[PATCH 3/4] KVM: x86/mmu: Fix RCU usage when atomically zapping SPTEs

From: Ben Gardon
Date: Thu Mar 11 2021 - 18:18:51 EST


Fix a missing rcu_dereference in tdp_mmu_zap_spte_atomic.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx>
---
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 6c8824bcc2f2..a8fdccf4fd06 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -532,7 +532,7 @@ static inline bool tdp_mmu_zap_spte_atomic(struct kvm *kvm,
* here since the SPTE is going from non-present
* to non-present.
*/
- WRITE_ONCE(*iter->sptep, 0);
+ WRITE_ONCE(*rcu_dereference(iter->sptep), 0);

return true;
}
--
2.31.0.rc2.261.g7f71774620-goog