On Fri, Jul 03, 2020 at 11:15:31AM -0400, Woody Suwalski wrote: > I am observing a 100% reproducible kvm crash on kernels starting with > 5.7-rc1, always with the same opcode 0000. > It happens during wake up from the host suspended state. Worked OK on 5.6 > and older. > The host is based on Debian testing, Thinkpad T440, i5 cpu. > > [ 61.576664] kernel BUG at arch/x86/kvm/x86.c:387! > [ 61.576672] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI > [ 61.576678] CPU: 0 PID: 3851 Comm: qemu-system-x86 Not tainted 5.7-pingu > #0 > [ 61.576680] Hardware name: LENOVO 20B6005JUS/20B6005JUS, BIOS GJETA4WW > (2.54 ) 03/27/2020 > [ 61.576700] RIP: 0010:kvm_spurious_fault+0xa/0x10 [kvm] > > Crash results in a dead kvm and occasionally a very unstable system. > > Bisecting the problem between v5.6 and v5.7-rc1 points to > > commit 6650cdd9a8ccf00555dbbe743d58541ad8feb6a7 > Author: Peter Zijlstra (Intel) <pet...@infradead.org> > Date: Sun Jan 26 12:05:35 2020 -0800 > > x86/split_lock: Enable split lock detection by kernel > > Reversing that patch seems to actually "cure" the issue. > > The problem is present in all kernels past 5.7-rc1, however the patch is not > reversing directly in later source trees, so can not retest the logic on > recent kernels. > > Peter, would you have idea how to debug that (or even better - would you > happen to know the fix)? > > I have attached dmesg logs from a "good" 5.6.9 kernel, and then "bad" 5.7.0 > and 5.8-rc3
I have no clue about kvm. Nor do I actually have hardware with SLD on. I've Cc'ed a bunch of folks who might have more ideas.
