+ zram-fix-uninitialized-zram-not-releasing-backing-device.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: zram: fix uninitialized ZRAM not releasing backing device
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     zram-fix-uninitialized-zram-not-releasing-backing-device.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-fix-uninitialized-zram-not-releasing-backing-device.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Kairui Song <kasong@tencent.com>
Subject: zram: fix uninitialized ZRAM not releasing backing device
Date: Thu, 5 Dec 2024 02:02:24 +0800

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 check and release the backing device when resetting or
removing ZRAM.

Link: https://lkml.kernel.org/r/20241204180224.31069-3-ryncsn@gmail.com
Fixes: 013bf95a83ec ("zram: add interface to specif backing device")
Signed-off-by: Kairui Song <kasong@tencent.com>
Reported-by: Desheng Wu <deshengwu@tencent.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/block/zram/zram_drv.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/block/zram/zram_drv.c~zram-fix-uninitialized-zram-not-releasing-backing-device
+++ a/drivers/block/zram/zram_drv.c
@@ -2335,6 +2335,9 @@ static void zram_reset_device(struct zra
 	zram->limit_pages = 0;
 
 	if (!init_done(zram)) {
+		/* Backing device could be set before ZRAM initialization. */
+		reset_bdev(zram);
+
 		up_write(&zram->init_lock);
 		return;
 	}
_

Patches currently in -mm which might be from kasong@tencent.com are

zram-refuse-to-use-zero-sized-block-device-as-backing-device.patch
zram-fix-uninitialized-zram-not-releasing-backing-device.patch