bisecting fixing commit since c3038e718a19fc596f7b1baba0f83d5146dc7784 building syzkaller on 25bb509e5964da8203766c4039e4fef25e4689b1 testing commit c3038e718a19fc596f7b1baba0f83d5146dc7784 with gcc (GCC) 8.1.0 kernel signature: e0aeffbd7e5d5fe9aa9f214b3247e0eef83393eae7c535e3a40cd3094479db06 all runs: crashed: divide error in tabledist testing current HEAD 357668399cf70ccdc0ee8967bff3448d0f4f9ae1 testing commit 357668399cf70ccdc0ee8967bff3448d0f4f9ae1 with gcc (GCC) 8.1.0 kernel signature: 10656d7cc056a06d5c9ccd229d2259efb636432daff67d8fca4392e00377b9be all runs: crashed: divide error in tabledist revisions tested: 2, total time: 24m33.167458341s (build: 17m13.487387023s, test: 6m24.55886543s) the crash still happens on HEAD commit msg: Linux 4.19.103 crash: divide error in tabledist IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready 8021q: adding VLAN 0 to HW filter on device batadv0 divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 7164 Comm: kworker/1:3 Not tainted 4.19.103-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:tabledist.part.18+0x10b/0x150 net/sched/sch_netem.c:333 Code: 3c 18 49 8d 80 ff 1f 00 00 49 0f 49 c0 48 83 c4 08 5b 48 c1 f8 0d 41 5c 48 01 f8 41 5d 5d c3 43 8d 4c 2d 00 31 d2 48 83 c4 08 f1 49 63 c5 48 29 c3 48 8d 04 1a 5b 41 5c 41 5d 5d c3 4c 89 e7 RSP: 0018:ffff88808f84ee48 EFLAGS: 00010286 RAX: 0000000057b6bb7a RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff86ff1660 RDI: ffffffff89a7f6e0 RBP: ffff88808f84ee60 R08: 0000000000000001 R09: ffffed10127615cd R10: ffffed10127615cd R11: ffff888093b0ae6b R12: 0000000000000000 R13: 0000000080000000 R14: ffff888093b0ad80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcef2d36000 CR3: 000000008bbe1000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tabledist net/sched/sch_netem.c:534 [inline] netem_enqueue+0x3b0/0x27a0 net/sched/sch_netem.c:534 __dev_xmit_skb net/core/dev.c:3496 [inline] __dev_queue_xmit+0x10ce/0x2a90 net/core/dev.c:3812 dev_queue_xmit+0xb/0x10 net/core/dev.c:3877 br_dev_queue_push_xmit+0x14b/0x590 net/bridge/br_forward.c:56 NF_HOOK include/linux/netfilter.h:289 [inline] br_forward_finish+0xdd/0x2f0 net/bridge/br_forward.c:69 NF_HOOK include/linux/netfilter.h:289 [inline] __br_forward+0x4d1/0x8d0 net/bridge/br_forward.c:113 deliver_clone+0x54/0xa0 net/bridge/br_forward.c:129 maybe_deliver net/bridge/br_forward.c:184 [inline] br_flood+0x3a4/0x580 net/bridge/br_forward.c:226 br_dev_xmit+0xc5c/0x1210 net/bridge/br_device.c:103 __netdev_start_xmit include/linux/netdevice.h:4314 [inline] netdev_start_xmit include/linux/netdevice.h:4323 [inline] xmit_one net/core/dev.c:3258 [inline] dev_hard_start_xmit+0x160/0x6f0 net/core/dev.c:3274 __dev_queue_xmit+0x2135/0x2a90 net/core/dev.c:3844 dev_queue_xmit+0xb/0x10 net/core/dev.c:3877 neigh_hh_output include/net/neighbour.h:491 [inline] neigh_output include/net/neighbour.h:499 [inline] ip6_finish_output2+0xf33/0x2310 net/ipv6/ip6_output.c:120 ip6_finish_output+0x3c4/0xa90 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x1bf/0x660 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:447 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] mld_sendpack+0x87c/0xcd0 net/ipv6/mcast.c:1684 mld_send_initial_cr.part.32+0xd7/0x110 net/ipv6/mcast.c:2101 mld_send_initial_cr net/ipv6/mcast.c:2114 [inline] ipv6_mc_dad_complete+0x14d/0x1a0 net/ipv6/mcast.c:2108 addrconf_dad_completed+0x86f/0xbb0 net/ipv6/addrconf.c:4122 addrconf_dad_work+0x652/0xfc0 net/ipv6/addrconf.c:4053 process_one_work+0x830/0x1670 kernel/workqueue.c:2153 worker_thread+0x85/0xb60 kernel/workqueue.c:2296 kthread+0x324/0x3e0 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Modules linked in: ---[ end trace a0270aac0743077e ]--- RIP: 0010:tabledist.part.18+0x10b/0x150 net/sched/sch_netem.c:333 Code: 3c 18 49 8d 80 ff 1f 00 00 49 0f 49 c0 48 83 c4 08 5b 48 c1 f8 0d 41 5c 48 01 f8 41 5d 5d c3 43 8d 4c 2d 00 31 d2 48 83 c4 08 f1 49 63 c5 48 29 c3 48 8d 04 1a 5b 41 5c 41 5d 5d c3 4c 89 e7 RSP: 0018:ffff88808f84ee48 EFLAGS: 00010286 RAX: 0000000057b6bb7a RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff86ff1660 RDI: ffffffff89a7f6e0 RBP: ffff88808f84ee60 R08: 0000000000000001 R09: ffffed10127615cd R10: ffffed10127615cd R11: ffff888093b0ae6b R12: 0000000000000000 R13: 0000000080000000 R14: ffff888093b0ad80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcef2d36000 CR3: 000000008bbe1000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400