In the Linux kernel, the following vulnerability has been resolved:
sched/deadline: Fix missing ENQUEUE_REPLENISH during PI de-boosting
Running stress-ng --schedpolicy 0 on an RT kernel on a big machine
might lead to the following WARNINGs (edited).
sched: DL de-boosted task PID 22725: REPLENISH flag missing
WARNING: CPU: 93 PID: 0 at kernel/sched/deadline.c:239 dequeue_task_dl+0x15c/0x1f8
... (running_bw underflow)
Call trace:
dequeue_task_dl+0x15c/0x1f8 (P)
dequeue_task+0x80/0x168
deactivate_task+0x24/0x50
push_dl_task+0x264/0x2e0
dl_task_timer+0x1b0/0x228
__hrtimer_run_queues+0x188/0x378
hrtimer_interrupt+0xfc/0x260
...
The problem is that when a SCHED_DEADLINE task (lock holder) is
changed to a lower priority class via sched_setscheduler(), it may
fail to properly inherit the parameters of potential DEADLINE donors
if it didn't already inherit them in the past (shorter deadline than
donor's at that time). This might lead to bandwidth accounting
corruption, as enqueue_task_dl() won't recognize the lock holder as
boosted.
The scenario occurs when:
1. A DEADLINE task (donor) blocks on a PI mutex held by another
DEADLINE task (holder), but the holder doesn't inherit parameters
(e.g., it already has a shorter deadline)
2. sched_setscheduler() changes the holder from DEADLINE to a lower
class while still holding the mutex
3. The holder should now inherit DEADLINE parameters from the donor
and be enqueued with ENQUEUE_REPLENISH, but this doesn't happen
Fix the issue by introducing __setscheduler_dl_pi(), which detects when
a DEADLINE (proper or boosted) task gets setscheduled to a lower
priority class. In case, the function makes the task inherit DEADLINE
parameters of the donoer (pi_se) and sets ENQUEUE_REPLENISH flag to
ensure proper bandwidth accounting during the next enqueue operation.
sched/deadline: Fix missing ENQUEUE_REPLENISH during PI de-boosting
Running stress-ng --schedpolicy 0 on an RT kernel on a big machine
might lead to the following WARNINGs (edited).
sched: DL de-boosted task PID 22725: REPLENISH flag missing
WARNING: CPU: 93 PID: 0 at kernel/sched/deadline.c:239 dequeue_task_dl+0x15c/0x1f8
... (running_bw underflow)
Call trace:
dequeue_task_dl+0x15c/0x1f8 (P)
dequeue_task+0x80/0x168
deactivate_task+0x24/0x50
push_dl_task+0x264/0x2e0
dl_task_timer+0x1b0/0x228
__hrtimer_run_queues+0x188/0x378
hrtimer_interrupt+0xfc/0x260
...
The problem is that when a SCHED_DEADLINE task (lock holder) is
changed to a lower priority class via sched_setscheduler(), it may
fail to properly inherit the parameters of potential DEADLINE donors
if it didn't already inherit them in the past (shorter deadline than
donor's at that time). This might lead to bandwidth accounting
corruption, as enqueue_task_dl() won't recognize the lock holder as
boosted.
The scenario occurs when:
1. A DEADLINE task (donor) blocks on a PI mutex held by another
DEADLINE task (holder), but the holder doesn't inherit parameters
(e.g., it already has a shorter deadline)
2. sched_setscheduler() changes the holder from DEADLINE to a lower
class while still holding the mutex
3. The holder should now inherit DEADLINE parameters from the donor
and be enqueued with ENQUEUE_REPLENISH, but this doesn't happen
Fix the issue by introducing __setscheduler_dl_pi(), which detects when
a DEADLINE (proper or boosted) task gets setscheduled to a lower
priority class. In case, the function makes the task inherit DEADLINE
parameters of the donoer (pi_se) and sets ENQUEUE_REPLENISH flag to
ensure proper bandwidth accounting during the next enqueue operation.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||
| Linux | Linux | affected |
|
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 25 Mar 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: sched/deadline: Fix missing ENQUEUE_REPLENISH during PI de-boosting Running stress-ng --schedpolicy 0 on an RT kernel on a big machine might lead to the following WARNINGs (edited). sched: DL de-boosted task PID 22725: REPLENISH flag missing WARNING: CPU: 93 PID: 0 at kernel/sched/deadline.c:239 dequeue_task_dl+0x15c/0x1f8 ... (running_bw underflow) Call trace: dequeue_task_dl+0x15c/0x1f8 (P) dequeue_task+0x80/0x168 deactivate_task+0x24/0x50 push_dl_task+0x264/0x2e0 dl_task_timer+0x1b0/0x228 __hrtimer_run_queues+0x188/0x378 hrtimer_interrupt+0xfc/0x260 ... The problem is that when a SCHED_DEADLINE task (lock holder) is changed to a lower priority class via sched_setscheduler(), it may fail to properly inherit the parameters of potential DEADLINE donors if it didn't already inherit them in the past (shorter deadline than donor's at that time). This might lead to bandwidth accounting corruption, as enqueue_task_dl() won't recognize the lock holder as boosted. The scenario occurs when: 1. A DEADLINE task (donor) blocks on a PI mutex held by another DEADLINE task (holder), but the holder doesn't inherit parameters (e.g., it already has a shorter deadline) 2. sched_setscheduler() changes the holder from DEADLINE to a lower class while still holding the mutex 3. The holder should now inherit DEADLINE parameters from the donor and be enqueued with ENQUEUE_REPLENISH, but this doesn't happen Fix the issue by introducing __setscheduler_dl_pi(), which detects when a DEADLINE (proper or boosted) task gets setscheduled to a lower priority class. In case, the function makes the task inherit DEADLINE parameters of the donoer (pi_se) and sets ENQUEUE_REPLENISH flag to ensure proper bandwidth accounting during the next enqueue operation. | |
| Title | sched/deadline: Fix missing ENQUEUE_REPLENISH during PI de-boosting | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-03-25T10:27:52.158Z
Reserved: 2026-01-13T15:37:46.003Z
Link: CVE-2026-23371
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-03-25T11:16:36.637
Modified: 2026-03-25T11:16:36.637
Link: CVE-2026-23371
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.