Linux Kernel NFS Vulnerability Involving LOCALIO Functionality

CVE-2026-46256

What is CVE-2026-46256?

A vulnerability in the Linux kernel affects the LOCALIO feature used with NFS loopback mounts, allowing the potential for recursion deadlock. This primarily arises when NFS operations are optimized to skip network traffic due to the client and server being on the same system. However, this implementation inadvertently makes it vulnerable to deadlocks during direct reclaim processes. To mitigate this risk, the kernel has implemented a fix ensuring that all page cache allocations from LOCALIO are executed within the GFP_NOFS context, effectively preventing the path that leads to stack overflows.

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