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authorPaolo Bonzini <pbonzini@redhat.com>2020-03-19 13:41:06 -0400
committerPaolo Bonzini <pbonzini@redhat.com>2020-03-20 13:43:21 -0400
commitd33294541889b023068522270cd4153ddd8e4635 (patch)
tree2d0fcb23c47dbfd49d49f4bae207590c56e6d6e3 /arch
parent018cabb694e3923998fdc2908af5268f1d89f48f (diff)
downloadlinux-d33294541889b023068522270cd4153ddd8e4635.tar.bz2
KVM: x86: remove bogus user-triggerable WARN_ON
The WARN_ON is essentially comparing a user-provided value with 0. It is trivial to trigger it just by passing garbage to KVM_SET_CLOCK. Guests can break if you do so, but the same applies to every KVM_SET_* ioctl. So, if it hurts when you do like this, just do not do it. Reported-by: syzbot+00be5da1d75f1cc95f6b@syzkaller.appspotmail.com Fixes: 9446e6fce0ab ("KVM: x86: fix WARN_ON check of an unsigned less than zero") Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/x86.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3156e25b0774..d65ff2008cf1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2444,7 +2444,6 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
vcpu->hv_clock.tsc_timestamp = tsc_timestamp;
vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
vcpu->last_guest_tsc = tsc_timestamp;
- WARN_ON((s64)vcpu->hv_clock.system_time < 0);
/* If the host uses TSC clocksource, then it is stable */
pvclock_flags = 0;