============================================ WARNING: possible recursive locking detected 6.13.0-rc1-syzkaller-00371-g65fb414c93f4 #0 Not tainted -------------------------------------------- kworker/u8:26/7331 is trying to acquire lock: ffff8880610b4f30 (&hsr->seqnr_lock ){+.-.}-{3:3} , at: spin_lock_bh include/linux/spinlock.h:356 [inline] , at: hsr_dev_xmit+0x18a/0x210 net/hsr/hsr_device.c:234 but task is already holding lock: ffff88802453af30 (&hsr->seqnr_lock ){+.-.}-{3:3} , at: spin_lock_bh include/linux/spinlock.h:356 [inline] , at: hsr_dev_xmit+0x18a/0x210 net/hsr/hsr_device.c:234 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 kworker/u8:26/7331: #0: ffff88801baf5948 ((wq_completion)netns ){+.+.}-{0:0} , at: process_one_work kernel/workqueue.c:3204 [inline] , at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc90002fb7d00 (net_cleanup_work ){+.+.}-{0:0} , at: process_one_work kernel/workqueue.c:3205 [inline] , at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffffffff8e93ce80 (rcu_state.barrier_mutex ){+.+.}-{4:4} , at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4565 #3: ffffc90000007be0 ((&ndev->rs_timer) ){+.-.}-{0:0} , at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1790 #4: ffffffff8e937aa0 (rcu_read_lock ){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] , at: rcu_read_lock include/linux/rcupdate.h:849 [inline] , at: ip6_nd_hdr net/ipv6/ndisc.c:454 [inline] , at: ndisc_send_skb+0x563/0x1450 net/ipv6/ndisc.c:505 #5: ffffffff8e937aa0 (rcu_read_lock ){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] , at: rcu_read_lock include/linux/rcupdate.h:849 [inline] , at: ip6_finish_output2+0x63a/0x17b0 net/ipv6/ip6_output.c:126 #6: ffffffff8e937b00 (rcu_read_lock_bh ){....}-{1:3} , at: local_bh_disable include/linux/bottom_half.h:20 [inline] , at: rcu_read_lock_bh include/linux/rcupdate.h:901 [inline] , at: __dev_queue_xmit+0x2f4/0x3f50 net/core/dev.c:4359 #7: ffff88802453af30 (&hsr->seqnr_lock ){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ){+.-.}-{3:3}, at: hsr_dev_xmit+0x18a/0x210 net/hsr/hsr_device.c:234 #8: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #8: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #8: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xb6/0x2b50 net/hsr/hsr_forward.c:725 #9: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:901 [inline] #9: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2f4/0x3f50 net/core/dev.c:4359 #10: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #10: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #10: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x21d/0x1b40 net/bridge/br_device.c:50 #11: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #11: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:901 [inline] #11: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2f4/0x3f50 net/core/dev.c:4359 stack backtrace: CPU: 0 UID: 0 PID: 7331 Comm: kworker/u8:26 Not tainted 6.13.0-rc1-syzkaller-00371-g65fb414c93f4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] hsr_dev_xmit+0x18a/0x210 net/hsr/hsr_device.c:234 __netdev_start_xmit include/linux/netdevice.h:5045 [inline] netdev_start_xmit include/linux/netdevice.h:5054 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606 __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434 dev_queue_xmit include/linux/netdevice.h:3208 [inline] br_dev_queue_push_xmit+0x726/0x900 net/bridge/br_forward.c:53 NF_HOOK+0x3a7/0x460 include/linux/netfilter.h:314 br_forward_finish+0xd8/0x130 net/bridge/br_forward.c:66 NF_HOOK+0x3a7/0x460 include/linux/netfilter.h:314 __br_forward+0x489/0x660 net/bridge/br_forward.c:115 br_dev_xmit+0x1202/0x1b40 __netdev_start_xmit include/linux/netdevice.h:5045 [inline] netdev_start_xmit include/linux/netdevice.h:5054 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606 __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434 dev_queue_xmit include/linux/netdevice.h:3208 [inline] hsr_xmit net/hsr/hsr_forward.c:430 [inline] hsr_forward_do net/hsr/hsr_forward.c:571 [inline] hsr_forward_skb+0x179d/0x2b50 net/hsr/hsr_forward.c:730 hsr_dev_xmit+0x195/0x210 net/hsr/hsr_device.c:235 __netdev_start_xmit include/linux/netdevice.h:5045 [inline] netdev_start_xmit include/linux/netdevice.h:5054 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606 __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 NF_HOOK include/linux/netfilter.h:314 [inline] ndisc_send_skb+0xb30/0x1450 net/ipv6/ndisc.c:511 addrconf_rs_timer+0x371/0x670 net/ipv6/addrconf.c:4061 call_timer_fn+0x187/0x650 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [inline] __run_timers kernel/time/timer.c:2418 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430 run_timer_base kernel/time/timer.c:2439 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:655 irq_exit_rcu+0x9/0x30 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_single+0x45f/0x1990 kernel/smp.c:679 Code: 27 27 0c 00 41 83 e4 01 75 16 e8 dc 22 0c 00 4d 89 fc 44 8b 7c 24 24 eb 46 e8 cd 22 0c 00 eb 3f 4d 89 fc 44 8b 7c 24 24 f3 90 <42> 0f b6 04 2b 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 aa 22 0c RSP: 0018:ffffc90002fb78a0 EFLAGS: 00000293 RAX: ffffffff81934f76 RBX: 1ffff920005f6f31 RCX: ffff888032d49e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002fb7a38 R08: ffffffff81934f39 R09: 1ffff920005f6ee0 R10: dffffc0000000000 R11: fffff520005f6ee1 R12: 1ffff920005f6f2c R13: dffffc0000000000 R14: ffffc90002fb7988 R15: 0000000000000000 rcu_barrier+0x327/0x530 kernel/rcu/tree.c:4617 cleanup_net+0x958/0xcc0 net/core/net_namespace.c:643 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 0c 00 or $0x0,%al 2: 41 83 e4 01 and $0x1,%r12d 6: 75 16 jne 0x1e 8: e8 dc 22 0c 00 call 0xc22e9 d: 4d 89 fc mov %r15,%r12 10: 44 8b 7c 24 24 mov 0x24(%rsp),%r15d 15: eb 46 jmp 0x5d 17: e8 cd 22 0c 00 call 0xc22e9 1c: eb 3f jmp 0x5d 1e: 4d 89 fc mov %r15,%r12 21: 44 8b 7c 24 24 mov 0x24(%rsp),%r15d 26: f3 90 pause * 28: 42 0f b6 04 2b movzbl (%rbx,%r13,1),%eax <-- trapping instruction 2d: 84 c0 test %al,%al 2f: 75 10 jne 0x41 31: 41 f7 06 01 00 00 00 testl $0x1,(%r14) 38: 74 1e je 0x58 3a: e8 .byte 0xe8 3b: aa stos %al,%es:(%rdi) 3c: 22 .byte 0x22 3d: 0c .byte 0xc