CVE-2025-38311: iavf: get rid of the crit lock

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-10 · updated 2026-06-17
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: iavf: get rid of the crit lock Get rid of the crit lock. That frees us from the error prone logic of try_locks. Thanks to netdev_lock() by Jakub it is now easy, and in most cases we were protected by it already - replace crit lock by netdev lock when it was not the case. Lockdep reports that we should cancel the work under crit_lock [splat1], and that was the scheme we have mostly followed since [1] by Slawomir. But when that is done we still got into deadlocks [splat2]. So instead we should look at the bigger problem, namely "weird locking/scheduling" of the iavf. The first step to fix that is to remove the crit lock. I will followup with a -next series that simplifies scheduling/tasks. Cancel the work without netdev lock (weird unlock+lock scheme), to fix the [splat2] (which would be totally ugly if we would kept the crit lock). Extend protected part of iavf_watchdog_task() to include scheduling more work. Note that the removed comment in iavf_reset_task() was misplaced, it belonged to inside of the removed if condition, so it's gone now. [splat1] - w/o this patch - The deadlock during VF removal: WARNING: possible circular locking dependency detected sh/3825 is trying to acquire lock: ((work_completion)(&(&adapter->watchdog_task)->work)){+.+.}-{0:0}, at: start_flush_work+0x1a1/0x470 but task is already holding lock: (&adapter->crit_lock){+.+.}-{4:4}, at: iavf_remove+0xd1/0x690 [iavf] which lock already depends on the new lock. [splat2] - when cancelling work under crit lock, w/o this series, see [2] for the band aid attempt WARNING: possible circular locking dependency detected sh/3550 is trying to acquire lock: ((wq_completion)iavf){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90 but task is already holding lock: (&dev->lock){+.+.}-{4:4}, at: iavf_remove+0xa6/0x6e0 [iavf] which lock already depends on the new lock. [1] fc2e6b3b132a ("iavf: Rework mutexes for better synchronisation") [2] https://github.com/pkitszel/linux/commit/52dddbfc2bb60294083f5711a158a

Affected products

Linux kernel: from 6.1.42 before 6.2; from 6.4.7 before 6.5; from 6.5.1 before 6.15.3; 6.5, 6.5-rc3, 6.5-rc4, 6.5-rc5, 6.5-rc6, 6.5-rc7 — fixed in 6.15.3, 6.2, 6.5

How to fix

Upgrade to a fixed version: Linux kernel 6.15.3, 6.2, 6.5. Check the vendor advisory for mitigations.

References

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