CVE-2025-40142

A flaw was found in the Linux kernel’s Advanced Linux Sound Architecture PCM subsystem when built with the PREEMPT_RT (real-time) configuration. In snd_pcm_group_lock_irq(), the code uses spin_lock_irq() to acquire a spinlock and disable interrupts. However, on PREEMPT_RT systems, softirqs (e.g., TIMER_SOFTIRQ) remain preemptible, so a timer softirq may be raised on the same CPU during the lock. This interacts badly with softirq_ctrl.lock (a per-CPU lock used by local_bh_disable()), potentially causing a deadlock.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.