CVE-2025-40142ALSA: pcm: Disable bottom softirqs as part of spin_lock_irq() on PREEMPT_RT
- —Not scoredno CVSS score yet
- 0.21%Exploitation in 30 daysEPSS · top 89% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Disable bottom softirqs as part of spin_lock_irq() on PREEMPT_RT snd_pcm_group_lock_irq() acquires a spinlock_t and disables interrupts via spin_lock_irq(). This also implicitly disables the handling of softirqs such as TIMER_SOFTIRQ. On PREEMPT_RT softirqs are preemptible and spin_lock_irq() does not disable them. That means a timer can be invoked during spin_lock_irq() on the same CPU. Due to synchronisations reasons local_bh_disable() has a per-CPU lock named softirq_ctrl.lock which synchronizes individual softirq against each other. syz-bot managed to trigger a lockdep report where softirq_ctrl.lock is acquired in hrtimer_cancel() in addition to hrtimer_run_softirq(). This is a possible deadlock. The softirq_ctrl.lock can not be made part of spin_lock_irq() as this would lead to too much synchronisation against individual threads on the system. To avoid the possible deadlock, softirqs must be manually disabled before the lock is acquired. Disable softirqs before the lock is acquired on PREEMPT_RT.
Timeline
ID reserved
By Linux
- 7 months later
· 7 months later
Published
- 6 months later
· 6 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Deferred.
- EPSS (exploitation in 30 days)
- 0.21% · top 89% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected d2d6422f8bd17c6bb205133e290625a564194496 – < 63ee96c7f47df239ee0a6e8108b6bfd8c98334ae
- affected d2d6422f8bd17c6bb205133e290625a564194496 – < 3969b6193cb7a45aa5fb4ec68f215e9e7f93d39a
- affected d2d6422f8bd17c6bb205133e290625a564194496 – < 9fc4a3da9a0259a0500848b5d8657918efde176b
- affected 6.12
- unaffected < 6.12
- unaffected 6.12.53 – ≤ 6.12.*
- unaffected 6.17.3 – ≤ 6.17.*
- unaffected 6.18 – ≤ *
References
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-124941 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-40142)Record last updated .