CVE-2026-90305

unknown
EUVD alias: EUVD-2026-81966
Assigned by CNA: linux
Published 2026-09-17 · Modified 2026-09-17
CVSS v3
CVSS v4 NEW
not yet in upstream
VIR risk

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().

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

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References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.