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SubjectRe: [KVM] d3750a0923: WARNING:possible_circular_locking_dependency_detected
On Sun, Dec 5, 2021 at 10:55 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 12/5/21 14:30, kernel test robot wrote:
> >
> > Chain exists of:
> > fs_reclaim --> mmu_notifier_invalidate_range_start --> &(kvm)->mmu_lock
> >
> > Possible unsafe locking scenario:
> >
> > CPU0 CPU1
> > ---- ----
> > lock(&(kvm)->mmu_lock);
> > lock(mmu_notifier_invalidate_range_start);
> > lock(&(kvm)->mmu_lock);
> > lock(fs_reclaim);
> >
>
> David, this is yours; basically, kvm_mmu_topup_memory_cache must be
> called outside the mmu_lock.

Ah, I see. kvm_arch_mmu_enable_log_dirty_pt_masked is called with
mmu_lock already held. I'll make sure to address this in v1. In theory
this should just go away when I switch away from using split_caches to
Sean's suggestion of allocating under the mmu_lock with reclaim
disabled.

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