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author | Greg Kurz <groug@kaod.org> | 2017-09-15 00:56:25 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-02 11:54:45 +0300 |
commit | 3f3414599f110c8dce4e0b0d51502fc8c07517d7 (patch) | |
tree | 4507a8756eb3ceaf0b98517ee640c5e359631bce /arch | |
parent | 5388b61da09c600e3980c18870c7767116de1482 (diff) | |
download | linux-3f3414599f110c8dce4e0b0d51502fc8c07517d7.tar.xz |
KVM: PPC: Fix oops when checking KVM_CAP_PPC_HTM
commit ac64115a66c18c01745bbd3c47a36b124e5fd8c0 upstream.
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")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/powerpc/kvm/powerpc.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 1a75c0b5f4ca..86468190d4b2 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -639,8 +639,7 @@ 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; |