Hi,
在 2023/02/21 18:19, Holger Hoffstätte 写道:
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.
Yes, 6.2 and 6.1 doesn't have such problem because bfq_sync_bfqq_move()
doesn't exist. The problem only exist in master branch currently.
Thanks,
Kuai
cheers
Holger
.
