Commit 7902a50c authored Jan 04, 2023 by Ming Lei Committed by Zheng Zengkai Jan 04, 2023

zram: avoid race between zram_remove and disksize_store

mainline inclusion
from mainline-v5.16-rc1
commit 5a4b6536
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I674BF
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5a4b653655d554b5f51a5d2252882708c56a6f7e



--------------------------------

After resetting device in zram_remove(), disksize_store still may come and
allocate resources again before deleting gendisk, fix the race by resetting
zram after del_gendisk() returns. At that time, disksize_store can't come
any more.

Reported-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: https://lore.kernel.org/r/20211025025426.2815424-4-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	drivers/block/zram/zram_drv.c

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>

parent 0896ad4c

drivers/block/zram/zram_drv.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -2023,6 +2023,13 @@ static int zram_remove(struct zram *zram)
		/* del_gendisk drains pending reset_store */
		WARN_ON_ONCE(claimed && zram->claim);

		/*
		* disksize_store() may be called in between zram_reset_device()
		* and del_gendisk(), so run the last reset to avoid leaking
		* anything allocated with disksize_store()
		*/
		zram_reset_device(zram);

		blk_cleanup_queue(zram->disk->queue);
		put_disk(zram->disk);
		kfree(zram);