CVE-2026-89764rust: devres: fix race between concurrent revokers

Official description

In the Linux kernel, the following vulnerability has been resolved: rust: devres: fix race between concurrent revokers There is a potential race condition when two paths try to revoke a Devres concurrently. The driver core's devres_release_all() calls Revocable::revoke() via the release callback, while Devres::drop() calls revoke_nosync() on another CPU. The revoker that does not claim the is_available swap returns immediately, but the revoker that did may still be executing drop_in_place() on the inner data. This can cause a use-after-free when the other revoker's caller proceeds to drop adjacent resources that drop_in_place() still references (e.g., Devres<DmaMappedSgt> racing with SGTable freeing the backing sg_table and pages). Fix this by adding a Completion. The release callback signals the Completion after revoke() finishes, and Devres::drop() waits for it when it loses the is_available swap. This ensures the wrapped object is fully torn down before Devres::drop() returns.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e7930d857cc7930fc39b487ea9f3a453eca3713e
• https://git.kernel.org/stable/c/c7e3d57c705ab1053a6a1bbef96795e792da1540
• https://git.kernel.org/stable/c/acc516dfa1972d31836b50abc0115216cd0fccc5