Hello Luis,

Can you test the following patch and see if the issue can be addressed?

Please see the idea from the inline comment.

Also zram_index_mutex isn't needed in zram disk's store() compared with
your patch, then the deadlock issue you are addressing in this series can
be avoided.

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index fcaf2750f68f..3c17927d23a7 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c

@@ -1985,11 +1985,17 @@ static int zram_remove(struct zram *zram)
 
 	/* Make sure all the pending I/O are finished */
 	fsync_bdev(bdev);
-	zram_reset_device(zram);
 
 	pr_info("Removed device: %s\n", zram->disk->disk_name);
 
 	del_gendisk(zram->disk);
+
+	/*
+	 * reset device after gendisk is removed, so any change from sysfs
+	 * store won't come in, then we can really reset device here
+	 */
+	zram_reset_device(zram);
+
 	blk_cleanup_disk(zram->disk);
 	kfree(zram);
 	return 0;

@@ -2073,7 +2079,12 @@ static int zram_remove_cb(int id, void *ptr, void *data)
 static void destroy_devices(void)
 {
 	class_unregister(&zram_control_class);
+
+	/* hold the global lock so new device can't be added */
+	mutex_lock(&zram_index_mutex);
 	idr_for_each(&zram_index_idr, &zram_remove_cb, NULL);
+	mutex_unlock(&zram_index_mutex);
+