On 2023-02-21 08:04, Yu Kuai wrote:
Hi, Jens 在 2023/01/13 17:44, Yu Kuai 写道:After commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'"), bic->bfqq will be accessed in bic_set_bfqq(), however, in some context bic->bfqq will be freed first, and bic_set_bfqq() is called with the freed bic->bfqq. Fix the problem by always freeing bfqq after bic_set_bfqq(). Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'") Reported-and-tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> --- block/bfq-cgroup.c | 2 +- block/bfq-iosched.c | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index a6e8da5f5cfd..feb13ac25557 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -749,8 +749,8 @@ static void bfq_sync_bfqq_move(struct bfq_data *bfqd, * old cgroup. */ bfq_put_cooperator(sync_bfqq); - bfq_release_process_ref(bfqd, sync_bfqq); bic_set_bfqq(bic, NULL, true, act_idx); + bfq_release_process_ref(bfqd, sync_bfqq); } }It seems this change is missed in GIT PULL for-6.3. I'll send a seperate patch to fix this...
It was already applied in time for 6.2 as b600de2d7d3a16f9007fad1bdae82a3951a26af2 and also already merged to 6.1-stable. cheers Holger
