Harry Yoo

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** An issue exists in the memory control group (memcg) where the `get random u32 below()` function is called during memcg charge draining, which can occur in the Non-Maskable Interrupt (NMI) context. The `get random u32 below()` function is neither reentrant nor NMI-safe because it acquires a per-cpu local lock on the `batched entropy u32` state. If an NMI occurs while the CPU is updating the ChaCha batch state and subsequently calls the random subsystem, it can lead to state corruption. While the `memcg stock` local trylock prevents re-entry on the per-cpu stock, it does not protect the locks of unrelated subsystems. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.