linux-kernel - [PATCH] arch/powerpc/kvm: kvmppc_core_vcpu_create

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Message-Id: <20230323074718.2810914-1-kconsul@linux.vnet.ibm.com>
Date:   Thu, 23 Mar 2023 03:47:18 -0400
From:   Kautuk Consul <kconsul@...ux.vnet.ibm.com>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Fabiano Rosas <farosas@...ux.ibm.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Kautuk Consul <kconsul@...ux.vnet.ibm.com>
Subject: [PATCH] arch/powerpc/kvm: kvmppc_core_vcpu_create_hv: check for kzalloc failure

kvmppc_vcore_create() might not be able to allocate memory through
kzalloc. In that case the kvm->arch.online_vcores shouldn't be
incremented.
Add a check for kzalloc failure and return with -ENOMEM from
kvmppc_core_vcpu_create_hv().

Signed-off-by: Kautuk Consul <kconsul@...ux.vnet.ibm.com>
---
 arch/powerpc/kvm/book3s_hv.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190b..e29ee755c920 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2968,13 +2968,17 @@ static int kvmppc_core_vcpu_create_hv(struct kvm_vcpu *vcpu)
 			pr_devel("KVM: collision on id %u", id);
 			vcore = NULL;
 		} else if (!vcore) {
+			vcore = kvmppc_vcore_create(kvm,
+					id & ~(kvm->arch.smt_mode - 1));
+			if (unlikely(!vcore)) {
+				mutex_unlock(&kvm->lock);
+				return -ENOMEM;
+			}
+
 			/*
 			 * Take mmu_setup_lock for mutual exclusion
 			 * with kvmppc_update_lpcr().
 			 */
-			err = -ENOMEM;
-			vcore = kvmppc_vcore_create(kvm,
-					id & ~(kvm->arch.smt_mode - 1));
 			mutex_lock(&kvm->arch.mmu_setup_lock);
 			kvm->arch.vcores[core] = vcore;
 			kvm->arch.online_vcores++;
-- 
2.39.2