CVE-2025-38009: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability has been identified in the Linux kernel's wifi mt76 driver component, designated as CVE-2025-38009. The issue was discovered when a warning started occurring after commit 9dd05df8403b regarding NAPI instance shutdown. The vulnerability affects the Linux kernel version 6.15.0-rc4 and potentially other versions, specifically impacting systems using mt76 wireless drivers (NVD).

The vulnerability stems from improper NAPI (New API) handling during driver removal in the mt76 wireless driver. The issue manifests when the tx napi is not properly disabled before deletion in mt76dmacleanup(). This was initially discovered through a warning message at net/core/dev.c:7288 in the _netifnapidellocked function. The issue was tested with mt7921e driver but affects other mt76 drivers that call mt76dmacleanup() during removal. The tx napi is enabled in their *dmainit() functions and only toggled off and on again inside their suspend/resume/reset paths (NVD).

The vulnerability can lead to system warnings and potential stability issues during driver removal operations. While the immediate impact appears to be limited to driver cleanup operations, it could potentially affect system stability during wireless driver updates or removals (NVD).

The issue has been resolved by implementing proper NAPI shutdown in the mt76dmacleanup() function. The fix involves disabling tx napi before deletion, which has been deemed safe as the tx napi is only toggled off and on during suspend/resume/reset operations (NVD).