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@xxxxxxxxxxx>
Subject: zram: fix uninitialized ZRAM not releasing backing device
Date: Tue, 10 Dec 2024 00:57:16 +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 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>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-fix-uninitialized-zram-not-releasing-backing-device
+++ a/drivers/block/zram/zram_drv.c
@@ -1444,12 +1444,16 @@ static void zram_meta_free(struct zram *
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)
@@ -2334,11 +2338,6 @@ static void zram_reset_device(struct zra
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);
_
Patches currently in -mm which might be from kasong@xxxxxxxxxxx are
zram-refuse-to-use-zero-sized-block-device-as-backing-device.patch
zram-fix-uninitialized-zram-not-releasing-backing-device.patch
