UBSAN: undefined-behaviour in tabledist

netlink: 12 bytes leftover after parsing attributes in process `syz-executor289'.
netlink: 12 bytes leftover after parsing attributes in process `syz-executor289'.
netlink: 12 bytes leftover after parsing attributes in process `syz-executor289'.
================================================================================
UBSAN: Undefined behaviour in net/sched/sch_netem.c:333:16
division by zero
CPU: 1 PID: 6515 Comm: syz-executor289 Not tainted 4.19.150-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x22c/0x33e lib/dump_stack.c:118
 ubsan_epilogue+0xe/0x3a lib/ubsan.c:161
 __ubsan_handle_divrem_overflow.cold+0xa4/0xcf lib/ubsan.c:257
 tabledist.part.0.cold+0x16/0x1b net/sched/sch_netem.c:333
 tabledist net/sched/sch_netem.c:534 [inline]
 netem_enqueue+0x45e/0x318a net/sched/sch_netem.c:534
 __dev_xmit_skb net/core/dev.c:3494 [inline]
 __dev_queue_xmit+0x14e1/0x2ec0 net/core/dev.c:3807
 neigh_resolve_output+0x55a/0x950 net/core/neighbour.c:1374
 neigh_output include/net/neighbour.h:501 [inline]
 ip6_finish_output2+0x1184/0x2370 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x610/0xcc0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x205/0x7c0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:455 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 mld_sendpack+0x6c1/0x1120 net/ipv6/mcast.c:1684
 mld_send_cr net/ipv6/mcast.c:1980 [inline]
 mld_ifc_timer_expire+0x616/0xc00 net/ipv6/mcast.c:2479
 call_timer_fn+0x177/0x760 kernel/time/timer.c:1338
 expire_timers+0x243/0x500 kernel/time/timer.c:1375
 __run_timers kernel/time/timer.c:1703 [inline]
 run_timer_softirq+0x259/0x730 kernel/time/timer.c:1716
 __do_softirq+0x27d/0xad2 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x22d/0x270 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:544 [inline]
 smp_apic_timer_interrupt+0x15f/0x5d0 arch/x86/kernel/apic/apic.c:1094
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline]
RIP: 0010:console_unlock+0xd82/0x1080 kernel/printk/printk.c:2468
Code: 89 48 c1 e8 03 42 80 3c 38 00 0f 85 e9 02 00 00 48 83 3d 08 79 08 08 00 0f 84 ce 00 00 00 e8 75 c1 16 00 48 8b 7c 24 18 57 9d <0f> 1f 44 00 00 e9 fb fc ff ff e8 5f c1 16 00 0f 0b 48 c7 c7 00 16
RSP: 0018:ffff8880a3f4eec8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffff8880a47c2140 RBX: 0000000000000200 RCX: 1ffff110148f8542
RDX: 0000000000000000 RSI: ffffffff815b10eb RDI: 0000000000000293
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000061
R13: ffffffff84ae3b60 R14: ffffffff8a6eec10 R15: dffffc0000000000
 vprintk_emit+0x2b8/0x7c0 kernel/printk/printk.c:1965
 vprintk_func+0x77/0x224 kernel/printk/printk_safe.c:397
 printk+0xba/0xed kernel/printk/printk.c:2040
 nla_parse.cold+0x26/0x37 lib/nlattr.c:267
 nla_parse_nested include/net/netlink.h:765 [inline]
 rtnl_newlink+0x3a3/0x15b0 net/core/rtnetlink.c:2987
 rtnetlink_rcv_msg+0x498/0xc10 net/core/rtnetlink.c:4778
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2455
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x717/0xcc0 net/netlink/af_netlink.c:1909
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xc7/0x130 net/socket.c:632
 ___sys_sendmsg+0x7bb/0x8f0 net/socket.c:2115
 __sys_sendmsg net/socket.c:2153 [inline]
 __do_sys_sendmsg net/socket.c:2162 [inline]
 __se_sys_sendmsg net/socket.c:2160 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2160
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441e19
Code: e8 1c b4 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 6b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd142df2a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441e19
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000402ba0 R14: 0000000000000000 R15: 0000000000000000
================================================================================
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 6515 Comm: syz-executor289 Not tainted 4.19.150-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tabledist.part.0+0x25f/0x320 net/sched/sch_netem.c:333
Code: fe ff ff e8 53 6b 36 fb 8d 5c 2d 00 31 ff 89 de e8 b6 6c 36 fb 85 db 0f 84 c9 44 00 00 e8 39 6b 36 fb 44 89 f0 31 d2 49 29 ec <f7> f3 49 01 d4 e9 15 ff ff ff e8 22 6b 36 fb 48 81 eb 00 10 00 00
RSP: 0018:ffff8880ae307518 EFLAGS: 00010207
RAX: 0000000099732b17 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff863b6727 RDI: 0000000000000001
RBP: ffffffff80000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000080000000
R13: ffff8880a3e850ac R14: 0000000099732b17 R15: 0000000000000000
FS:  0000000000715880(0000) GS:ffff8880ae300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000009e9af000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 tabledist net/sched/sch_netem.c:534 [inline]
 netem_enqueue+0x45e/0x318a net/sched/sch_netem.c:534
 __dev_xmit_skb net/core/dev.c:3494 [inline]
 __dev_queue_xmit+0x14e1/0x2ec0 net/core/dev.c:3807
 neigh_resolve_output+0x55a/0x950 net/core/neighbour.c:1374
 neigh_output include/net/neighbour.h:501 [inline]
 ip6_finish_output2+0x1184/0x2370 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x610/0xcc0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x205/0x7c0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:455 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 mld_sendpack+0x6c1/0x1120 net/ipv6/mcast.c:1684
 mld_send_cr net/ipv6/mcast.c:1980 [inline]
 mld_ifc_timer_expire+0x616/0xc00 net/ipv6/mcast.c:2479
 call_timer_fn+0x177/0x760 kernel/time/timer.c:1338
 expire_timers+0x243/0x500 kernel/time/timer.c:1375
 __run_timers kernel/time/timer.c:1703 [inline]
 run_timer_softirq+0x259/0x730 kernel/time/timer.c:1716
 __do_softirq+0x27d/0xad2 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x22d/0x270 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:544 [inline]
 smp_apic_timer_interrupt+0x15f/0x5d0 arch/x86/kernel/apic/apic.c:1094
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline]
RIP: 0010:console_unlock+0xd82/0x1080 kernel/printk/printk.c:2468
Code: 89 48 c1 e8 03 42 80 3c 38 00 0f 85 e9 02 00 00 48 83 3d 08 79 08 08 00 0f 84 ce 00 00 00 e8 75 c1 16 00 48 8b 7c 24 18 57 9d <0f> 1f 44 00 00 e9 fb fc ff ff e8 5f c1 16 00 0f 0b 48 c7 c7 00 16
RSP: 0018:ffff8880a3f4eec8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffff8880a47c2140 RBX: 0000000000000200 RCX: 1ffff110148f8542
RDX: 0000000000000000 RSI: ffffffff815b10eb RDI: 0000000000000293
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000061
R13: ffffffff84ae3b60 R14: ffffffff8a6eec10 R15: dffffc0000000000
 vprintk_emit+0x2b8/0x7c0 kernel/printk/printk.c:1965
 vprintk_func+0x77/0x224 kernel/printk/printk_safe.c:397
 printk+0xba/0xed kernel/printk/printk.c:2040
 nla_parse.cold+0x26/0x37 lib/nlattr.c:267
 nla_parse_nested include/net/netlink.h:765 [inline]
 rtnl_newlink+0x3a3/0x15b0 net/core/rtnetlink.c:2987
 rtnetlink_rcv_msg+0x498/0xc10 net/core/rtnetlink.c:4778
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2455
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x717/0xcc0 net/netlink/af_netlink.c:1909
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xc7/0x130 net/socket.c:632
 ___sys_sendmsg+0x7bb/0x8f0 net/socket.c:2115
 __sys_sendmsg net/socket.c:2153 [inline]
 __do_sys_sendmsg net/socket.c:2162 [inline]
 __se_sys_sendmsg net/socket.c:2160 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2160
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441e19
Code: e8 1c b4 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 6b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd142df2a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441e19
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000402ba0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace e3bbdaadbbdd9162 ]---
RIP: 0010:tabledist.part.0+0x25f/0x320 net/sched/sch_netem.c:333
Code: fe ff ff e8 53 6b 36 fb 8d 5c 2d 00 31 ff 89 de e8 b6 6c 36 fb 85 db 0f 84 c9 44 00 00 e8 39 6b 36 fb 44 89 f0 31 d2 49 29 ec <f7> f3 49 01 d4 e9 15 ff ff ff e8 22 6b 36 fb 48 81 eb 00 10 00 00
RSP: 0018:ffff8880ae307518 EFLAGS: 00010207
RAX: 0000000099732b17 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff863b6727 RDI: 0000000000000001
RBP: ffffffff80000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000080000000
R13: ffff8880a3e850ac R14: 0000000099732b17 R15: 0000000000000000
FS:  0000000000715880(0000) GS:ffff8880ae300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000009e9af000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2020/10/09 04:39	linux-4.19.y	a1b977b49b66	92390980	.config	console log	report	syz	C			ci2-linux-4-19
2020/10/09 03:40	linux-4.19.y	a1b977b49b66	92390980	.config	console log	report			info		ci2-linux-4-19