===================================== WARNING: bad unlock balance detected! 5.5.0-rc5-syzkaller #0 Not tainted ------------------------------------- syz-executor.1/2965 is trying to release lock (&dev->qdisc_xmit_lock_key) at: [] spin_unlock include/linux/spinlock.h:378 [inline] [] __netif_tx_unlock include/linux/netdevice.h:3969 [inline] [] sch_direct_xmit+0x3fa/0xd30 net/sched/sch_generic.c:315 but there are no more locks to release! other info that might help us debug this: 8 locks held by syz-executor.1/2965: #0: ffff8880a7007850 (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1516 [inline] #0: ffff8880a7007850 (sk_lock-AF_INET6){+.+.}, at: sctp_sendmsg+0x627/0x1f10 net/sctp/socket.c:1955 #1: ffffffff899a3f40 (rcu_read_lock){....}, at: sctp_v6_xmit+0x1f6/0x6a0 net/sctp/ipv6.c:214 #2: ffffffff899a3f00 (rcu_read_lock_bh){....}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #2: ffffffff899a3f00 (rcu_read_lock_bh){....}, at: ip6_finish_output2+0x214/0x25c0 net/ipv6/ip6_output.c:102 #3: ffffffff899a3f40 (rcu_read_lock){....}, at: ip6_nd_hdr net/ipv6/ndisc.c:463 [inline] #3: ffffffff899a3f40 (rcu_read_lock){....}, at: ndisc_send_skb+0x7fe/0x1490 net/ipv6/ndisc.c:499 #4: ffffffff899a3f00 (rcu_read_lock_bh){....}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #4: ffffffff899a3f00 (rcu_read_lock_bh){....}, at: ip6_finish_output2+0x214/0x25c0 net/ipv6/ip6_output.c:102 #5: ffffffff899a3f00 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x35c0 net/core/dev.c:3948 #6: ffff8880a9186250 (&dev->qdisc_tx_busylock_key#13){+...}, at: spin_trylock include/linux/spinlock.h:348 [inline] #6: ffff8880a9186250 (&dev->qdisc_tx_busylock_key#13){+...}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #6: ffff8880a9186250 (&dev->qdisc_tx_busylock_key#13){+...}, at: __dev_xmit_skb net/core/dev.c:3611 [inline] #6: ffff8880a9186250 (&dev->qdisc_tx_busylock_key#13){+...}, at: __dev_queue_xmit+0x2412/0x35c0 net/core/dev.c:3982 #7: ffff8880a9186138 (&dev->qdisc_running_key#13){+...}, at: dev_queue_xmit+0x18/0x20 net/core/dev.c:4046 stack backtrace: CPU: 1 PID: 2965 Comm: syz-executor.1 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_unlock_imbalance_bug kernel/locking/lockdep.c:4008 [inline] print_unlock_imbalance_bug.cold+0x114/0x123 kernel/locking/lockdep.c:3984 __lock_release kernel/locking/lockdep.c:4242 [inline] lock_release+0x5f2/0x960 kernel/locking/lockdep.c:4503 __raw_spin_unlock include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock+0x16/0x40 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:378 [inline] __netif_tx_unlock include/linux/netdevice.h:3969 [inline] sch_direct_xmit+0x3fa/0xd30 net/sched/sch_generic.c:315 __dev_xmit_skb net/core/dev.c:3621 [inline] __dev_queue_xmit+0x2707/0x35c0 net/core/dev.c:3982 dev_queue_xmit+0x18/0x20 net/core/dev.c:4046 neigh_resolve_output net/core/neighbour.c:1487 [inline] neigh_resolve_output+0x5c4/0x990 net/core/neighbour.c:1467 neigh_output include/net/neighbour.h:510 [inline] ip6_finish_output2+0x109a/0x25c0 net/ipv6/ip6_output.c:116 __ip6_finish_output+0x444/0xaa0 net/ipv6/ip6_output.c:142 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x25e/0x880 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0xf1f/0x1490 net/ipv6/ndisc.c:505 ndisc_send_ns+0x3a9/0x850 net/ipv6/ndisc.c:647 ndisc_solicit+0x2ed/0x470 net/ipv6/ndisc.c:739 neigh_probe+0xd0/0x120 net/core/neighbour.c:1009 __neigh_event_send+0x3e3/0x17c0 net/core/neighbour.c:1169 neigh_event_send include/net/neighbour.h:444 [inline] neigh_resolve_output+0x5ee/0x990 net/core/neighbour.c:1471 neigh_output include/net/neighbour.h:510 [inline] ip6_finish_output2+0x109a/0x25c0 net/ipv6/ip6_output.c:116 ip6_fragment+0x158b/0x2770 net/ipv6/ip6_output.c:919 __ip6_finish_output+0x577/0xaa0 net/ipv6/ip6_output.c:140 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x25e/0x880 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip6_xmit+0xe1a/0x2090 net/ipv6/ip6_output.c:279 sctp_v6_xmit+0x34b/0x6a0 net/sctp/ipv6.c:217 sctp_packet_transmit+0x1ba6/0x3740 net/sctp/output.c:629 sctp_packet_singleton net/sctp/outqueue.c:773 [inline] sctp_outq_flush_ctrl.constprop.0+0x73c/0xd30 net/sctp/outqueue.c:904 sctp_outq_flush+0xe8/0x2780 net/sctp/outqueue.c:1186 sctp_outq_uncork+0x6c/0x80 net/sctp/outqueue.c:758 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1793 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline] sctp_do_sm+0x50d/0x5330 net/sctp/sm_sideeffect.c:1156 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0xd14/0x22f0 net/sctp/socket.c:1826 sctp_sendmsg+0x1027/0x1f10 net/sctp/socket.c:2016 inet_sendmsg+0x9e/0xe0 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:672 __sys_sendto+0x262/0x380 net/socket.c:1998 __do_sys_sendto net/socket.c:2010 [inline] __se_sys_sendto net/socket.c:2006 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:2006 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b159 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f174cca9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f174ccaa6d4 RCX: 000000000045b159 RDX: 0000000000000001 RSI: 00000000200002c0 RDI: 0000000000000003 RBP: 000000000075c070 R08: 0000000020000300 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000009a7 R14: 00000000004caf69 R15: 000000000075c07c