KVM: arm64: nv: Hold kvm->mmu_lock while initialising vcpu->arch.vncr_tlb

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Sashiko reports that there is a race between initialising vncr_tlb
and making use of it, as we don't hold the mmu_lock at this point.

Additionally, it identifies a memory leak, should userspace repeatedly
invokes the KVM_RUN ioctl after a failure of kvm_arch_vcpu_run_pid_change(),
as we assign vncr_tlb blindly on first run, irrespective of prior
allocations.

Slap the two bugs in one go by taking the kvm->mmu_lock on assigning
vncr_tlb, preventing the race for good, and by checking that vncr_tlb
is indeed NULL prior to allocation.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://lore.kernel.org/r/20260607180815.85FBC1F00893@smtp.kernel.org
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260608081108.2244133-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

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This commit is contained in:

Marc Zyngier 2026-06-08 09:11:08 +01:00

parent 4be6cbeb93

commit 4b54e2374d

1 changed files with 14 additions and 2 deletions

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arch/arm64/kvm/nested.c

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