From 5fc58bd448ae1b2bafd83fcb5e2c0d65fcee2c37 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Mon, 12 Aug 2013 15:13:55 +0900 Subject: zram: fix invalid memory access [1] tried to fix invalid memory access on zram->disk but it didn't fix properly because get_disk failed during module exit path. Actually, we don't need to reset zram->disk's capacity to zero in module exit path so that this patch introduces new argument "reset_capacity" on zram_reset_divice and it only reset it when reset_store is called. [1] 6030ea9b, zram: avoid invalid memory access in zram_exit() Cc: Nitin Gupta Cc: Jiang Liu Cc: stable@vger.kernel.org Signed-off-by: Minchan Kim Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 2b86ab9cc29fcd435cde9378c3b9ffe8b5c76128) Signed-off-by: Alex Shi --- drivers/staging/zram/zram_drv.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'drivers/staging/zram/zram_drv.c') diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 35d536a11395..255d512763f2 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -523,7 +523,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, return ret; } -static void zram_reset_device(struct zram *zram) +static void zram_reset_device(struct zram *zram, bool reset_capacity) { size_t index; struct zram_meta *meta; @@ -552,7 +552,8 @@ static void zram_reset_device(struct zram *zram) memset(&zram->stats, 0, sizeof(zram->stats)); zram->disksize = 0; - set_capacity(zram->disk, 0); + if (reset_capacity) + set_capacity(zram->disk, 0); up_write(&zram->init_lock); } @@ -636,7 +637,7 @@ static ssize_t reset_store(struct device *dev, if (bdev) fsync_bdev(bdev); - zram_reset_device(zram); + zram_reset_device(zram, true); return len; } @@ -903,10 +904,12 @@ static void __exit zram_exit(void) for (i = 0; i < num_devices; i++) { zram = &zram_devices[i]; - get_disk(zram->disk); destroy_device(zram); - zram_reset_device(zram); - put_disk(zram->disk); + /* + * Shouldn't access zram->disk after destroy_device + * because destroy_device already released zram->disk. + */ + zram_reset_device(zram, false); } unregister_blkdev(zram_major, "zram"); -- cgit v1.2.3