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authorGreg Kurz <groug@kaod.org>2017-09-14 23:56:25 +0200
committerPaul Mackerras <paulus@ozlabs.org>2017-10-14 11:32:53 +1100
commitac64115a66c18c01745bbd3c47a36b124e5fd8c0 (patch)
treeb58e717d09ba7479189c8ee37f8d819f38348f51 /arch
parent8a5776a5f49812d29fe4b2d0a2d71675c3facf3f (diff)
KVM: PPC: Fix oops when checking KVM_CAP_PPC_HTM
The following program causes a kernel oops: #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/ioctl.h> #include <linux/kvm.h> main() { int fd = open("/dev/kvm", O_RDWR); ioctl(fd, KVM_CHECK_EXTENSION, KVM_CAP_PPC_HTM); } This happens because when using the global KVM fd with KVM_CHECK_EXTENSION, kvm_vm_ioctl_check_extension() gets called with a NULL kvm argument, which gets dereferenced in is_kvmppc_hv_enabled(). Spotted while reading the code. Let's use the hv_enabled fallback variable, like everywhere else in this function. Fixes: 23528bb21ee2 ("KVM: PPC: Introduce KVM_CAP_PPC_HTM") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kvm/powerpc.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 3480faaf1ef8..ee279c7f4802 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -644,8 +644,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
break;
#endif
case KVM_CAP_PPC_HTM:
- r = cpu_has_feature(CPU_FTR_TM_COMP) &&
- is_kvmppc_hv_enabled(kvm);
+ r = cpu_has_feature(CPU_FTR_TM_COMP) && hv_enabled;
break;
default:
r = 0;