From: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx> [ Upstream commit 72ce11ddfa4e9e1879103581a60b7e34547eaa0a ] In null_init, null_add_dev(dev) is called. In null_add_dev, it calls null_free_zoned_dev(dev) to free dev->zones via kvfree(dev->zones) in out_cleanup_zone branch and returns err. Then null_init accept the err code and then calls null_free_dev(dev). But in null_free_dev(dev), dev->zones is freed again by null_free_zoned_dev(). My patch set dev->zones to NULL in null_free_zoned_dev() after kvfree(dev->zones) is called, to avoid the double free. Fixes: 2984c8684f962 ("nullb: factor disk parameters") Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210426143229.7374-1-lyl2019@xxxxxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/block/null_blk_zoned.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c index 079ed33fd806..ba018f1da512 100644 --- a/drivers/block/null_blk_zoned.c +++ b/drivers/block/null_blk_zoned.c @@ -56,6 +56,7 @@ int null_zone_init(struct nullb_device *dev) void null_zone_exit(struct nullb_device *dev) { kvfree(dev->zones); + dev->zones = NULL; } static void null_zone_fill_bio(struct nullb_device *dev, struct bio *bio, -- 2.30.2