CVE-2026-98433: KVM: PPC: Book3S HV: fix secure device page leak on uv_page_in() failure
In the Linux kernel, the following vulnerability has been resolved:
KVM: PPC: Book3S HV: fix secure device page leak on uvpagein() failure
In kvmppcsvmpagein(), if uvpagein() fails after kvmppcuvmemgetpage() has succeeded, the secure device page is never released. kvmppcuvmemgetpage() sets a bit in kvmppcuvmembitmap, allocates a kvmppcuvmempagepvt struct, marks the GFN as KVMPPCGFNUVMEMPFN, and calls zonedevicepageinit() which sets refcount=1 and locks the page. The subsequent goto outfinalize skips the mig.dst assignment, so migratevmafinalize() is a no-op for the page, and none of those resources are ever reclaimed.
Each occurrence permanently consumes one entry from the firmware-bounded secure memory pool (kvmppcuvmembitmap), leaks pvt, and leaves the GFN marked as secure — making it unusable for the lifetime of the VM.
The twin kvmppcsvmpageout() already handles the analogous uvpageout() failure correctly with unlockpage(dpage); freepage(dpage). Apply the same pattern here: unlockpage() followed by putpage(), which chains through freezonedevicefolio() into kvmppcuvmemfoliofree() to clear the bitmap bit, free pvt, and reset the GFN state.
Reachable whenever uvpagein() returns an error (e.g. UV pool exhaustion) on any POWER9/10 + Ultravisor/PEF system.
Affected Software
Remediation
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In kvmppc_svm_page_in(), when uv_page_in() fails after kvmppc_uvmem_get_page() succeeds, release the secure device page with unlock_page() followed by put_page(); this must clear the kvmppc_uvmem_bitmap bit, free the kvmppc_uvmem_page_pvt structure, and reset the GFN state.
Event History
Frequently Asked Questions
Which systems are exposed to this leak?
The issue is in Linux kernel KVM for PowerPC Book3S HV secure-VM handling. It affects the kvmppc_svm_page_in() path when uv_page_in() fails after a secure device page has been obtained.
What condition triggers the resource leak?
A failure from uv_page_in() after kvmppc_uvmem_get_page() succeeds triggers the leak. The affected error path skips migration finalization and does not release the locked secure device page.
What is the operational impact if this occurs repeatedly?
Each occurrence permanently consumes an entry in the firmware-bounded secure-memory pool, leaks associated private state, and leaves the guest frame number marked as secure. The affected GFN remains unusable for the lifetime of the VM.
What does the fix do?
The fix releases the page on the uv_page_in() failure path by unlocking it and calling put_page(). This allows the zone-device-page cleanup path to clear the bitmap entry, free private state, and reset the GFN state.