Am 21.03.2016 um 14:38 schrieb Greg KH: > On Mon, Mar 21, 2016 at 11:52:23AM +0100, Stefan Priebe - Profihost AG wrote: >> >> Am 20.03.2016 um 22:41 schrieb Greg KH: >>> On Sun, Mar 20, 2016 at 10:27:23PM +0100, Stefan Priebe wrote: >>>> >>>> Am 19.03.2016 um 23:26 schrieb Vlastimil Babka: >>>>> On 03/17/2016 07:45 PM, Greg KH wrote: >>>>>> On Thu, Mar 17, 2016 at 07:38:03PM +0100, Stefan Priebe wrote: >>>>>>> Hi, >>>>>>> >>>>>>> while running qemu 2.5 on a host running 4.4.6 the host system has >>>>>>> crashed >>>>>>> (load > 200) 3 times in the last 3 days. >>>>>>> >>>>>>> Always with this stack trace: (copy left here: >>>>>>> http://pastebin.com/raw/bCWTLKyt) >>>>>>> >>>>>>> [69068.874268] divide error: 0000 [#1] SMP >>>>>>> [69068.875242] Modules linked in: ebtable_filter ebtables ip6t_REJECT >>>>>>> nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter >>>>>>> ip6_tables >>>>>>> ipt_REJECT nf_reject_ipv4 xt_physdev xt_comment nf_conntrack_ipv4 >>>>>>> nf_defrag_ipv4 xt_tcpudp xt_mark xt_set xt_addrtype xt_conntrack >>>>>>> nf_conntrack ip_set_hash_net ip_set vhost_net tun vhost macvtap macvlan >>>>>>> kvm_intel nfnetlink_log kvm nfnetlink irqbypass netconsole dlm >>>>>>> xt_multiport >>>>>>> iptable_filter ip_tables x_tables iscsi_tcp libiscsi_tcp libiscsi >>>>>>> scsi_transport_iscsi nfsd auth_rpcgss oid_registry bonding coretemp >>>>>>> 8021q >>>>>>> garp fuse i2c_i801 i7core_edac edac_core i5500_temp button btrfs xor >>>>>>> raid6_pq dm_mod raid1 md_mod usb_storage ohci_hcd bcache sg usbhid >>>>>>> sd_mod >>>>>>> ata_generic uhci_hcd ehci_pci ehci_hcd usbcore ata_piix usb_common igb >>>>>>> i2c_algo_bit mpt3sas raid_class ixgbe scsi_transport_sas i2c_core >>>>>>> mdio ptp >>>>>>> pps_core >>>>>>> [69068.895604] CPU: 14 PID: 6673 Comm: ceph-osd Not tainted >>>>>>> 4.4.6+7-ph #1 >>>>>>> [69068.897052] Hardware name: Supermicro X8DT3/X8DT3, BIOS 2.1 >>>>>>> 03/17/2012 >>>>>>> [69068.898578] task: ffff880fc7f28000 ti: ffff880fda2c4000 task.ti: >>>>>>> ffff880fda2c4000 >>>>>>> [69068.900377] RIP: 0010:[<ffffffff860b372c>] [<ffffffff860b372c>] >>>>>>> task_h_load+0xcc/0x100 >>>>> >>>>> decodecode says: >>>>> >>>>> 27: 48 83 c1 01 add $0x1,%rcx >>>>> 2b:* 48 f7 f1 div %rcx <-- trapping >>>>> instruction >>>>> >>>>> This suggests the CONFIG_FAIR_GROUP_SCHED version of task_h_load: >>>>> >>>>> update_cfs_rq_h_load(cfs_rq); >>>>> return div64_ul(p->se.avg.load_avg * cfs_rq->h_load, >>>>> cfs_rq_load_avg(cfs_rq) + 1); >>>>> >>>>> So the load avg is -1, thus after adding 1 we get division by 0, huh? >>>> >>>> Yes CONFIG_FAIR_GROUP_SCHED is set. I cherry picked now all those commits up >>>> to 4.5 for fair.c: >>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/log/kernel/sched/fair.c?h=v4.5 >>>> >>>> It didn't happen again with v4.4.6 + 4.5 patches for fair.c >>> >>> Ok, that's a lot of patches, how about figuring out which single patch, >>> or shortest number of patches, makes things work again? >> >> will do so but it seems most out of those 9 patches are based on each >> other. So it wouldn't be easy. > > Worst case, we take all 9. Best case, we only need one :) Today i got another report from: casteven (at) gmail.com having the same issue. I wasn't able to figure out which of those 9 patches helps - i still can just tell that it does not happen with this series on top of 4.4. Stefan -- 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>