Re: [PATCH v3] mac802154: Fix potential RCU dereference issue in mac802154_scan_worker

From: Przemek Kitszel
Date: Tue Sep 24 2024 - 05:12:49 EST


On 9/24/24 08:58, Jiawei Ye wrote:
In the `mac802154_scan_worker` function, the `scan_req->type` field was
accessed after the RCU read-side critical section was unlocked. According
to RCU usage rules, this is illegal and can lead to unpredictable
behavior, such as accessing memory that has been updated or causing
use-after-free issues.

This possible bug was identified using a static analysis tool developed
by myself, specifically designed to detect RCU-related issues.

To address this, the `scan_req->type` value is now stored in a local
variable `scan_req_type` while still within the RCU read-side critical
section. The `scan_req_type` is then used after the RCU lock is released,
ensuring that the type value is safely accessed without violating RCU
rules.

Fixes: e2c3e6f53a7a ("mac802154: Handle active scanning")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiawei Ye <jiawei.ye@xxxxxxxxxxx>
Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@xxxxxxxxx>