bond6: (slave gretap2): making interface the new active one ============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.4.58605/8883 is trying to acquire lock: ffff88801d2cf318 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] ffff88801d2cf318 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4186 [inline] ffff88801d2cf318 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_queue_xmit+0xd58/0x3b70 net/core/dev.c:4729 but task is already holding lock: ffff88803666c398 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:197 [inline] ffff88803666c398 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4139 [inline] ffff88803666c398 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_queue_xmit+0x1370/0x3b70 net/core/dev.c:4729 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3); *** DEADLOCK *** May be due to missing lock nesting notation 15 locks held by syz.4.58605/8883: #0: ffffffff8ed7b530 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ed7b530 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8ed7b530 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8e8635b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8e8635b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8e8635b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064 #2: ffffffff8d44aca0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0xa1/0x540 kernel/softirq.c:163 #3: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0xa1/0x540 kernel/softirq.c:163 #4: ffffffff8d5aa8e0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #4: ffffffff8d5aa8e0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline] #4: ffffffff8d5aa8e0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x26f/0x3b70 net/core/dev.c:4688 #5: ffff88803666c398 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:197 [inline] #5: ffff88803666c398 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4139 [inline] #5: ffff88803666c398 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_queue_xmit+0x1370/0x3b70 net/core/dev.c:4729 #6: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #6: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #6: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_trylock kernel/locking/spinlock_rt.c:110 [inline] #6: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rt_spin_trylock+0x10d/0x2b0 kernel/locking/spinlock_rt.c:118 #7: ffff88804804fd98 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] #7: ffff88804804fd98 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4685 [inline] #7: ffff88804804fd98 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: sch_direct_xmit+0x153/0x4b0 net/sched/sch_generic.c:345 #8: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #8: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #8: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #8: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1c1/0x3e0 kernel/locking/spinlock_rt.c:57 #9: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #9: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #9: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5b/0x450 net/ipv4/ip_output.c:433 #10: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #10: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #10: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x452/0x11d0 net/ipv4/ip_output.c:230 #11: ffffffff8d44aca0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0xa1/0x540 kernel/softirq.c:163 #12: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #12: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #12: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: arp_xmit+0x23/0x270 net/ipv4/arp.c:662 #13: ffffffff8d44aca0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0xa1/0x540 kernel/softirq.c:163 #14: ffffffff8d5aa8e0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #14: ffffffff8d5aa8e0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline] #14: ffffffff8d5aa8e0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x26f/0x3b70 net/core/dev.c:4688 stack backtrace: CPU: 0 UID: 0 PID: 8883 Comm: syz.4.58605 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] __dev_xmit_skb net/core/dev.c:4186 [inline] __dev_queue_xmit+0xd58/0x3b70 net/core/dev.c:4729 NF_HOOK+0x310/0x3a0 include/linux/netfilter.h:-1 arp_xmit+0x16c/0x270 net/ipv4/arp.c:664 arp_solicit+0xc6a/0xeb0 net/ipv4/arp.c:392 neigh_probe net/core/neighbour.c:1098 [inline] __neigh_event_send+0xf68/0x1580 net/core/neighbour.c:1271 neigh_event_send_probe include/net/neighbour.h:471 [inline] neigh_event_send include/net/neighbour.h:477 [inline] neigh_resolve_output+0x19f/0x780 net/core/neighbour.c:1579 neigh_output include/net/neighbour.h:547 [inline] ip_finish_output2+0xd97/0x11d0 net/ipv4/ip_output.c:237 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:438 iptunnel_xmit+0x5f8/0xa90 net/ipv4/ip_tunnel_core.c:84 ip_tunnel_xmit+0x1c44/0x2390 net/ipv4/ip_tunnel.c:845 __gre_xmit net/ipv4/ip_gre.c:488 [inline] gre_tap_xmit+0x590/0x7a0 net/ipv4/ip_gre.c:776 __netdev_start_xmit include/linux/netdevice.h:5248 [inline] netdev_start_xmit include/linux/netdevice.h:5257 [inline] xmit_one net/core/dev.c:3845 [inline] dev_hard_start_xmit+0x2f0/0x870 net/core/dev.c:3861 sch_direct_xmit+0x241/0x4b0 net/sched/sch_generic.c:347 __dev_xmit_skb net/core/dev.c:4152 [inline] __dev_queue_xmit+0x1826/0x3b70 net/core/dev.c:4729 dev_queue_xmit include/linux/netdevice.h:3365 [inline] alb_send_lp_vid+0x324/0x510 drivers/net/bonding/bond_alb.c:949 alb_send_learning_packets+0x10d/0x2c0 drivers/net/bonding/bond_alb.c:1012 bond_alb_handle_active_change+0xa1b/0xed0 drivers/net/bonding/bond_alb.c:1779 bond_change_active_slave+0x1084/0x37f0 drivers/net/bonding/bond_main.c:1256 bond_select_active_slave+0x8e2/0xd00 drivers/net/bonding/bond_main.c:1336 bond_enslave+0x21a8/0x38a0 drivers/net/bonding/bond_main.c:2286 do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2956 rtnl_newlink_create+0x677/0xb00 net/core/rtnetlink.c:3847 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x16e4/0x1c80 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x846/0xa10 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x508/0x820 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x1a1/0x260 net/socket.c:2719 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f52c743f6c9 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:00007f52c569e038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f52c7695fa0 RCX: 00007f52c743f6c9 RDX: 0000000000000040 RSI: 00002000000000c0 RDI: 0000000000000008 RBP: 00007f52c74c1f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f52c7696038 R14: 00007f52c7695fa0 R15: 00007ffdd4d46168 bond6: (slave gretap2): Enslaving as an active interface with an up link syz.4.58605 (8883) used greatest stack depth: 15912 bytes left