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 8CCCE1C31 for ; Wed, 23 Nov 2022 09:57:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9CC3C433C1; Wed, 23 Nov 2022 09:57:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669197475; bh=fvi7DgZsAFoziIzV1E5G1QMyu9rduF3TerUbwBtOGFI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JMhpH+de8R/fbUILrYW9ZLjWT4PPufnEG3SQeR94nBducGRDlbHPbFQ8NSrWBaPOB 9KHR47M8kB93G/BJ6ffyhsX+o/r3Yq9W7XnBGBOYMpqHt4zzTy29j2QPfrmvA6Wvds henOofR4CEWFPVeV9m5t/eaSFAQjOjn0DXuAmSw4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gerald Schaefer , Heiko Carstens , Alexander Gordeev Subject: [PATCH 6.0 274/314] s390/dcssblk: fix deadlock when adding a DCSS Date: Wed, 23 Nov 2022 09:51:59 +0100 Message-Id: <20221123084637.952977398@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084625.457073469@linuxfoundation.org> References: <20221123084625.457073469@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Gerald Schaefer commit a41a11b4009580edb6e2b4c76e5e2ee303f87157 upstream. After the rework from commit 1ebe2e5f9d68 ("block: remove GENHD_FL_EXT_DEVT"), when calling device_add_disk(), dcssblk will end up in disk_scan_partitions(), and not break out early w/o GENHD_FL_NO_PART. This will trigger implicit open/release via blkdev_get/put_whole() later. dcssblk_release() will then deadlock on dcssblk_devices_sem semaphore, which is already held from dcssblk_add_store() when calling device_add_disk(). dcssblk does not support partitions (DCSSBLK_MINORS_PER_DISK == 1), and never scanned partitions before. Therefore restore the previous behavior, and explicitly disallow partition scanning by setting the GENHD_FL_NO_PART flag. This will also prevent this deadlock scenario. Fixes: 1ebe2e5f9d68 ("block: remove GENHD_FL_EXT_DEVT") Cc: # 5.17+ Signed-off-by: Gerald Schaefer Acked-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Greg Kroah-Hartman --- drivers/s390/block/dcssblk.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index 93b80da60277..b392b9f5482e 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -636,6 +636,7 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char dev_info->gd->minors = DCSSBLK_MINORS_PER_DISK; dev_info->gd->fops = &dcssblk_devops; dev_info->gd->private_data = dev_info; + dev_info->gd->flags |= GENHD_FL_NO_PART; blk_queue_logical_block_size(dev_info->gd->queue, 4096); blk_queue_flag_set(QUEUE_FLAG_DAX, dev_info->gd->queue); -- 2.38.1