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From: Christian Borntraeger <borntraeger@linux.ibm.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: KVM <kvm@vger.kernel.org>, Janosch Frank <frankja@linux.ibm.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	David Hildenbrand <david@redhat.com>,
	linux-s390 <linux-s390@vger.kernel.org>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Thomas Huth <thuth@redhat.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>
Subject: [GIT PULL 1/1] KVM: s390: Check kvm pointer when testing KVM_CAP_S390_HPAGE_1M
Date: Tue,  7 May 2024 14:29:45 +0200	[thread overview]
Message-ID: <20240507122945.2571-2-borntraeger@linux.ibm.com> (raw)
In-Reply-To: <20240507122945.2571-1-borntraeger@linux.ibm.com>

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

KVM allows issuing the KVM_CHECK_EXTENSION ioctl either on the /dev/kvm
fd or the VM fd. In the first case, kvm_vm_ioctl_check_extension() is
called with kvm==NULL. Ensure we don't dereference the pointer in that
case.

Fixes: 40ebdb8e59df ("KVM: s390: Make huge pages unavailable in ucontrol VMs")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Message-ID: <20240419160723.320910-2-jean-philippe@linaro.org>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
---
 arch/s390/kvm/kvm-s390.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 5147b943a864..7721eb522f43 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -587,7 +587,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		break;
 	case KVM_CAP_S390_HPAGE_1M:
 		r = 0;
-		if (hpage && !kvm_is_ucontrol(kvm))
+		if (hpage && !(kvm && kvm_is_ucontrol(kvm)))
 			r = 1;
 		break;
 	case KVM_CAP_S390_MEM_OP:
-- 
2.44.0


  reply	other threads:[~2024-05-07 12:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-07 12:29 [GIT PULL 0/1] KVM: s390: Fix for 6.9 Christian Borntraeger
2024-05-07 12:29 ` Christian Borntraeger [this message]
2024-05-07 17:01 ` Paolo Bonzini

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