Messages in this thread | | | Subject | Re: kvm crash on 5.7-rc1 and later | From | Woody Suwalski <> | Date | Sun, 12 Jul 2020 07:54:23 -0400 |
| |
Xiaoyao Li wrote: > On 7/12/2020 2:21 AM, Peter Zijlstra wrote: >> 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) <peterz@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. >> > > I think this bug is the same as the one found by Sean, and is already > fixed in 5.8-rc4. > > https://lore.kernel.org/kvm/20200605192605.7439-1-sean.j.christopherson@intel.com/ >
You are right, kvm works OK on 5.8-rc4. The fix will need to be backported to 5.7.
Thanks, Woody
| |