Bug 2536703 (CVE-2026-93040)

Summary: CVE-2026-93040 kernel: dmaengine: dw-edma: Serialize channel state checks
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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A flaw was found in the Linux kernel's `dmaengine: dw-edma` component. A race condition exists where the `pause()` and `resume()` functions can access and modify the channel state without proper synchronization, while interrupt handlers update the same state under a lock. This inconsistency can lead to a channel becoming unresponsive, effectively causing a denial of service. A local attacker could potentially exploit this to render the affected Direct Memory Access (DMA) channel unusable.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-17 19:10:09 UTC 
In the Linux kernel, the following vulnerability has been resolved:

dmaengine: dw-edma: Serialize channel state checks

pause() and resume() read and update channel state without holding vc.lock,
while the interrupt handlers update the same state under it. Take the same
lock around those state checks so that request, status, and configured stay
consistent.

For example, pause() can observe EDMA_ST_BUSY right before the interrupt
handler completes the final descriptor and moves the channel to
EDMA_ST_IDLE, and then record EDMA_REQ_PAUSE on an already idle channel. No
further interrupt will acknowledge the request, and since issue_pending()
requires EDMA_REQ_NONE, the channel is wedged for good: terminate_all()
leaves the stale request behind, so even reconfiguring the channel does not
recover it.

issue_pending() already runs under vc.lock, but it tests configured before
taking it. Move that test under the lock as well, so configured, request,
and status are evaluated as one channel-state snapshot.
Comment 1 gkamathe 2026-09-19 19:03:55 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93040.mbox