Linux Kernel Vulnerability in dm cache Locking Mechanism

CVE-2026-99256

What is CVE-2026-99256?

A vulnerability in the Linux kernel's dm cache component allows improper management of locking mechanisms, specifically involving rw_semaphores. The original implementation failed to ensure that the same process that acquired the write lock on the background_work_lock was responsible for releasing it. This oversight could lead to situations where unexpected behaviors occur, particularly if the kernel is compiled with CONFIG_DEBUG_RWSEMS. Consequently, this vulnerability may be exploited in environments where dm cache is utilized, and can trigger serious warnings during operations, such as when suspending and resuming cache devices.

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