============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.0.4830/24452 is trying to acquire lock: ffff888042ab50b0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:353 [inline] ffff888042ab50b0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 but task is already holding lock: ffff888042ab50b0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:353 [inline] ffff888042ab50b0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_prp_supervision_frame+0x1fb/0x8b0 net/hsr/hsr_device.c:401 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 locks held by syz.0.4830/24452: 11, last CPU#1: #0: ffffc90000a08ce0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd5/0x5f0 kernel/time/timer.c:1746 #1: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x89/0x370 net/hsr/hsr_device.c:446 #2: ffff888042ab50b0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:353 [inline] #2: ffff888042ab50b0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_prp_supervision_frame+0x1fb/0x8b0 net/hsr/hsr_device.c:401 #3: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #3: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #3: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xb9/0x2b70 net/hsr/hsr_forward.c:772 #4: ffffffff8ff5a380 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #4: ffffffff8ff5a380 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:902 [inline] #4: ffffffff8ff5a380 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x3920 net/core/dev.c:5002 #5: ffff88807b2b9228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:359 [inline] #5: ffff88807b2b9228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:206 [inline] #5: ffff88807b2b9228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4394 [inline] #5: ffff88807b2b9228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: __dev_queue_xmit+0x114e/0x3920 net/core/dev.c:5046 #6: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #6: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #6: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x11e/0x540 net/ipv6/ip6_output.c:236 #7: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #7: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #7: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x203/0x1650 net/ipv6/ndisc.c:483 #8: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #8: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #8: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x11e/0x540 net/ipv6/ip6_output.c:236 #9: ffffffff8ff5a380 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8ff5a380 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:902 [inline] #9: ffffffff8ff5a380 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x3920 net/core/dev.c:5002 #10: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #10: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #10: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229 stack backtrace: CPU: 1 UID: 0 PID: 24452 Comm: syz.0.4830 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_deadlock_bug+0x27a/0x290 kernel/locking/lockdep.c:3085 check_deadlock kernel/locking/lockdep.c:3137 [inline] validate_chain kernel/locking/lockdep.c:3939 [inline] __lock_acquire+0x25db/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __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] hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 __netdev_start_xmit include/linux/netdevice.h:5457 [inline] netdev_start_xmit include/linux/netdevice.h:5466 [inline] xmit_one net/core/dev.c:4068 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:4084 __dev_queue_xmit+0x14d1/0x3920 net/core/dev.c:5088 NF_HOOK_COND include/linux/netfilter.h:314 [inline] ip6_output+0x337/0x540 net/ipv6/ip6_output.c:248 dst_output include/net/dst.h:472 [inline] NF_HOOK include/linux/netfilter.h:325 [inline] ndisc_send_skb+0xcb2/0x1650 net/ipv6/ndisc.c:513 ndisc_send_ns net/ipv6/ndisc.c:672 [inline] ndisc_solicit+0x374/0x670 net/ipv6/ndisc.c:763 neigh_probe net/core/neighbour.c:1096 [inline] __neigh_event_send+0xf0c/0x1510 net/core/neighbour.c:1276 neigh_event_send_probe include/net/neighbour.h:474 [inline] neigh_event_send include/net/neighbour.h:480 [inline] neigh_resolve_output+0x1a1/0x720 net/core/neighbour.c:1618 NF_HOOK_COND include/linux/netfilter.h:314 [inline] ip6_output+0x337/0x540 net/ipv6/ip6_output.c:248 ip6tunnel_xmit+0x200/0x620 include/net/ip6_tunnel.h:175 ip6_tnl_xmit+0x2039/0x27f0 net/ipv6/ip6_tunnel.c:1285 __gre6_xmit+0xa68/0xd90 net/ipv6/ip6_gre.c:784 ip6gre_xmit_other net/ipv6/ip6_gre.c:875 [inline] ip6gre_tunnel_xmit+0xa52/0x1010 net/ipv6/ip6_gre.c:906 __netdev_start_xmit include/linux/netdevice.h:5457 [inline] netdev_start_xmit include/linux/netdevice.h:5466 [inline] xmit_one net/core/dev.c:4068 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:4084 sch_direct_xmit+0x257/0x4c0 net/sched/sch_generic.c:411 __dev_xmit_skb net/core/dev.c:4407 [inline] __dev_queue_xmit+0x179a/0x3920 net/core/dev.c:5046 dev_queue_xmit include/linux/netdevice.h:3485 [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_prp_supervision_frame+0x49a/0x8b0 net/hsr/hsr_device.c:432 hsr_announce+0x1db/0x370 net/hsr/hsr_device.c:448 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1749 expire_timers kernel/time/timer.c:1800 [inline] __run_timers kernel/time/timer.c:2375 [inline] __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2387 run_timer_base kernel/time/timer.c:2396 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2406 handle_softirqs+0x265/0x8d0 kernel/softirq.c:669 __do_softirq kernel/softirq.c:703 [inline] invoke_softirq kernel/softirq.c:542 [inline] __irq_exit_rcu+0xc6/0x220 kernel/softirq.c:786 irq_exit_rcu+0x9/0x30 kernel/softirq.c:809 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:reg_type_str+0x2c4/0x340 kernel/bpf/log.c:448 Code: 00 4c 8b 03 be 80 05 00 00 4c 89 f7 48 c7 c2 e0 64 36 8c 4c 89 e1 4c 8d 4c 24 60 e8 d6 72 13 0a 48 b8 f8 f8 f8 f8 f8 f8 f8 f8 <4b> 89 44 3d 08 66 43 c7 44 3d 04 f8 f8 48 c7 44 24 40 0e 36 e0 45 RSP: 0018:ffffc90003b07060 EFLAGS: 00000246 RAX: f8f8f8f8f8f8f8f8 RBX: ffffffff8c366010 RCX: 3043f1ed217d5900 RDX: ffffc9000ecd9000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90003b07190 R08: ffff888028da8000 R09: 0000000000000008 R10: 0000000000000007 R11: 0000000000000002 R12: ffffc90003b070e0 R13: 1ffff92000760e14 R14: ffff88803eff44a0 R15: dffffc0000000000 print_reg_state+0x13c/0x1b60 kernel/bpf/log.c:647 print_verifier_state+0x217/0x1c80 kernel/bpf/log.c:727 do_check kernel/bpf/verifier.c:20635 [inline] do_check_common+0x45d9/0x7590 kernel/bpf/verifier.c:21922 do_check_main+0x95/0x1f0 kernel/bpf/verifier.c:22024 bpf_check+0x302b/0x34e0 kernel/bpf/verifier.c:24036 bpf_prog_load+0x14da/0x1c60 kernel/bpf/syscall.c:3172 __sys_bpf+0xd86/0xe00 kernel/bpf/syscall.c:6460 __do_sys_bpf kernel/bpf/syscall.c:6582 [inline] __se_sys_bpf kernel/bpf/syscall.c:6579 [inline] __x64_sys_bpf+0xba/0xd0 kernel/bpf/syscall.c:6579 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: 0033:0x7fd04519fb19 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:00007fd046073028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fd045425fa0 RCX: 00007fd04519fb19 RDX: 0000000000000094 RSI: 0000200000000640 RDI: 0000000000000005 RBP: 00007fd045237b70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd045426038 R14: 00007fd045425fa0 R15: 00007ffee1e11578 ---------------- Code disassembly (best guess): 0: 00 4c 8b 03 add %cl,0x3(%rbx,%rcx,4) 4: be 80 05 00 00 mov $0x580,%esi 9: 4c 89 f7 mov %r14,%rdi c: 48 c7 c2 e0 64 36 8c mov $0xffffffff8c3664e0,%rdx 13: 4c 89 e1 mov %r12,%rcx 16: 4c 8d 4c 24 60 lea 0x60(%rsp),%r9 1b: e8 d6 72 13 0a call 0xa1372f6 20: 48 b8 f8 f8 f8 f8 f8 movabs $0xf8f8f8f8f8f8f8f8,%rax 27: f8 f8 f8 * 2a: 4b 89 44 3d 08 mov %rax,0x8(%r13,%r15,1) <-- trapping instruction 2f: 66 43 c7 44 3d 04 f8 movw $0xf8f8,0x4(%r13,%r15,1) 36: f8 37: 48 c7 44 24 40 0e 36 movq $0x45e0360e,0x40(%rsp) 3e: e0 45