============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.0.2750/14830 is trying to acquire lock: ffff888035c35070 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] ffff888035c35070 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 but task is already holding lock: ffff888026681070 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] ffff888026681070 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x3cd/0xcf0 net/hsr/hsr_device.c:330 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&hsr->seqnr_lock); lock(&hsr->seqnr_lock); *** DEADLOCK *** May be due to missing lock nesting notation 12 locks held by syz.0.2750/14830: #0: ffffffff9057ca00 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff9057ca00 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff9057ca00 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:595 #1: ffffffff9002d000 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff9002d000 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline] #1: ffffffff9002d000 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30 net/core/rtnetlink.c:4194 #2: ffffc90000a08cc0 ((&hsr->announce_proxy_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x5e0 kernel/time/timer.c:1745 #3: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #3: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: hsr_proxy_announce+0x9c/0x430 net/hsr/hsr_device.c:466 #4: ffff888026681070 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] #4: ffff888026681070 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x3cd/0xcf0 net/hsr/hsr_device.c:330 #5: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #5: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #5: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xb9/0x2b70 net/hsr/hsr_forward.c:772 #6: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #6: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] #6: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x3820 net/core/dev.c:4799 #7: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #7: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #7: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: bond_start_xmit+0xb4/0x19e0 drivers/net/bonding/bond_main.c:5601 #8: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] #8: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x3820 net/core/dev.c:4799 #9: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #9: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #9: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x19d/0x1a30 net/bridge/br_device.c:52 #10: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #10: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] #10: ffffffff8eb59cc0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x3820 net/core/dev.c:4799 #11: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #11: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #11: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229 stack backtrace: CPU: 1 UID: 0 PID: 14830 Comm: syz.0.2750 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x24df/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:182 spin_lock_bh include/linux/spinlock.h:348 [inline] hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 __netdev_start_xmit include/linux/netdevice.h:5424 [inline] netdev_start_xmit include/linux/netdevice.h:5433 [inline] xmit_one net/core/dev.c:3892 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3908 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4881 dev_queue_xmit include/linux/netdevice.h:3451 [inline] br_dev_queue_push_xmit+0x370/0x4b0 net/bridge/br_forward.c:53 NF_HOOK+0x360/0x3f0 include/linux/netfilter.h:325 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66 NF_HOOK+0x360/0x3f0 include/linux/netfilter.h:325 __br_forward+0x397/0x540 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver net/bridge/br_forward.c:191 [inline] br_flood+0x3e6/0x8d0 net/bridge/br_forward.c:245 br_dev_xmit+0x1235/0x1a30 net/bridge/br_device.c:108 __netdev_start_xmit include/linux/netdevice.h:5424 [inline] netdev_start_xmit include/linux/netdevice.h:5433 [inline] xmit_one net/core/dev.c:3892 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3908 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4881 __bond_start_xmit drivers/net/bonding/bond_main.c:-1 [inline] bond_start_xmit+0xd4f/0x19e0 drivers/net/bonding/bond_main.c:5603 __netdev_start_xmit include/linux/netdevice.h:5424 [inline] netdev_start_xmit include/linux/netdevice.h:5433 [inline] xmit_one net/core/dev.c:3892 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3908 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4881 dev_queue_xmit include/linux/netdevice.h:3451 [inline] hsr_xmit net/hsr/hsr_forward.c:440 [inline] hsr_forward_do net/hsr/hsr_forward.c:603 [inline] hsr_forward_skb+0x1701/0x2b70 net/hsr/hsr_forward.c:777 send_hsr_supervision_frame+0x733/0xcf0 net/hsr/hsr_device.c:364 hsr_proxy_announce+0x20e/0x430 net/hsr/hsr_device.c:477 call_timer_fn+0x192/0x5e0 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+0x225/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:206 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ca 16 cf f5 48 89 df e8 22 8c cf f5 e8 1d 6e fb f5 fb bf 01 00 00 00 42 a2 c0 f5 65 8b 05 3b 02 99 07 85 c0 74 07 5b c3 cc cc cc cc RSP: 0018:ffffc9000442ec90 EFLAGS: 00000206 RAX: 000000000000017d RBX: ffffffff9aacabc0 RCX: 0000000080000001 RDX: 0000000000000006 RSI: ffffffff8e22e65b RDI: 0000000000000001 RBP: ffffc9000442ee60 R08: ffffffff90579037 R09: 1ffffffff20af206 R10: dffffc0000000000 R11: fffffbfff20af207 R12: dffffc0000000000 R13: 1ffff92000885d94 R14: ffff8880570d98f8 R15: 0000000000000000 spin_unlock_irq include/linux/spinlock.h:402 [inline] xa_store_irq include/linux/xarray.h:624 [inline] ref_tracker_dir_debugfs+0x264/0x360 lib/ref_tracker.c:446 ref_tracker_dir_init include/linux/ref_tracker.h:70 [inline] alloc_netdev_mqs+0x275/0x12b0 net/core/dev.c:12071 rtnl_create_link+0x321/0xd70 net/core/rtnetlink.c:3757 rtnl_newlink_create+0x258/0x7b0 net/core/rtnetlink.c:3939 __rtnl_newlink net/core/rtnetlink.c:4078 [inline] rtnl_newlink+0x166d/0x1c30 net/core/rtnetlink.c:4195 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7112 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3a3619df99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3a36fe5028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f3a36425fa0 RCX: 00007f3a3619df99 RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000000000000005 RBP: 00007f3a36234ec4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3a36426038 R14: 00007f3a36425fa0 R15: 00007ffc8ccdab38 IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available IPVS: rr: UDP 224.0.0.2:0 - no destination available ---------------- Code disassembly (best guess): 0: 90 nop 1: f3 0f 1e fa endbr64 5: 53 push %rbx 6: 48 89 fb mov %rdi,%rbx 9: 48 83 c7 18 add $0x18,%rdi d: 48 8b 74 24 08 mov 0x8(%rsp),%rsi 12: e8 ca 16 cf f5 call 0xf5cf16e1 17: 48 89 df mov %rbx,%rdi 1a: e8 22 8c cf f5 call 0xf5cf8c41 1f: e8 1d 6e fb f5 call 0xf5fb6e41 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 42 a2 c0 f5 call 0xf5c0a271 <-- trapping instruction 2f: 65 8b 05 3b 02 99 07 mov %gs:0x799023b(%rip),%eax # 0x7990271 36: 85 c0 test %eax,%eax 38: 74 07 je 0x41 3a: 5b pop %rbx 3b: c3 ret 3c: cc int3 3d: cc int3 3e: cc int3 3f: cc int3