Patch "zram: fix uninitialized ZRAM not releasing backing device" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    zram: fix uninitialized ZRAM not releasing backing device

to the 5.15-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:
     zram-fix-uninitialized-zram-not-releasing-backing-de.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b6a138af7438a2eff9fa129de3c3ab8aa04b061a
Author: Kairui Song <kasong@xxxxxxxxxxx>
Date:   Tue Dec 10 00:57:16 2024 +0800

    zram: fix uninitialized ZRAM not releasing backing device
    
    [ Upstream commit 74363ec674cb172d8856de25776c8f3103f05e2f ]
    
    Setting backing device is done before ZRAM initialization.  If we set the
    backing device, then remove the ZRAM module without initializing the
    device, the backing device reference will be leaked and the device will be
    hold forever.
    
    Fix this by always reset the ZRAM fully on rmmod or reset store.
    
    Link: https://lkml.kernel.org/r/20241209165717.94215-3-ryncsn@xxxxxxxxx
    Fixes: 013bf95a83ec ("zram: add interface to specif backing device")
    Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
    Reported-by: Desheng Wu <deshengwu@xxxxxxxxxxx>
    Suggested-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
    Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
    Cc: <stable@xxxxxxxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9eed579d02f0..02efa0ca242a 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1150,12 +1150,16 @@ static void zram_meta_free(struct zram *zram, u64 disksize)
 	size_t num_pages = disksize >> PAGE_SHIFT;
 	size_t index;
 
+	if (!zram->table)
+		return;
+
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < num_pages; index++)
 		zram_free_page(zram, index);
 
 	zs_destroy_pool(zram->mem_pool);
 	vfree(zram->table);
+	zram->table = NULL;
 }
 
 static bool zram_meta_alloc(struct zram *zram, u64 disksize)
@@ -1699,11 +1703,6 @@ static void zram_reset_device(struct zram *zram)
 
 	zram->limit_pages = 0;
 
-	if (!init_done(zram)) {
-		up_write(&zram->init_lock);
-		return;
-	}
-
 	set_capacity_and_notify(zram->disk, 0);
 	part_stat_set_all(zram->disk->part0, 0);