| From: Sergey Senozhatsky <senozhatsky@chromium.org> |
| Subject: drivers/block/zram/zram_drv.c: do not keep dangling zcomp pointer after zram reset |
| Date: Wed, 24 Aug 2022 12:51:00 +0900 |
| |
| We do all reset operations under write lock, so we don't need to save |
| ->disksize and ->comp to stack variables. Another thing is that ->comp is |
| freed during zram reset, but comp pointer is not NULL-ed, so zram keeps |
| the freed pointer value. |
| |
| Link: https://lkml.kernel.org/r/20220824035100.971816-1-senozhatsky@chromium.org |
| Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> |
| Cc: Minchan Kim <minchan@kernel.org> |
| Cc: Nitin Gupta <ngupta@vflare.org> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| --- |
| |
| drivers/block/zram/zram_drv.c | 13 ++++--------- |
| 1 file changed, 4 insertions(+), 9 deletions(-) |
| |
| --- a/drivers/block/zram/zram_drv.c~block-zram-do-not-keep-dangling-zcomp-pointer-after-zram-reset |
| +++ a/drivers/block/zram/zram_drv.c |
| @@ -1710,9 +1710,6 @@ out: |
| |
| static void zram_reset_device(struct zram *zram) |
| { |
| - struct zcomp *comp; |
| - u64 disksize; |
| - |
| down_write(&zram->init_lock); |
| |
| zram->limit_pages = 0; |
| @@ -1722,17 +1719,15 @@ static void zram_reset_device(struct zra |
| return; |
| } |
| |
| - comp = zram->comp; |
| - disksize = zram->disksize; |
| - zram->disksize = 0; |
| - |
| set_capacity_and_notify(zram->disk, 0); |
| part_stat_set_all(zram->disk->part0, 0); |
| |
| /* I/O operation under all of CPU are done so let's free */ |
| - zram_meta_free(zram, disksize); |
| + zram_meta_free(zram, zram->disksize); |
| + zram->disksize = 0; |
| memset(&zram->stats, 0, sizeof(zram->stats)); |
| - zcomp_destroy(comp); |
| + zcomp_destroy(zram->comp); |
| + zram->comp = NULL; |
| reset_bdev(zram); |
| |
| up_write(&zram->init_lock); |
| _ |
