> On Apr 11, 2018, at 10:31 PM, Dario Faggioli <raist...@linux.it> wrote: > > Il Mer 11 Apr 2018, 22:48 Olaf Hering <o...@aepfle.de> ha scritto: > On Wed, Apr 11, Dario Faggioli wrote: > > > It will crash, again, possibly with the same stack trace, but I think > > it's worth a try. > > BUG_ON(__vcpu_on_runq(CSCHED_VCPU(vc))); > > (XEN) Xen BUG at sched_credit.c:876 > (XEN) ----[ Xen-4.11.20180410T125709.50f8ba84a5-7.bug1087289_411 x86_64 > debug=y Not tainted ]---- > (XEN) CPU: 108 > (XEN) RIP: e008:[<ffff82d080229ab4>] > sched_credit.c#csched_vcpu_migrate+0x27/0x54 > (XEN) RFLAGS: 0000000000010006 CONTEXT: hypervisor > ... > (XEN) Xen call trace: > (XEN) [<ffff82d080229ab4>] sched_credit.c#csched_vcpu_migrate+0x27/0x54 > (XEN) [<ffff82d080236348>] schedule.c#vcpu_move_locked+0xbb/0xc2 > (XEN) [<ffff82d08023764c>] schedule.c#vcpu_migrate+0x226/0x25b > (XEN) [<ffff82d080239367>] context_saved+0x95/0x9c > (XEN) [<ffff82d08027797d>] context_switch+0xe66/0xeb0 > (XEN) [<ffff82d080236943>] schedule.c#schedule+0x5f4/0x627 > (XEN) [<ffff82d080239f15>] softirq.c#__do_softirq+0x85/0x90 > (XEN) [<ffff82d080239f6a>] do_softirq+0x13/0x15 > (XEN) [<ffff82d08031f5db>] vmx_asm_do_vmentry+0x2b/0x30 > > So, really *exactly* the same. Ok, thanks.
But this doesn’t make any sense. If you applied Dario’s ‘fix’ patch, then context_saved() should have *just* called vcpu_sleep_nosync() before calling vcpu_migrate(). The VPF_migrating flag should still be set, so it should have called csched_vcpu_sleep(); and sd->curr should have been changed to be != prev way back in schedule(), so csched_vcpu_sleep() should have called runq_remove(). It’s probably worth asking the obvious question: Are you sure the “fix” patch is actually applied (in addition to the new “debug” patch)? :-) If so, then maybe it’s time to open-code vcpu_sleep_nosync() there in context_saved(), to try to figure out where our understanding of what *should* happen is incorrect. -George _______________________________________________ Xen-devel mailing list Xenfirstname.lastname@example.org https://lists.xenproject.org/mailman/listinfo/xen-devel