Circular Locking Dependency in Linux Kernel NFC Component

CVE-2026-31509

What is CVE-2026-31509?

A circular locking dependency has been identified in the NFC component of the Linux kernel, specifically during the execution of the nci_close_device function. This occurs when both rx_wq and tx_wq are flushed while holding the req_lock, which can lead to the function nci_rx_work acquiring req_lock while it is still held. The issue has been observed during nci selftests with a debug kernel, affecting about 4% of test runs. To mitigate this, the flush of rx_wq should occur after the req_lock has been released to prevent this deadlock situation.

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