Locking Assertion Issue in fbnic Driver Affecting Linux Kernel

CVE-2025-39831

What is CVE-2025-39831?

The fbnic driver within the Linux kernel has been found to exhibit a locking assertion failure during power management resume operations. This vulnerability arises when phylink_resume is invoked within the fbnic_up path without holding the required RTNL lock. As a result, this can lead to system instability. Proper enforcement of locking mechanisms should occur when bringing the phylink interface online in conjunction with the network interface, ensuring a more stable operation. A fix has been implemented to shift the phylink resume process to the ndo_open path to prevent future occurrences of this issue.

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