CVE-2022-50100 sched/core: Do not requeue task on CPU excluded from cpus_mask
A race condition in the Linux kernel scheduler can trigger a warning and potential instability during boot on large machines.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-50100?
CVE-2022-50100 is a medium-severity vulnerability in Linux kernel, published on 18 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
sched/core: Do not requeue task on CPU excluded from cpus_mask
The following warning was triggered on a large machine early in boot on a distribution kernel but the same problem should also affect mainline.
WARNING: CPU: 439 PID: 10 at ../kernel/workqueue.c:2231 process_one_work+0x4d/0x440 Call Trace: <TASK> rescuer_thread+0x1f6/0x360 kthread+0x156/0x180 ret_from_fork+0x22/0x30 </TASK>
Commit c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu") optimises ttwu by queueing a task that is descheduling on the wakelist, but does not check if the task descheduling is still allowed to run on that CPU.
In this warning, the problematic task is a workqueue rescue thread which checks if the rescue is for a per-cpu workqueue and running on the wrong CPU. While this is early in boot and it should be possible to create workers, the rescue thread may still used if the MAYDAY_INITIAL_TIMEOUT is reached or MAYDAY_INTERVAL and on a sufficiently large machine, the rescue thread is being used frequently.
Tracing confirmed that the task should have migrated properly using the stopper thread to handle the migration. However, a parallel wakeup from udev running on another CPU that does not share CPU cache observes p->on_cpu and uses task_cpu(p), queues the task on the old CPU and triggers the warning.
Check that the wakee task that is descheduling is still allowed to run on its current CPU and if not, wait for the descheduling to complete and select an allowed CPU.
Which versions are affected by CVE-2022-50100?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-50100?
Apply the vendor's patch.
Is CVE-2022-50100 being exploited?
There is no known exploitation of CVE-2022-50100 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-50100, GHSA-2xp7-4xpw-h487, ROOT-OS-DEBIAN-11-CVE-2022-50100, UBUNTU-CVE-2022-50100.