====================================================== WARNING: possible circular locking dependency detected 6.16.0-rc6-syzkaller-00037-ge2291551827f #0 Not tainted ------------------------------------------------------ syz.2.12444/32564 is trying to acquire lock: ffff88802b7e4a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88802b7e4a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4136 [inline] ffff88802b7e4a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}, at: __dev_queue_xmit+0x334c/0x43e0 net/core/dev.c:4679 but task is already holding lock: ffff888033dd2558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888033dd2558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4651 [inline] ffff888033dd2558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x3ba/0xcf0 net/sched/sch_generic.c:342 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4651 [inline] sch_direct_xmit+0x3ba/0xcf0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:4102 [inline] __dev_queue_xmit+0x13c7/0x43e0 net/core/dev.c:4679 dev_queue_xmit include/linux/netdevice.h:3355 [inline] neigh_resolve_output net/core/neighbour.c:1512 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1492 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xaeb/0x2020 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:306 [inline] ip6_output+0x1f9/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] NF_HOOK include/linux/netfilter.h:311 [inline] mld_sendpack+0x9e9/0x1220 net/ipv6/mcast.c:1868 mld_send_cr net/ipv6/mcast.c:2169 [inline] mld_ifc_work+0x740/0xca0 net/ipv6/mcast.c:2702 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}: check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:4136 [inline] __dev_queue_xmit+0x334c/0x43e0 net/core/dev.c:4679 dev_queue_xmit include/linux/netdevice.h:3355 [inline] neigh_resolve_output net/core/neighbour.c:1512 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1492 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xaeb/0x2020 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:306 [inline] ip6_output+0x1f9/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] ip6_local_out+0xcd/0x4a0 net/ipv6/output_core.c:155 ip6_send_skb+0x112/0x460 net/ipv6/ip6_output.c:1982 ip6_push_pending_frames+0xe0/0x110 net/ipv6/ip6_output.c:2003 icmpv6_push_pending_frames+0x2dc/0x460 net/ipv6/icmp.c:311 icmp6_send+0x1ec9/0x2be0 net/ipv6/icmp.c:632 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x31/0x5a0 net/ipv6/route.c:2843 dst_link_failure include/net/dst.h:429 [inline] ip_tunnel_xmit+0x2fb0/0x37b0 net/ipv4/ip_tunnel.c:865 __gre_xmit+0x8bb/0xc00 net/ipv4/ip_gre.c:488 erspan_xmit+0x56b/0x25d0 net/ipv4/ip_gre.c:747 __netdev_start_xmit include/linux/netdevice.h:5215 [inline] netdev_start_xmit include/linux/netdevice.h:5224 [inline] xmit_one net/core/dev.c:3830 [inline] dev_hard_start_xmit+0x97/0x740 net/core/dev.c:3846 sch_direct_xmit+0x1b2/0xcf0 net/sched/sch_generic.c:344 qdisc_restart net/sched/sch_generic.c:409 [inline] __qdisc_run+0x541/0x1bf0 net/sched/sch_generic.c:417 __dev_xmit_skb net/core/dev.c:4171 [inline] __dev_queue_xmit+0x2aa4/0x43e0 net/core/dev.c:4679 dev_queue_xmit include/linux/netdevice.h:3355 [inline] neigh_resolve_output net/core/neighbour.c:1512 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1492 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xaeb/0x2020 net/ipv6/ip6_output.c:141 ip6_fragment+0xbf2/0x27f0 net/ipv6/ip6_output.c:1028 __ip6_finish_output net/ipv6/ip6_output.c:213 [inline] ip6_finish_output+0x395/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:306 [inline] ip6_output+0x1f9/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] NF_HOOK include/linux/netfilter.h:311 [inline] ip6_xmit+0x12d7/0x2320 net/ipv6/ip6_output.c:366 sctp_v6_xmit+0xcab/0x11a0 net/sctp/ipv6.c:248 sctp_packet_transmit+0x1ef9/0x3040 net/sctp/output.c:653 sctp_packet_singleton+0x19e/0x370 net/sctp/outqueue.c:783 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x53d/0x3350 net/sctp/outqueue.c:1212 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1824 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1204 [inline] sctp_do_sm+0x1792/0x5c80 net/sctp/sm_sideeffect.c:1175 sctp_primitive_ASSOCIATE+0x9c/0xd0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0xa45/0x1bf0 net/sctp/socket.c:1842 sctp_sendmsg+0xef5/0x1ee0 net/sctp/socket.c:2032 inet_sendmsg+0x119/0x140 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0x973/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmmsg+0x200/0x420 net/socket.c:2709 __do_sys_sendmmsg net/socket.c:2736 [inline] __se_sys_sendmmsg net/socket.c:2733 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2733 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&qdisc_xmit_lock_key#4); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2); lock(&qdisc_xmit_lock_key#4); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2); *** DEADLOCK *** 10 locks held by syz.2.12444/32564: #0: ffff888047e994d8 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff888047e994d8 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_sendmsg+0xd8c/0x1ee0 net/sctp/socket.c:1971 #1: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: sctp_v6_xmit+0xbac/0x11a0 net/sctp/ipv6.c:247 #2: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #2: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #2: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x39d/0x2020 net/ipv6/ip6_output.c:126 #3: ffffffff8e5c4da0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8e5c4da0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline] #3: ffffffff8e5c4da0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x276/0x43e0 net/core/dev.c:4638 #4: ffff888033dd2558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff888033dd2558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4651 [inline] #4: ffff888033dd2558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x3ba/0xcf0 net/sched/sch_generic.c:342 #5: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #5: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #5: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: icmp6_send+0x24c/0x2be0 net/ipv6/icmp.c:477 #6: ffff888109ec8998 (k-slock-AF_INET6){+.-.}-{3:3}, at: spin_trylock include/linux/spinlock.h:361 [inline] #6: ffff888109ec8998 (k-slock-AF_INET6){+.-.}-{3:3}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #6: ffff888109ec8998 (k-slock-AF_INET6){+.-.}-{3:3}, at: icmp6_send+0x8a5/0x2be0 net/ipv6/icmp.c:554 #7: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #7: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #7: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: ip6_send_skb+0xb9/0x460 net/ipv6/ip6_output.c:1981 #8: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #8: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #8: ffffffff8e5c4e00 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x39d/0x2020 net/ipv6/ip6_output.c:126 #9: ffffffff8e5c4da0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8e5c4da0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline] #9: ffffffff8e5c4da0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x276/0x43e0 net/core/dev.c:4638 stack backtrace: CPU: 1 UID: 0 PID: 32564 Comm: syz.2.12444 Not tainted 6.16.0-rc6-syzkaller-00037-ge2291551827f #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:4136 [inline] __dev_queue_xmit+0x334c/0x43e0 net/core/dev.c:4679 dev_queue_xmit include/linux/netdevice.h:3355 [inline] neigh_resolve_output net/core/neighbour.c:1512 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1492 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xaeb/0x2020 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:306 [inline] ip6_output+0x1f9/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] ip6_local_out+0xcd/0x4a0 net/ipv6/output_core.c:155 ip6_send_skb+0x112/0x460 net/ipv6/ip6_output.c:1982 ip6_push_pending_frames+0xe0/0x110 net/ipv6/ip6_output.c:2003 icmpv6_push_pending_frames+0x2dc/0x460 net/ipv6/icmp.c:311 icmp6_send+0x1ec9/0x2be0 net/ipv6/icmp.c:632 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x31/0x5a0 net/ipv6/route.c:2843 dst_link_failure include/net/dst.h:429 [inline] ip_tunnel_xmit+0x2fb0/0x37b0 net/ipv4/ip_tunnel.c:865 __gre_xmit+0x8bb/0xc00 net/ipv4/ip_gre.c:488 erspan_xmit+0x56b/0x25d0 net/ipv4/ip_gre.c:747 __netdev_start_xmit include/linux/netdevice.h:5215 [inline] netdev_start_xmit include/linux/netdevice.h:5224 [inline] xmit_one net/core/dev.c:3830 [inline] dev_hard_start_xmit+0x97/0x740 net/core/dev.c:3846 sch_direct_xmit+0x1b2/0xcf0 net/sched/sch_generic.c:344 qdisc_restart net/sched/sch_generic.c:409 [inline] __qdisc_run+0x541/0x1bf0 net/sched/sch_generic.c:417 __dev_xmit_skb net/core/dev.c:4171 [inline] __dev_queue_xmit+0x2aa4/0x43e0 net/core/dev.c:4679 dev_queue_xmit include/linux/netdevice.h:3355 [inline] neigh_resolve_output net/core/neighbour.c:1512 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1492 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xaeb/0x2020 net/ipv6/ip6_output.c:141 ip6_fragment+0xbf2/0x27f0 net/ipv6/ip6_output.c:1028 __ip6_finish_output net/ipv6/ip6_output.c:213 [inline] ip6_finish_output+0x395/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:306 [inline] ip6_output+0x1f9/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] NF_HOOK include/linux/netfilter.h:311 [inline] ip6_xmit+0x12d7/0x2320 net/ipv6/ip6_output.c:366 sctp_v6_xmit+0xcab/0x11a0 net/sctp/ipv6.c:248 sctp_packet_transmit+0x1ef9/0x3040 net/sctp/output.c:653 sctp_packet_singleton+0x19e/0x370 net/sctp/outqueue.c:783 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x53d/0x3350 net/sctp/outqueue.c:1212 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1824 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1204 [inline] sctp_do_sm+0x1792/0x5c80 net/sctp/sm_sideeffect.c:1175 sctp_primitive_ASSOCIATE+0x9c/0xd0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0xa45/0x1bf0 net/sctp/socket.c:1842 sctp_sendmsg+0xef5/0x1ee0 net/sctp/socket.c:2032 inet_sendmsg+0x119/0x140 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0x973/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmmsg+0x200/0x420 net/socket.c:2709 __do_sys_sendmmsg net/socket.c:2736 [inline] __se_sys_sendmmsg net/socket.c:2733 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2733 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6a3b18e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6a3c097038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f6a3b3b5fa0 RCX: 00007f6a3b18e929 RDX: 0000000000000002 RSI: 0000200000000800 RDI: 0000000000000003 RBP: 00007f6a3b210ca1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000014 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6a3b3b5fa0 R15: 00007ffd5dac50b8 syz.2.12444 (32564) used greatest stack depth: 18640 bytes left