Overview
About vulnerability
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.
Details
- Affected product:
- Debian 10 ELS , Debian 11 ELS
- Affected packages:
- linux @ 5.10.259 (+1 more)