In the Linux kernel, the following vulnerability has been resolved:
sched/rt: Skip currently executing CPU in rto_next_cpu()
CPU0 becomes overloaded when hosting a CPU-bound RT task, a non-CPU-bound
RT task, and a CFS task stuck in kernel space. When other CPUs switch from
RT to non-RT tasks, RT load balancing (LB) is triggered; with
HAVE_RT_PUSH_IPI enabled, they send IPIs to CPU0 to drive the execution
of rto_push_irq_work_func. During push_rt_task on CPU0,
if next_task->prio < rq->donor->prio, resched_curr() sets NEED_RESCHED
and after the push operation completes, CPU0 calls rto_next_cpu().
Since only CPU0 is overloaded in this scenario, rto_next_cpu() should
ideally return -1 (no further IPI needed).
However, multiple CPUs invoking tell_cpu_to_push() during LB increments
rd->rto_loop_next. Even when rd->rto_cpu is set to -1, the mismatch between
rd->rto_loop and rd->rto_loop_next forces rto_next_cpu() to restart its
search from -1. With CPU0 remaining overloaded (satisfying rt_nr_migratory
&& rt_nr_total > 1), it gets reselected, causing CPU0 to queue irq_work to
itself and send self-IPIs repeatedly. As long as CPU0 stays overloaded and
other CPUs run pull_rt_tasks(), it falls into an infinite self-IPI loop,
which triggers a CPU hardlockup due to continuous self-interrupts.
The trigging scenario is as follows:
cpu0 cpu1 cpu2
pull_rt_task
tell_cpu_to_push
<------------irq_work_queue_on
rto_push_irq_work_func
push_rt_task
resched_curr(rq) pull_rt_task
rto_next_cpu tell_cpu_to_push
<-------------------------- atomic_inc(rto_loop_next)
rd->rto_loop != next
rto_next_cpu
irq_work_queue_on
rto_push_irq_work_func
Fix redundant self-IPI by filtering the initiating CPU in rto_next_cpu().
This solution has been verified to effectively eliminate spurious self-IPIs
and prevent CPU hardlockup scenarios.
References
Configurations
Configuration 1 (hide)
|
History
24 Jun 2026, 17:22
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-835 | |
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| First Time |
Linux linux Kernel
Linux |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| References | () https://git.kernel.org/stable/c/16ca9f3117e9a294646c897daf08a5ab546c711b - Patch | |
| References | () https://git.kernel.org/stable/c/3b3c672a66db3de3b40f8a7057864bc1f874ede3 - Patch | |
| References | () https://git.kernel.org/stable/c/52aeb1e07ec223caf212f036817976c98d2aa250 - Patch | |
| References | () https://git.kernel.org/stable/c/8ad5577b2d4acfd83f03d97a0aece2d18aac5f07 - Patch | |
| References | () https://git.kernel.org/stable/c/94894c9c477e53bcea052e075c53f89df3d2a33e - Patch | |
| References | () https://git.kernel.org/stable/c/9f25edc5a20cb52a5abbf25f0724bb4732b81801 - Patch | |
| References | () https://git.kernel.org/stable/c/a6a73403733e86748421f2eeaf028c85683ef896 - Patch | |
| References | () https://git.kernel.org/stable/c/d57d0746276a88ea43a2cc62b849fd8a95e32e41 - Patch |
27 May 2026, 14:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-27 14:17
Updated : 2026-06-24 17:22
NVD link : CVE-2026-45919
Mitre link : CVE-2026-45919
CVE.ORG link : CVE-2026-45919
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-835
Loop with Unreachable Exit Condition ('Infinite Loop')