Description
In the Linux kernel, the following vulnerability has been resolved:

ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK

Commit c6e61c06d606 ("ARM: 9463/1: Allow to enable RT") enabled PREEMPT_RT
on ARM but did not select HAVE_POSIX_CPU_TIMERS_TASK_WORK. This leaves
CONFIG_POSIX_CPU_TIMERS_TASK_WORK disabled, so CPU timers expire in hard
IRQ context.

On PREEMPT_RT this makes run_posix_cpu_timers() take the sleeping
sighand->siglock:

BUG: sleeping function called from invalid context at spinlock_rt.c:48
rt_spin_lock from lock_task_sighand
lock_task_sighand from run_posix_cpu_timers
run_posix_cpu_timers from update_process_times

ARM handles TIF_NOTIFY_RESUME on all return-to-user paths, including v7-M.
ARM32 KVM host support was removed by commit 541ad0150ca4 ("arm: Remove
32bit KVM host support"), so the select need not be conditional on KVM.

Select it to defer POSIX CPU timer expiry to task context.

Reproduced with setrlimit(RLIMIT_CPU, ...) and a busy loop. The same path
is used by setitimer(ITIMER_PROF or ITIMER_VIRTUAL) and POSIX CPU timers
created with timer_create().
Published: 2026-09-17
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Thu, 17 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK Commit c6e61c06d606 ("ARM: 9463/1: Allow to enable RT") enabled PREEMPT_RT on ARM but did not select HAVE_POSIX_CPU_TIMERS_TASK_WORK. This leaves CONFIG_POSIX_CPU_TIMERS_TASK_WORK disabled, so CPU timers expire in hard IRQ context. On PREEMPT_RT this makes run_posix_cpu_timers() take the sleeping sighand->siglock: BUG: sleeping function called from invalid context at spinlock_rt.c:48 rt_spin_lock from lock_task_sighand lock_task_sighand from run_posix_cpu_timers run_posix_cpu_timers from update_process_times ARM handles TIF_NOTIFY_RESUME on all return-to-user paths, including v7-M. ARM32 KVM host support was removed by commit 541ad0150ca4 ("arm: Remove 32bit KVM host support"), so the select need not be conditional on KVM. Select it to defer POSIX CPU timer expiry to task context. Reproduced with setrlimit(RLIMIT_CPU, ...) and a busy loop. The same path is used by setitimer(ITIMER_PROF or ITIMER_VIRTUAL) and POSIX CPU timers created with timer_create().
Title ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-17T16:08:27.742Z

Reserved: 2026-09-11T19:38:34.800Z

Link: CVE-2026-90305

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-17T17:17:28.163

Modified: 2026-09-17T17:17:28.163

Link: CVE-2026-90305

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.