Medium [CVE-2026-63863] Fix unbalanced unlock in drm_gpusvm_scan_mm
This medium-severity Red Hat Linux advisory covers CVE-2026-63863 affecting Red Hat Enterprise Linux 9, Red Hat package: kernel-rt.
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Summary
In the Linux kernel, the following vulnerability has been resolved: drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm() There is a unbalanced lock/unlock to gpusvm notifier lock: [ 931.045868] ===================================== [ 931.046509] WARNING: bad unlock balance detected! [ 931.047149] 6.19.0-rc6+xe-**************** #9 Tainted: G U [ 931.048150] ------------------------------------- [ 931.048790] kworker/u5:0/51 is trying to release lock (&gpusvm->notifier_lock) at: [ 931.049801] [] drm_gpusvm_scan_mm+0x188/0x460 [drm_gpusvm_helper] [ 931.050802] but there are no more locks to release! [ 931.051463] The drm_gpusvm_notifier_unlock() sits under err_free label and the first jump to err_free is just before calling the drm_gpusvm_notifier_lock() causing unbalanced unlock.
A flaw was found in the Linux kernel's Direct Rendering Manager (DRM) Graphics Processing Unit Shared Virtual Memory (gpusvm) component. This vulnerability is caused by an unbalanced lock and unlock operation, which can lead to system instability.
An attacker could potentially exploit this to trigger a denial of service, making the system unresponsive. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-832. Affected Red Hat products: Red Hat Enterprise Linux 9.
Red Hat does not currently list a fixing RHSA for this CVE.
- < 931.045868
- < 931.046509
- < 931.047149
- < 6.19.0-rc6
- < 931.048150
- < 931.048790
- < 931.049801
- < 931.050802
- < 931.051463
Official advisory · high-confidence parse· fetched 7 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 7 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · high-confidence parse· fetched 7 days ago·verify at source
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