CVE-2026-46042

Summary

In the Linux kernel, the following vulnerability has been resolved:

mm/mempolicy: fix memory leaks in weighted_interleave_auto_store()

weighted_interleave_auto_store() fetches old_wi_state inside the if (!input) block only. This causes two memory leaks:

1. When a user writes "false" and the current mode is already manual, the function returns early without freeing the freshly allocated new_wi_state.

2. When a user writes "true", old_wi_state stays NULL because the fetch is skipped entirely. The old state is then overwritten by rcu_assign_pointer() but never freed, since the cleanup path is gated on old_wi_state being non-NULL. A user can trigger this repeatedly by writing "1" in a loop.

Fix both leaks by moving the old_wi_state fetch before the input check, making it unconditional. This also allows a unified early return for both "true" and "false" when the requested mode matches the current mode.

Reviewed by: Donet Tom <donettom@linux.ibm.com>

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/c42a7efb9060d89b72708ffaf255d0002c2164a7
• https://git.kernel.org/stable/c/39caa9ca863f96b3d00447c5aa200cabda489856
• https://git.kernel.org/stable/c/6fae274ce0e3109cbbc4c18b354eaace1f0af7d7

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