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From: Leonardo Bras <leonardo@linux.ibm.com>
To: kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org
Cc: Leonardo Bras <leonardo@linux.ibm.com>
Subject: [PATCH v2 1/4] powerpc/kvm/book3s: Fixes possible 'use after release' of kvm
Date: Thu,  7 Nov 2019 14:02:55 -0300
Message-ID: <20191107170258.36379-2-leonardo@linux.ibm.com> (raw)
In-Reply-To: <20191107170258.36379-1-leonardo@linux.ibm.com>

Fixes a possible 'use after free' of kvm variable in
kvm_vm_ioctl_create_spapr_tce, where it does a mutex_unlock(&kvm->lock)
after a kvm_put_kvm(kvm).

Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
 arch/powerpc/kvm/book3s_64_vio.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index 5834db0a54c6..a402ead833b6 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -316,14 +316,13 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
 
 	if (ret >= 0)
 		list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables);
-	else
-		kvm_put_kvm(kvm);
 
 	mutex_unlock(&kvm->lock);
 
 	if (ret >= 0)
 		return ret;
 
+	kvm_put_kvm(kvm);
 	kfree(stt);
  fail_acct:
 	account_locked_vm(current->mm, kvmppc_stt_pages(npages), false);
-- 
2.23.0


  reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07 17:02 [PATCH v2 0/4] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
2019-11-07 17:02 ` Leonardo Bras [this message]
2019-11-12  4:57   ` [PATCH v2 1/4] powerpc/kvm/book3s: Fixes possible 'use after release' of kvm Michael Ellerman
2019-11-14 18:43     ` Leonardo Bras
2019-11-21 13:24       ` Leonardo Bras
2019-11-07 17:02 ` [PATCH v2 2/4] powerpc/kvm/book3s: Replace current->mm by kvm->mm Leonardo Bras
2019-11-07 17:02 ` [PATCH v2 3/4] powerpc/kvm/book3e: " Leonardo Bras
2019-11-07 17:02 ` [PATCH v2 4/4] powerpc/kvm/e500: " Leonardo Bras

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