2017-01-17 14:51+0100, Dmitry Vyukov: > emulator_fix_hypercall() replaces hypercall with vmcall instruction, > but it does not handle GP exception properly when writes the new instruction. > It can return X86EMUL_PROPAGATE_FAULT without setting exception information. > This leads to incorrect emulation and triggers > WARN_ON(ctxt->exception.vector > 0x1f) in x86_emulate_insn() > as discovered by syzkaller fuzzer: > > WARNING: CPU: 2 PID: 18646 at arch/x86/kvm/emulate.c:5558 > Call Trace: > warn_slowpath_null+0x2c/0x40 kernel/panic.c:582 > x86_emulate_insn+0x16a5/0x4090 arch/x86/kvm/emulate.c:5572 > x86_emulate_instruction+0x403/0x1cc0 arch/x86/kvm/x86.c:5618 > emulate_instruction arch/x86/include/asm/kvm_host.h:1127 [inline] > handle_exception+0x594/0xfd0 arch/x86/kvm/vmx.c:5762 > vmx_handle_exit+0x2b7/0x38b0 arch/x86/kvm/vmx.c:8625 > vcpu_enter_guest arch/x86/kvm/x86.c:6888 [inline] > vcpu_run arch/x86/kvm/x86.c:6947 [inline] > > Set exception information when write in emulator_fix_hypercall() fails. > > Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> > Cc: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx > Cc: syzkaller@xxxxxxxxxxxxxxxx > --- Applied to kvm/master, thanks. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
