============================================ WARNING: possible recursive locking detected 6.1.127-syzkaller #0 Not tainted -------------------------------------------- kworker/u4:13/6537 is trying to acquire lock: ffff88807a528a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88807a528a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3894 [inline] ffff88807a528a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x22db/0x3d50 net/core/dev.c:4269 but task is already holding lock: ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3851 [inline] ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x12c7/0x3d50 net/core/dev.c:4269 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); *** DEADLOCK *** May be due to missing lock nesting notation 12 locks held by kworker/u4:13/6537: #0: ffff888017e16938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900032f7d20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4ff850 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x166/0xd20 net/core/net_namespace.c:594 #3: ffffffff8e50bd28 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe5/0x9d0 net/core/dev.c:11446 #4: ffffffff8d2072e0 (console_lock){+.+.}-{0:0}, at: _printk+0xd1/0x111 kernel/printk/printk.c:2328 #5: ffffc90000007bc0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc2/0x6b0 kernel/time/timer.c:1501 #6: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #6: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #6: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: ip6_nd_hdr net/ipv6/ndisc.c:454 [inline] #6: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: ndisc_send_skb+0x5a8/0x14e0 net/ipv6/ndisc.c:505 #7: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #7: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #7: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x698/0x15f0 net/ipv6/ip6_output.c:123 #8: ffffffff8d32b120 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8d32b120 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #8: ffffffff8d32b120 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2d6/0x3d50 net/core/dev.c:4226 #9: ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #9: ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #9: ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3851 [inline] #9: ffff888058669258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x12c7/0x3d50 net/core/dev.c:4269 #10: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #10: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #10: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x402/0x1330 net/ipv4/ip_output.c:221 #11: ffffffff8d32b120 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #11: ffffffff8d32b120 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #11: ffffffff8d32b120 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2d6/0x3d50 net/core/dev.c:4226 stack backtrace: CPU: 0 PID: 6537 Comm: kworker/u4:13 Not tainted 6.1.127-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2983 [inline] check_deadlock kernel/locking/lockdep.c:3026 [inline] validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:3894 [inline] __dev_queue_xmit+0x22db/0x3d50 net/core/dev.c:4269 dev_queue_xmit include/linux/netdevice.h:3043 [inline] neigh_hh_output include/net/neighbour.h:528 [inline] neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xcfc/0x1330 net/ipv4/ip_output.c:228 iptunnel_xmit+0x513/0x920 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1f87/0x2690 net/ipv4/ip_tunnel.c:858 __gre_xmit net/ipv4/ip_gre.c:474 [inline] gre_tap_xmit+0x4eb/0x6e0 net/ipv4/ip_gre.c:751 __netdev_start_xmit include/linux/netdevice.h:4888 [inline] netdev_start_xmit include/linux/netdevice.h:4902 [inline] xmit_one net/core/dev.c:3627 [inline] dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3643 sch_direct_xmit+0x2b2/0x5e0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3864 [inline] __dev_queue_xmit+0x1a7a/0x3d50 net/core/dev.c:4269 dev_queue_xmit include/linux/netdevice.h:3043 [inline] neigh_hh_output include/net/neighbour.h:528 [inline] neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0xeae/0x15f0 net/ipv6/ip6_output.c:138 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline] ip6_finish_output+0x6a0/0xa80 net/ipv6/ip6_output.c:216 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbab/0x14e0 net/ipv6/ndisc.c:511 addrconf_rs_timer+0x357/0x610 net/ipv6/addrconf.c:3982 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1820 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571 __do_softirq kernel/softirq.c:605 [inline] invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:654 irq_exit_rcu+0x5/0x20 kernel/softirq.c:666 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:console_emit_next_record+0xd67/0x1000 kernel/printk/printk.c:2786 Code: f8 1b 00 44 0f b6 74 24 1f 48 83 7c 24 30 00 75 07 e8 1d f8 1b 00 eb 06 e8 16 f8 1b 00 fb 48 c7 84 24 a0 00 00 00 0e 36 e0 45 <43> c7 04 2c 00 00 00 00 4b c7 44 2c 0a 00 00 00 00 4b c7 44 2c 12 RSP: 0018:ffffc900032f7360 EFLAGS: 00000293 RAX: ffffffff816ea48a RBX: ffffffff816ea1cc RCX: ffff888073978000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900032f7610 R08: ffffffff816ea462 R09: fffffbfff224a04d R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 1ffff9200065ee80 R14: 0000000000000001 R15: 0000000000000000 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303 _printk+0xd1/0x111 kernel/printk/printk.c:2328 __dev_set_promiscuity+0x1df/0x5d0 net/core/dev.c:8387 dev_set_promiscuity+0x4d/0xd0 net/core/dev.c:8426 hsr_del_port+0x196/0x1f0 net/hsr/hsr_slave.c:216 hsr_del_ports+0x2d/0x90 net/hsr/hsr_device.c:393 hsr_dellink+0x3f/0x70 net/hsr/hsr_netlink.c:113 default_device_exit_batch+0x8b7/0x9d0 net/core/dev.c:11455 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x886/0xd20 net/core/net_namespace.c:640 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: f8 clc 1: 1b 00 sbb (%rax),%eax 3: 44 0f b6 74 24 1f movzbl 0x1f(%rsp),%r14d 9: 48 83 7c 24 30 00 cmpq $0x0,0x30(%rsp) f: 75 07 jne 0x18 11: e8 1d f8 1b 00 call 0x1bf833 16: eb 06 jmp 0x1e 18: e8 16 f8 1b 00 call 0x1bf833 1d: fb sti 1e: 48 c7 84 24 a0 00 00 movq $0x45e0360e,0xa0(%rsp) 25: 00 0e 36 e0 45 * 2a: 43 c7 04 2c 00 00 00 movl $0x0,(%r12,%r13,1) <-- trapping instruction 31: 00 32: 4b c7 44 2c 0a 00 00 movq $0x0,0xa(%r12,%r13,1) 39: 00 00 3b: 4b rex.WXB 3c: c7 .byte 0xc7 3d: 44 2c 12 rex.R sub $0x12,%al