Vulnerability in Linux

[ Description ]Official description

In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix NULL current_pwq deref in chained work check current_wq_worker() only tells us that %current is a kworker. It does not guarantee that the worker is currently executing a work item, as worker->current_pwq is populated only while process_one_work() is running the work function. is_chained_work() can be reached while queueing on a draining or destroying workqueue. If a kworker outside work-item execution reaches that path, current_wq_worker() returns a worker but worker->current_pwq is NULL, and the chained-work test can fault before it emits the intended warning. Guard the chained-work test with worker->current_pwq. A kworker without current_pwq is not executing work on the target workqueue, so the helper should return false and let the draining/destroying warning fire.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• git.kernel.org/stable/c/1a2668682e998039a027796b236319b380078a6a
• git.kernel.org/stable/c/3dc61af2998cfc7312d6e59bbdcd5eed074483f2
• git.kernel.org/stable/c/729d576df89c7e4341e58c452f8890620a610ac2
• git.kernel.org/stable/c/980db94e3eeefdd8a1c46f86412c33a7f7806f51
• git.kernel.org/stable/c/b12a25fb2b9d5dac80e419d695450cc17a51fdfd