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| author | Minchan Kim <minchan@kernel.org> | 2013-08-12 15:13:55 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-12 15:24:59 -0700 |
| commit | 2b86ab9cc29fcd435cde9378c3b9ffe8b5c76128 (patch) | |
| tree | 1248f9e8577adf4ecb1a8fe3cc5bd1adaa4e5e35 /drivers/staging/zram | |
| parent | 725acc861b55c159d9a352cf19debb023fbe1d78 (diff) | |
| download | lwn-2b86ab9cc29fcd435cde9378c3b9ffe8b5c76128.tar.gz lwn-2b86ab9cc29fcd435cde9378c3b9ffe8b5c76128.zip | |
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 <ngupta@vflare.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/zram')
| -rw-r--r-- | drivers/staging/zram/zram_drv.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 44949d21b59c..2a85b953e00e 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"); |