On Thu 13-06-13 16:57:23, Richard Weinberger wrote: > Am 13.06.2013 16:45, schrieb Richard Weinberger: > >Am 13.06.2013 16:39, schrieb Michal Hocko: > >>On Thu 13-06-13 15:34:59, Richard Weinberger wrote: > >>>Am 13.06.2013 15:32, schrieb Michal Hocko: > >>>>Ohh and could you post the config please? Sorry should have asked > >>>>earlier. > >>> > >>>See attachment. > >> > >>Nothing unusual there. Could you enable CONFIG_DEBUG_VM maybe it will > >>help too catch the problem earlier. > > > >OK > > > >>>>On Thu 13-06-13 15:29:08, Michal Hocko wrote: > >>>>> > >>>>>On Thu 13-06-13 14:06:20, Richard Weinberger wrote: > >>>>>[...] > >>>>>>All code > >>>>>>======== > >>>>>> 0: 89 50 08 mov %edx,0x8(%rax) > >>>>>> 3: 48 89 d1 mov %rdx,%rcx > >>>>>> 6: 0f 1f 40 00 nopl 0x0(%rax) > >>>>>> a: 49 8b 04 24 mov (%r12),%rax > >>>>>> e: 48 89 c2 mov %rax,%rdx > >>>>>> 11: 48 c1 e8 38 shr $0x38,%rax > >>>>>> 15: 83 e0 03 and $0x3,%eax > >>>>> nid = page_to_nid > >>>>>> 18: 48 c1 ea 3a shr $0x3a,%rdx > >>>>> zid = page_zonenum > >> > >>Ohh, I am wrong here. rdx should be nid and eax the zid. > >> > >>>>> > >>>>>> 1c: 48 69 c0 38 01 00 00 imul $0x138,%rax,%rax > >>>>>> 23: 48 03 84 d1 e0 02 00 add 0x2e0(%rcx,%rdx,8),%rax > >>>>> &memcg->nodeinfo[nid]->zoneinfo[zid] > >>>>> > >>>>>> 2a: 00 > >>>>>> 2b:* 48 3b 58 70 cmp 0x70(%rax),%rbx <-- trapping instruction > >>>>> > >>>>>OK, so this maps to: > >>>>> if (unlikely(lruvec->zone != zone)) <<< > >>>>> lruvec->zone = zone; > >>>>> > >>>>>>[35355.883056] RSP: 0000:ffff88003d523aa8 EFLAGS: 00010002 > >>>>>>[35355.883056] RAX: 0000000000000138 RBX: ffff88003fffa600 RCX: ffff88003e04a800 > >>>>>>[35355.883056] RDX: 0000000000000020 RSI: 0000000000000000 RDI: 0000000000028500 > >>>>>>[35355.883056] RBP: ffff88003d523ab8 R08: 0000000000000000 R09: 0000000000000000 > >>>>>>[35355.883056] R10: 0000000000000000 R11: dead000000100100 R12: ffffea0000a14000 > >>>>>>[35355.883056] R13: ffff88003e04b138 R14: ffff88003d523bb8 R15: ffffea0000a14020 > >>>>>>[35355.883056] FS: 0000000000000000(0000) GS:ffff88003fd80000(0000) > >>>>> > >>>>>RAX (lruvec) is obviously incorrect and it doesn't make any sense. rax should > >>>>>contain an address at an offset from ffff88003e04a800 But there is 0x138 there > >>>>>instead. > >> > >>Hmm, now that I am looking at the registers again. RDX which should be > >>nid seems to be quite big. It says this is node 32. Does the machine > >>have really so many NUMA nodes? > > > >No. It's a KVM guest with two CPUs. Nothing special. > >qemu command line: > >qemu-kvm -m 1G -drive file=lxc_host.qcow2,if=virtio -nographic -kernel linux/arch/x86/boot/bzImage -append console=ttyS0 root=/dev/vda2 -net user,hostfwd=tcp::5555-:22 -net > >nic,model=e1000 -smp 4 OK, then something probably overwrites page->flags. I would be more inclined to blame some other code ;) Maybe DEBUG_VM will start shouting earlier > Errr, I meant four CPUs. :) -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>