4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> commit d5274b3cd6a814ccb2f56d81ee87cbbf51bd4cf7 upstream. Fix trivial use-after-free. This could be last reference to bfqg. Fixes: 8f9bebc33dd7 ("block, bfq: access and cache blkg data only when safe") Acked-by: Paolo Valente <paolo.valente@xxxxxxxxxx> Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- block/bfq-cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -275,9 +275,9 @@ static void bfqg_and_blkg_get(struct bfq void bfqg_and_blkg_put(struct bfq_group *bfqg) { - bfqg_put(bfqg); - blkg_put(bfqg_to_blkg(bfqg)); + + bfqg_put(bfqg); } /* @stats = 0 */