On (24/12/05 02:02), Kairui Song wrote:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> 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.
>
> Fixes: 013bf95a83ec ("zram: add interface to specif backing device")
> Reported-by: Desheng Wu <deshengwu@xxxxxxxxxxx>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/block/zram/zram_drv.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index dd48df5b97c8..dfe9a994e437 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -2335,6 +2335,9 @@ static void zram_reset_device(struct zram *zram)
> 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;
> }
> --
So here I think we better remove that if entirely and always reset
the device. Something like this (untested):
---
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 0ca6d55c9917..8773b12afc9d 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1438,12 +1438,16 @@ 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)
@@ -2327,12 +2331,6 @@ static void zram_reset_device(struct zram *zram)
down_write(&zram->init_lock);
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);
