[dm-devel] Patch "dm: make sure create and remove dm device won't race with open and close table" has been added to the 6.1-stable tree

[Sasha Levin]

This is a note to let you know that I've just added the patch titled

    dm: make sure create and remove dm device won't race with open and close table

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     dm-make-sure-create-and-remove-dm-device-won-t-race-.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.



commit c54c815ac3d64cd35fc10e8eff95deda62b154e4
Author: Yu Kuai <yukuai3 at huawei.com>
Date:   Tue Nov 15 22:10:49 2022 +0800

    dm: make sure create and remove dm device won't race with open and close table
    
    [ Upstream commit d563792c8933a810d28ce0f2831f0726c2b15a31 ]
    
    open_table_device() and close_table_device() is protected by
    table_devices_lock, hence use it to protect add_disk() and
    del_gendisk().
    
    Prepare to track per-add_disk holder relations in dm.
    
    Signed-off-by: Yu Kuai <yukuai3 at huawei.com>
    Reviewed-by: Mike Snitzer <snitzer at kernel.org>
    Reviewed-by: Christoph Hellwig <hch at lst.de>
    Link: https://lore.kernel.org/r/20221115141054.1051801-6-yukuai1@huaweicloud.com
    Signed-off-by: Jens Axboe <axboe at kernel.dk>
    Stable-dep-of: 1a581b721699 ("dm: track per-add_disk holder relations in DM")
    Signed-off-by: Sasha Levin <sashal at kernel.org>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8fb0b97b2df1..f10ac680cef4 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1965,7 +1965,14 @@ static void cleanup_mapped_device(struct mapped_device *md)
 		spin_unlock(&_minor_lock);
 		if (dm_get_md_type(md) != DM_TYPE_NONE) {
 			dm_sysfs_exit(md);
+
+			/*
+			 * Hold lock to make sure del_gendisk() won't concurrent
+			 * with open/close_table_device().
+			 */
+			mutex_lock(&md->table_devices_lock);
 			del_gendisk(md->disk);
+			mutex_unlock(&md->table_devices_lock);
 		}
 		dm_queue_destroy_crypto_profile(md->queue);
 		put_disk(md->disk);
@@ -2325,15 +2332,24 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
 	if (r)
 		return r;
 
+	/*
+	 * Hold lock to make sure add_disk() and del_gendisk() won't concurrent
+	 * with open_table_device() and close_table_device().
+	 */
+	mutex_lock(&md->table_devices_lock);
 	r = add_disk(md->disk);
+	mutex_unlock(&md->table_devices_lock);
 	if (r)
 		return r;
 
 	r = dm_sysfs_init(md);
 	if (r) {
+		mutex_lock(&md->table_devices_lock);
 		del_gendisk(md->disk);
+		mutex_unlock(&md->table_devices_lock);
 		return r;
 	}
+
 	md->type = type;
 	return 0;
 }