Just so it doesn't get lost. In XenRT, we've found:
> (XEN) ----[ Xen-4.19.0-1-d x86_64 debug=y Tainted: H ]----
> (XEN) CPU: 45
> (XEN) RIP: e008:[<ffff82d040244cbf>]
> common/sched/credit.c#csched_load_balance+0x41/0x877
> (XEN) RFLAGS: 0000000000010092 CONTEXT: hypervisor
> (XEN) rax: ffff82d040981618 rbx: ffff82d040981618 rcx:
> 0000000000000000
> (XEN) rdx: 0000003ff68cd000 rsi: 000000000000002d rdi:
> ffff83103723d450
> (XEN) rbp: ffff83207caa7d48 rsp: ffff83207caa7b98 r8:
> 0000000000000000
> (XEN) r9: ffff831037253cf0 r10: ffff83103767c3f0 r11:
> 0000000000000009
> (XEN) r12: ffff831037237990 r13: ffff831037237990 r14:
> ffff831037253720
> (XEN) r15: 0000000000000000 cr0: 000000008005003b cr4:
> 0000000000f526e0
> (XEN) cr3: 000000005bc2f000 cr2: 0000000000000010
> (XEN) fsb: 0000000000000000 gsb: 0000000000000000 gss:
> 0000000000000000
> (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0000 cs: e008
> (XEN) Xen code around <ffff82d040244cbf>
> (common/sched/credit.c#csched_load_balance+0x41/0x877):
> (XEN) 48 8b 0c 10 48 8b 49 08 <48> 8b 79 10 48 89 bd b8 fe ff ff 49
> 8b 4e 28 48
> <snip>
> (XEN) Xen call trace:
> (XEN) [<ffff82d040244cbf>] R
> common/sched/credit.c#csched_load_balance+0x41/0x877
> (XEN) [<ffff82d040245a18>] F
> common/sched/credit.c#csched_schedule+0x36a/0x69f
> (XEN) [<ffff82d040252644>] F common/sched/core.c#do_schedule+0xe8/0x433
> (XEN) [<ffff82d0402572dd>] F common/sched/core.c#schedule+0x2e5/0x2f9
> (XEN) [<ffff82d040232f35>] F common/softirq.c#__do_softirq+0x94/0xbe
> (XEN) [<ffff82d040232fc8>] F do_softirq+0x13/0x15
> (XEN) [<ffff82d0403075ef>] F arch/x86/domain.c#idle_loop+0x92/0xe6
> (XEN)
> (XEN) Pagetable walk from 0000000000000010:
> (XEN) L4[0x000] = 000000103ffca063 ffffffffffffffff
> (XEN) L3[0x000] = 000000103ffc9063 ffffffffffffffff
> (XEN) L2[0x000] = 000000103ffc8063 ffffffffffffffff
> (XEN) L1[0x000] = 0000000000000000 ffffffffffffffff
> (XEN)
> (XEN) ****************************************
> (XEN) Panic on CPU 45:
> (XEN) FATAL PAGE FAULT
> (XEN) [error_code=0000]
> (XEN) Faulting linear address: 0000000000000010
> (XEN) ****************************************
which we can reproduce reliably enough with a shell script doing
xen-hptool cpu-{off,on}line.
~Andrew
