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? thanks, greg k-h -- 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>