This is a note to let you know that I've just added the patch titled block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: block-bfq-fix-uaf-for-bfqq-in-bfq_exit_icq_bfqq.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 8d578c6a8eb0a4e63490fb7f8d2aa9bc5cee23d2 Author: Yu Kuai <yukuai3@xxxxxxxxxx> Date: Mon Mar 13 15:27:54 2023 -0700 block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq [ Upstream commit 246cf66e300b76099b5dbd3fdd39e9a5dbc53f02 ] Commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'") will access 'bic->bfqq' in bic_set_bfqq(), however, bfq_exit_icq_bfqq() can free bfqq first, and then call bic_set_bfqq(), which will cause uaf. Fix the problem by moving bfq_exit_bfqq() behind bic_set_bfqq(). Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'") Reported-by: Yi Zhang <yi.zhang@xxxxxxxxxx> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> Link: https://lore.kernel.org/r/20221226030605.1437081-1-yukuai1@xxxxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> Signed-off-by: Khazhismel Kumykov <khazhy@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index afaededb3c49c..0a53b653a7e2e 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -4983,8 +4983,8 @@ static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync) unsigned long flags; spin_lock_irqsave(&bfqd->lock, flags); - bfq_exit_bfqq(bfqd, bfqq); bic_set_bfqq(bic, NULL, is_sync); + bfq_exit_bfqq(bfqd, bfqq); spin_unlock_irqrestore(&bfqd->lock, flags); } }