CVE-2022-50100

sched/core: Do not requeue task on CPU excluded from cpus_mask

Published Jun 18, 2025 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2022-55366 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.
History
Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
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.
Title sched/core: Do not requeue task on CPU excluded from cpus_mask
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
May 11, 2026, 7:12 PM
Reserved
Jun 18, 2025, 10:57 AM
Status
Analyzed
Published
Jun 18, 2025, 11:15 AM
Modified
Jun 17, 2026, 5:22 AM
Severity
Moderate
Public date
Jun 18, 2025, 12:00 AM