parisc: led: Fix potential null-ptr-deref in start_task()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: parisc: led: Fix potential null-ptr-deref in start_task() start_task() calls create_singlethread_workqueue() and not checked the ret value, which may return NULL. And a null-ptr-deref may happen: start_task() create_singlethread_workqueue() # failed, led_wq is NULL queue_delayed_work() queue_delayed_work_on() __queue_delayed_work() # warning here, but continue __queue_work() # access wq->flags, null-ptr-deref Check the ret value and return -ENOMEM if it is NULL.

References

• https://git.kernel.org/stable/c/c6db0c32f39684c89c97bc1ba1c9c4249ca09e48
• https://git.kernel.org/stable/c/fc6d0f65f22040c6cc8a5ce032bf90252629de50
• https://git.kernel.org/stable/c/fc307b2905a3dd75c50a53b4d87ac9c912fb7c4e
• https://git.kernel.org/stable/c/5e4500454d75dd249be4695d83afa3ba0724c37e
• https://git.kernel.org/stable/c/3505c187b86136250b39e62c72a3a70435277af6
• https://git.kernel.org/stable/c/ac838c663ba1fd6bff35a817fd89a47ab55e88e0
• https://git.kernel.org/stable/c/77f8b628affaec692d83ad8bfa3520db8a0cc493
• https://git.kernel.org/stable/c/67c98fec87ed76b1feb2ae810051afd88dfa9df6
• https://git.kernel.org/stable/c/41f563ab3c33698bdfc3403c7c2e6c94e73681e4