Recursive Semaphore Deadlock in OCFS2 of Linux Kernel

CVE-2025-39885

What is CVE-2025-39885?

The vulnerability in the Linux kernel's OCFS2 filesystem involves a recursive semaphore deadlock triggered during the execution of the FS_IOC_FIEMAP command on a specially crafted mmap file. When an OCFS2 operation attempts to acquire a write lock while holding a read lock on the same semaphore, it leads to a system hang, impacting file system performance and stability. The issue has been identified and resolved by releasing the read semaphore before engaging in further processing, which mitigates the unnecessary locking mechanism. Addressing this vulnerability is crucial for maintaining overall system integrity and preventing potential disruptions.

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