CVE-2026-43115: srcu: Use irq_work to start GP in tiny SRCU

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-06 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: srcu: Use irq_work to start GP in tiny SRCU Tiny SRCU's srcu_gp_start_if_needed() directly calls schedule_work(), which acquires the workqueue pool->lock. This causes a lockdep splat when call_srcu() is called with a scheduler lock held, due to: call_srcu() [holding pi_lock] srcu_gp_start_if_needed() schedule_work() -> pool->lock workqueue_init() / create_worker() [holding pool->lock] wake_up_process() -> try_to_wake_up() -> pi_lock Also add irq_work_sync() to cleanup_srcu_struct() to prevent a use-after-free if a queued irq_work fires after cleanup begins. Tested with rcutorture SRCU-T and no lockdep warnings. [ Thanks to Boqun for similar fix in patch "rcu: Use an intermediate irq_work to start process_srcu()" ]

Affected products

Linux kernel: from 4.12 before 6.19.14; 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5 — fixed in 6.19.14
Linux: 4.12 — fixed in 7.0

How to fix

Upgrade to a fixed version: Linux kernel 6.19.14; Linux 7.0. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-43115 or the next vulnerability affects your stack