linux-kernel - [PATCH 5/6] KVM: Don't BUG() the kernel if xa

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Message-ID: <20241009150455.1057573-6-seanjc@google.com>
Date: Wed,  9 Oct 2024 08:04:54 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Will Deacon <will@...nel.org>, Michal Luczaj <mhal@...x.co>, Sean Christopherson <seanjc@...gle.com>, 
	Alexander Potapenko <glider@...gle.com>, Marc Zyngier <maz@...nel.org>, 
	Oliver Upton <oliver.upton@...ux.dev>
Subject: [PATCH 5/6] KVM: Don't BUG() the kernel if xa_insert() fails with -EBUSY

WARN once instead of triggering a BUG if xa_insert() fails because it
encountered an existing entry.  While KVM guarantees there should be no
existing entry, there's no reason to BUG the kernel, as KVM needs to
gracefully handle failure anyways.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 virt/kvm/kvm_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f081839521ef..ae216256ee9d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4284,7 +4284,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id)
 
 	vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
 	r = xa_insert(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, GFP_KERNEL_ACCOUNT);
-	BUG_ON(r == -EBUSY);
+	WARN_ON_ONCE(r == -EBUSY);
 	if (r)
 		goto unlock_vcpu_destroy;
 
-- 
2.47.0.rc0.187.ge670bccf7e-goog