Bug 2562737 (CVE-2026-99150)

Summary: CVE-2026-99150 kernel: kernel: Denial of Service via double reference count drop in amdgpu debugfs
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: 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 AMD GPU driver. When an error occurs while copying register data to user space during a debugfs read operation, the driver improperly releases a runtime Power Management (PM) reference twice. A local user could exploit this flaw by providing an invalid memory buffer, triggering a reference count underflow that may cause system instability or a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-10-28 11:00:07 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: don't drop the runtime PM reference twice in amdgpu_gpr

amdgpu_debugfs_gpr_read() drops its runtime PM reference right after
reading the wave registers. When copying them to userspace fails, it
jumps to the err label, which drops the reference a second time. A read
into a bad buffer on Navi31 either steals a reference somebody else
holds (power/runtime_usage goes from 1 to 0) or underflows the count:

  amdgpu 0000:03:00.0: Runtime PM usage count underflow!

The registers are already in the kernel buffer at that point, so finish
the hardware access first and copy the buffer with a single
copy_to_user() instead of the put_user() loop with its own error path.

(cherry picked from commit 31035bbd74f7c3e10c163db875b8e67f8b50ee6a)