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SubjectRe: [PATCH 2/2] kvm: mmu: page_track: Fix RCU list API usage
On Sun, Jul 12, 2020 at 06:40:03PM +0530, madhuparnabhowmik10@gmail.com wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
> Use hlist_for_each_entry_srcu() instead of hlist_for_each_entry_rcu()
> as it also checkes if the right lock is held.
> Using hlist_for_each_entry_rcu() with a condition argument will not
> report the cases where a SRCU protected list is traversed using
> rcu_read_lock(). Hence, use hlist_for_each_entry_srcu().
>
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

I queued both for testing and review, thank you!

In particular, this one needs an ack by the maintainer.

Thanx, Paul

> ---
> arch/x86/kvm/mmu/page_track.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
> index a7bcde34d1f2..a9cd17625950 100644
> --- a/arch/x86/kvm/mmu/page_track.c
> +++ b/arch/x86/kvm/mmu/page_track.c
> @@ -229,7 +229,8 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
> return;
>
> idx = srcu_read_lock(&head->track_srcu);
> - hlist_for_each_entry_rcu(n, &head->track_notifier_list, node)
> + hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
> + srcu_read_lock_held(&head->track_srcu))
> if (n->track_write)
> n->track_write(vcpu, gpa, new, bytes, n);
> srcu_read_unlock(&head->track_srcu, idx);
> @@ -254,7 +255,8 @@ void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
> return;
>
> idx = srcu_read_lock(&head->track_srcu);
> - hlist_for_each_entry_rcu(n, &head->track_notifier_list, node)
> + hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
> + srcu_read_lock_held(&head->track_srcu))
> if (n->track_flush_slot)
> n->track_flush_slot(kvm, slot, n);
> srcu_read_unlock(&head->track_srcu, idx);
> --
> 2.17.1
>

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