Bug 2532452 (CVE-2026-89764)

Summary: CVE-2026-89764 kernel: rust: devres: fix race between concurrent revokers
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's `rust: devres` component. A race condition exists when two processes attempt to revoke a `Devres` resource concurrently. This can lead to a use-after-free vulnerability, where one process might free resources that another process is still actively using. Such an issue could result in system instability or unexpected behavior.
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Description OSIDB Bzimport 2026-09-11 23:20:05 UTC 
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.
Comment 1 Keith Grant 2026-09-21 17:48:54 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89764.mbox