lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ dhcpcd-run-hook/23530 is trying to acquire lock: ffff88802b9d7158 (_xmit_X25#2){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:347 [inline] ffff88802b9d7158 (_xmit_X25#2){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4838 [inline] ffff88802b9d7158 (_xmit_X25#2){+.-.}-{3:3}, at: __dev_queue_xmit+0xe9c/0x3820 net/core/dev.c:4920 but task is already holding lock: ffff88805a0345c0 (&lapb->lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:353 [inline] ffff88805a0345c0 (&lapb->lock){+.-.}-{3:3}, at: lapb_t1timer_expiry+0x33/0xaa0 net/lapb/lapb_timer.c:99 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&lapb->lock){+.-.}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:182 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:205 spin_lock_bh include/linux/spinlock.h:353 [inline] lapb_data_received+0xfc/0x1c0 net/lapb/lapb_iface.c:398 lapbeth_rcv+0x34d/0x640 drivers/net/wan/lapbether.c:142 __netif_receive_skb_one_core net/core/dev.c:6264 [inline] __netif_receive_skb net/core/dev.c:6377 [inline] process_backlog+0xc26/0x18b0 net/core/dev.c:6728 __napi_poll+0xaa/0x330 net/core/dev.c:7787 napi_poll net/core/dev.c:7850 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8007 handle_softirqs+0x226/0x860 kernel/softirq.c:645 do_softirq+0x77/0xd0 kernel/softirq.c:546 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 spin_unlock_bh include/linux/spinlock.h:407 [inline] lapb_device_event+0x4f3/0x680 net/lapb/lapb_iface.c:527 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline] call_netdevice_notifiers net/core/dev.c:2327 [inline] __dev_notify_flags+0x31e/0x510 net/core/dev.c:9853 netif_change_flags+0xde/0x1b0 net/core/dev.c:9882 dev_change_flags+0x128/0x260 net/core/dev_api.c:68 devinet_ioctl+0x966/0x1c50 net/ipv4/devinet.c:1199 inet_ioctl+0x42a/0x560 net/ipv4/af_inet.c:1010 sock_do_ioctl+0x101/0x320 net/socket.c:1325 sock_ioctl+0x57a/0x7e0 net/socket.c:1446 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&lapbeth->up_lock){+.-.}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:182 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:205 spin_lock_bh include/linux/spinlock.h:353 [inline] lapbeth_xmit+0x32/0x260 drivers/net/wan/lapbether.c:191 __netdev_start_xmit include/linux/netdevice.h:5429 [inline] netdev_start_xmit include/linux/netdevice.h:5438 [inline] xmit_one net/core/dev.c:3937 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3953 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4926 dev_queue_xmit include/linux/netdevice.h:3461 [inline] tx+0x6b/0x190 drivers/block/aoe/aoenet.c:62 kthread+0x1ed/0x420 drivers/block/aoe/aoecmd.c:1241 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (_xmit_X25#2){+.-.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173 spin_lock include/linux/spinlock.h:347 [inline] __netif_tx_lock include/linux/netdevice.h:4838 [inline] __dev_queue_xmit+0xe9c/0x3820 net/core/dev.c:4920 neigh_output include/net/neighbour.h:560 [inline] ip_finish_output2+0xc4b/0x10b0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:314 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:437 iptunnel_xmit+0x626/0xd10 net/ipv4/ip_tunnel_core.c:97 udp_tunnel_xmit_skb+0x29b/0x3e0 net/ipv4/udp_tunnel_core.c:187 vxlan_xmit_one+0x21f6/0x2eb0 drivers/net/vxlan/vxlan_core.c:2569 vxlan_xmit+0x1e19/0x33b0 drivers/net/vxlan/vxlan_core.c:2858 __netdev_start_xmit include/linux/netdevice.h:5429 [inline] netdev_start_xmit include/linux/netdevice.h:5438 [inline] xmit_one net/core/dev.c:3937 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3953 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4926 lapb_data_transmit+0x90/0xb0 net/lapb/lapb_iface.c:447 lapb_transmit_buffer+0x163/0x200 net/lapb/lapb_out.c:149 lapb_t1timer_expiry+0x68d/0xaa0 net/lapb/lapb_timer.c:-1 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2374 [inline] __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386 run_timer_base kernel/time/timer.c:2395 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 lock_is_held_type+0x45/0x150 kernel/locking/lockdep.c:6009 lock_is_held include/linux/lockdep.h:249 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:676 [inline] mas_slot lib/maple_tree.c:709 [inline] mas_get_slot lib/maple_tree.c:6568 [inline] mas_validate_gaps lib/maple_tree.c:-1 [inline] mt_validate+0x25e7/0x4260 lib/maple_tree.c:7112 validate_mm+0xd4/0x4f0 mm/vma.c:696 __split_vma+0x918/0xa60 mm/vma.c:614 vms_gather_munmap_vmas+0x4e3/0x1370 mm/vma.c:1528 __mmap_setup mm/vma.c:2546 [inline] __mmap_region mm/vma.c:2869 [inline] mmap_region+0x928/0x2270 mm/vma.c:2974 do_mmap+0xe0a/0x1300 mm/mmap.c:573 vm_mmap_pgoff+0x272/0x4e0 mm/util.c:581 ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:619 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: _xmit_X25#2 --> &lapbeth->up_lock --> &lapb->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&lapb->lock); lock(&lapbeth->up_lock); lock(&lapb->lock); lock(_xmit_X25#2); *** DEADLOCK *** locks held by dhcpcd-run-hook/23530: 9, last CPU#0: #0: ffff8880398e36b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline] #0: ffff8880398e36b8 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1dd/0x4e0 mm/util.c:579 #1: ffffc90000007cc0 ((&lapb->t1timer)){+.-.}-{0:0}, at: call_timer_fn+0xd5/0x5f0 kernel/time/timer.c:1745 #2: ffff88805a0345c0 (&lapb->lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:353 [inline] #2: ffff88805a0345c0 (&lapb->lock){+.-.}-{3:3}, at: lapb_t1timer_expiry+0x33/0xaa0 net/lapb/lapb_timer.c:99 #3: ffffffff8ed5cb40 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8ed5cb40 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:902 [inline] #3: ffffffff8ed5cb40 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x3820 net/core/dev.c:4844 #4: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #4: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #4: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: vxlan_xmit+0x175d/0x33b0 drivers/net/vxlan/vxlan_core.c:2814 #5: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #5: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #5: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: vxlan_xmit_one+0x1407/0x2eb0 drivers/net/vxlan/vxlan_core.c:2487 #6: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #6: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #6: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5a/0x450 net/ipv4/ip_output.c:432 #7: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #7: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #7: ffffffff8ed5cae0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3de/0x10b0 net/ipv4/ip_output.c:229 #8: ffffffff8ed5cb40 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8ed5cb40 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:902 [inline] #8: ffffffff8ed5cb40 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x3820 net/core/dev.c:4844 stack backtrace: CPU: 0 UID: 0 PID: 23530 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173 spin_lock include/linux/spinlock.h:347 [inline] __netif_tx_lock include/linux/netdevice.h:4838 [inline] __dev_queue_xmit+0xe9c/0x3820 net/core/dev.c:4920 neigh_output include/net/neighbour.h:560 [inline] ip_finish_output2+0xc4b/0x10b0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:314 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:437 iptunnel_xmit+0x626/0xd10 net/ipv4/ip_tunnel_core.c:97 udp_tunnel_xmit_skb+0x29b/0x3e0 net/ipv4/udp_tunnel_core.c:187 vxlan_xmit_one+0x21f6/0x2eb0 drivers/net/vxlan/vxlan_core.c:2569 vxlan_xmit+0x1e19/0x33b0 drivers/net/vxlan/vxlan_core.c:2858 __netdev_start_xmit include/linux/netdevice.h:5429 [inline] netdev_start_xmit include/linux/netdevice.h:5438 [inline] xmit_one net/core/dev.c:3937 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3953 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4926 lapb_data_transmit+0x90/0xb0 net/lapb/lapb_iface.c:447 lapb_transmit_buffer+0x163/0x200 net/lapb/lapb_out.c:149 lapb_t1timer_expiry+0x68d/0xaa0 net/lapb/lapb_timer.c:-1 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2374 [inline] __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386 run_timer_base kernel/time/timer.c:2395 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_is_held_type+0x45/0x150 kernel/locking/lockdep.c:-1 Code: 84 e4 00 00 00 65 8b 05 71 bd ae 07 85 c0 0f 85 d5 00 00 00 65 4c 8b 2d b1 78 ae 07 41 83 bd a4 0b 00 00 00 0f 85 bf 00 00 00 <89> f5 49 89 fe 9c 41 5c fa 48 c7 c7 e0 3d 43 8e e8 e6 1b 00 00 65 RSP: 0018:ffffc900037eeee8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00000000ffffffff RCX: ffff888077e4ddc0 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff8880398e36b8 RBP: ffffc900037ef110 R08: ffff888077e4ddc0 R09: 0000000000000005 R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000001 R13: ffff888077e4ddc0 R14: 00007f052dc14fff R15: ffff8880398e36b8 lock_is_held include/linux/lockdep.h:249 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:676 [inline] mas_slot lib/maple_tree.c:709 [inline] mas_get_slot lib/maple_tree.c:6568 [inline] mas_validate_gaps lib/maple_tree.c:-1 [inline] mt_validate+0x25e7/0x4260 lib/maple_tree.c:7112 validate_mm+0xd4/0x4f0 mm/vma.c:696 __split_vma+0x918/0xa60 mm/vma.c:614 vms_gather_munmap_vmas+0x4e3/0x1370 mm/vma.c:1528 __mmap_setup mm/vma.c:2546 [inline] __mmap_region mm/vma.c:2869 [inline] mmap_region+0x928/0x2270 mm/vma.c:2974 do_mmap+0xe0a/0x1300 mm/mmap.c:573 vm_mmap_pgoff+0x272/0x4e0 mm/util.c:581 ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:619 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f052dcf3242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007ffdceec5db8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f052d9f8000 RCX: 00007f052dcf3242 RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007f052d9f8000 RBP: 0000000000000812 R08: 0000000000000003 R09: 000000000002c000 R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffdceec5e78 R13: 00007f052dcc8ab0 R14: 00007ffdceec6230 R15: 00000fffb9dd8bba lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 lapbether: lapb_data_request error - 4 ---------------- Code disassembly (best guess): 0: 84 e4 test %ah,%ah 2: 00 00 add %al,(%rax) 4: 00 65 8b add %ah,-0x75(%rbp) 7: 05 71 bd ae 07 add $0x7aebd71,%eax c: 85 c0 test %eax,%eax e: 0f 85 d5 00 00 00 jne 0xe9 14: 65 4c 8b 2d b1 78 ae mov %gs:0x7ae78b1(%rip),%r13 # 0x7ae78cd 1b: 07 1c: 41 83 bd a4 0b 00 00 cmpl $0x0,0xba4(%r13) 23: 00 24: 0f 85 bf 00 00 00 jne 0xe9 * 2a: 89 f5 mov %esi,%ebp <-- trapping instruction 2c: 49 89 fe mov %rdi,%r14 2f: 9c pushf 30: 41 5c pop %r12 32: fa cli 33: 48 c7 c7 e0 3d 43 8e mov $0xffffffff8e433de0,%rdi 3a: e8 e6 1b 00 00 call 0x1c25 3f: 65 gs