Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2579c718 authored by Jiang Liu's avatar Jiang Liu Committed by Olav Haugan
Browse files

zram: protect sysfs handler from invalid memory access 



Use zram->init_lock to protect access to zram->meta, otherwise it
may cause invalid memory access if zram->meta has been freed by
zram_reset_device().

This issue may be triggered by:
Thread 1:
while true; do cat mem_used_total; done
Thread 2:
while true; do echo 8M > disksize; echo 1 > reset; done

Change-Id: Id6105b37f083cfd41d9885a251aeef61f72bb92f
Signed-off-by: default avatarJiang Liu <jiang.liu@huawei.com>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 5863e10b441e7ea4b492f930f1be180a97d026f3
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: default avatarOlav Haugan <ohaugan@codeaurora.org>
parent 8d5463fa

drivers/staging/zram/zram_sysfs.c

+2 −0
Original line number Diff line number Diff line
@@ -188,8 +188,10 @@ static ssize_t mem_used_total_show(struct device *dev, 
	struct zram *zram = dev_to_zram(dev);

	struct zram_meta *meta = zram->meta;



	down_read(&zram->init_lock);

	if (zram->init_done)

		val = zs_get_total_size_bytes(meta->mem_pool);

	up_read(&zram->init_lock);



	return sprintf(buf, "%llu\n", val);

}