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authorGerald Schaefer <gerald.schaefer@linux.ibm.com>2022-10-27 17:19:38 +0300
committerAlexander Gordeev <agordeev@linux.ibm.com>2022-11-16 13:39:11 +0300
commita41a11b4009580edb6e2b4c76e5e2ee303f87157 (patch)
treece68fae9954386e4727b35ae45ddc8e12b3cbeea
parent30d17fac6aaedb40d111bb159f4b35525637ea78 (diff)
downloadlinux-a41a11b4009580edb6e2b4c76e5e2ee303f87157.tar.xz
s390/dcssblk: fix deadlock when adding a DCSS
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: <stable@vger.kernel.org> # 5.17+ Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
-rw-r--r--drivers/s390/block/dcssblk.c1
1 files changed, 1 insertions, 0 deletions
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);