On 02/11/2017 19:17, Andy Lutomirski wrote: > > >> On Nov 2, 2017, at 6:57 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: >> >>> On 02/11/2017 18:56, Nadav Amit wrote: >>> Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: >>> >>>>> On 02/11/2017 12:27, Ilya Lesokhin wrote: >>>>> Hi, >>>>> Just in case anyone is interested, I've hit a WARN_ON that shouldn't happen: >>>>> http://elixir.free-electrons.com/linux/v4.13.10/source/arch/x86/kernel/traps.c#L788 >>>>> >>>>> I was single stepping in GDB connected to a QEMU target >>>>> and got the trace below inside the VM. >>>>> >>>>> I'm not sure If it's a kernel bug or a KVM bug and I did try to reproduce or debug it. >>>>> >>>>> Hypervisor was running 3.10.0-514.21.1.el7.x86_64. >>>>> VM was running a modified 4.13.0. >>>> >>>> It's a KVM bug, though I'm not sure if it's easily fixable. >>> >>> What’s wrong with MTF? That’s what I used for debugging the Intel tests. >> >> Nothing, but I haven't checked if you might get the same failure on >> AMD---which doesn't have it. > > Is this that old SYSCALL CVE? No, he's just using QEMU's gdb server and bits of DR6 sometimes sneak into a guest that is e.g. using watchpoints. Paolo
