NULL); if (IS_ERR(rdev->bdev)) { pr_warn("md: could not open device unknown-block(%u,%u).\n", MAJOR(newdev), MINOR(newdev)); @@ -3684,7 +3693,7 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe return rdev; out_blkdev_put: - blkdev_put(rdev->bdev, super_format == -2 ? &claim_rdev : rdev); + blkdev_put(rdev->bdev, holder); out_clear_rdev: md_rdev_clear(rdev); out_free_rdev: diff --git a/drivers/md/md.h b/drivers/md/md.h index 1aef86bf3fc31..b0a0f5a5c7836 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -211,6 +211,9 @@ enum flag_bits { * check if there is collision between raid1 * serial bios. */ + Holder, /* rdev is used as holder while opening + * underlying disk exclusively. + */ }; static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors, -- 2.40.1