[PATCH V3 1/4] zram: fix race between zram_reset_device() and disksize_store()
From: Ming Lei <hidden>
Date: 2021-10-25 02:54:53
Also in:
lkml
Subsystem:
block layer, the rest, zram compressed ram block device drvier · Maintainers:
Jens Axboe, Linus Torvalds, Minchan Kim, Sergey Senozhatsky
When the ->init_lock is released in zram_reset_device(), disksize_store() can come in and try to allocate meta, but zram_reset_device() is freeing free meta, so cause races. Link: https://lore.kernel.org/linux-block/20210927163805.808907-1-mcgrof@kernel.org/T/#mc617f865a3fa2778e40f317ddf48f6447c20c073 (local) Reported-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Ming Lei <redacted> --- drivers/block/zram/zram_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a68297fb51a2..25d781dc5fef 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c@@ -1704,12 +1704,13 @@ static void zram_reset_device(struct zram *zram) set_capacity_and_notify(zram->disk, 0); part_stat_set_all(zram->disk->part0, 0); - up_write(&zram->init_lock); /* I/O operation under all of CPU are done so let's free */ zram_meta_free(zram, disksize); memset(&zram->stats, 0, sizeof(zram->stats)); zcomp_destroy(comp); reset_bdev(zram); + + up_write(&zram->init_lock); } static ssize_t disksize_store(struct device *dev,
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2.31.1