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drivers/block/zram/zram_drv.c: do not keep dangling zcomp pointer after zram reset

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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>
This commit is contained in:
Sergey Senozhatsky 2022-08-24 12:51:00 +09:00 committed by Andrew Morton
parent 67e139b02d
commit 6d2453c3db
1 changed files with 4 additions and 9 deletions
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13
drivers/block/zram/zram_drv.c
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@ -1710,9 +1710,6 @@ out:
static void zram_reset_device(struct zram *zram) static void zram_reset_device(struct zram *zram)
{ {
struct zcomp *comp;
u64 disksize;
down_write(&zram->init_lock); down_write(&zram->init_lock);
zram->limit_pages = 0; zram->limit_pages = 0;
@ -1722,17 +1719,15 @@ static void zram_reset_device(struct zram *zram)
return; return;
} }
comp = zram->comp;
disksize = zram->disksize;
zram->disksize = 0;
set_capacity_and_notify(zram->disk, 0); set_capacity_and_notify(zram->disk, 0);
part_stat_set_all(zram->disk->part0, 0); part_stat_set_all(zram->disk->part0, 0);
/* I/O operation under all of CPU are done so let's free */ /* 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)); memset(&zram->stats, 0, sizeof(zram->stats));
zcomp_destroy(comp); zcomp_destroy(zram->comp);
zram->comp = NULL;
reset_bdev(zram); reset_bdev(zram);
up_write(&zram->init_lock); up_write(&zram->init_lock);