Linux Kernel Vulnerability in NFS File Handling

CVE-2024-56743

Summary

A vulnerability exists in the Linux kernel within the NFS file handling mechanism. Specifically, the issue arises when the nfs_common layer improperly holds Read-Copy Update (RCU) during calls to 'nfsd_file_put_local'. This mismanagement can result in a situation where a voluntary context switch occurs while still within the RCU read-side critical section, leading to unexpected behaviors. The vulnerability has been identified to fix recurring failures during tests, specifically xfstests generic/013, where it triggers errors indicating context switching within RCU. The flaw has been addressed by altering the RCU handling process, ensuring smoother operational integrity and preventing potential disruptions in file operations.

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