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From: Ben Gardon <bgardon@google.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Peter Shier <pshier@google.com>,
	Jim Mattson <jmattson@google.com>,
	Ben Gardon <bgardon@google.com>,
	kernel test robot <lkp@intel.com>
Subject: [PATCH v3 2/4] KVM: x86/mmu: Fix RCU usage when atomically zapping SPTEs
Date: Mon, 15 Mar 2021 16:38:01 -0700	[thread overview]
Message-ID: <20210315233803.2706477-3-bgardon@google.com> (raw)
In-Reply-To: <20210315233803.2706477-1-bgardon@google.com>

Fix a missing rcu_dereference in tdp_mmu_zap_spte_atomic.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
---
 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 db2936cca4bf..946da74e069c 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -543,7 +543,7 @@ 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


  parent reply	other threads:[~2021-03-15 23:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-15 23:37 [PATCH v3 0/4] Fix RCU warnings in TDP MMU Ben Gardon
2021-03-15 23:38 ` [PATCH v3 1/4] KVM: x86/mmu: Fix RCU usage in handle_removed_tdp_mmu_page Ben Gardon
2021-03-15 23:38 ` Ben Gardon [this message]
2021-03-16 17:54   ` [PATCH v3 2/4] KVM: x86/mmu: Fix RCU usage when atomically zapping SPTEs Sean Christopherson
2021-03-15 23:38 ` [PATCH v3 3/4] KVM: x86/mmu: Factor out tdp_iter_return_to_root Ben Gardon
2021-03-16 17:55   ` Sean Christopherson
2021-03-15 23:38 ` [PATCH v3 4/4] KVM: x86/mmu: Store the address space ID in the TDP iterator Ben Gardon
2021-03-16 18:16 ` [PATCH v3 0/4] Fix RCU warnings in TDP MMU Paolo Bonzini

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