=============================
WARNING: suspicious RCU usage
6.9.0-rc6-syzkaller-00139-g9a169c267e94 #0 Not tainted
-----------------------------
net/bridge/br_private.h:1599 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
5 locks held by kworker/u8:15/6910:
 #0: ffff888015ecd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3242 [inline]
 #0: ffff888015ecd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3348
 #1: ffffc9000a497d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3243 [inline]
 #1: ffffc9000a497d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3348
 #2: ffffffff8f59a350 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:594
 #3: ffffc90000007c00 ((&p->forward_delay_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1790
 #4: ffff888062e5ccb8 (&br->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #4: ffff888062e5ccb8 (&br->lock){+.-.}-{2:2}, at: br_forward_delay_timer_expired+0x50/0x440 net/bridge/br_stp_timer.c:86

stack backtrace:
CPU: 0 PID: 6910 Comm: kworker/u8:15 Not tainted 6.9.0-rc6-syzkaller-00139-g9a169c267e94 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: netns cleanup_net
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
 nbp_vlan_group net/bridge/br_private.h:1599 [inline]
 br_mst_set_state+0x1ea/0x650 net/bridge/br_mst.c:105
 br_set_state+0x28a/0x7b0 net/bridge/br_stp.c:47
 br_forward_delay_timer_expired+0x176/0x440 net/bridge/br_stp_timer.c:88
 call_timer_fn+0x18e/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:2429
 run_timer_base kernel/time/timer.c:2438 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2448
 __do_softirq+0x2c6/0x980 kernel/softirq.c:554
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_is_held_type+0x13b/0x190
Code: 75 44 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 42 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc9000a497818 EFLAGS: 00000206
RAX: f6f8712996697000 RBX: 0000000000000000 RCX: ffff88802c95da00
RDX: 0000000000000000 RSI: ffffffff8bcaca20 RDI: ffffffff8c1f7ee0
RBP: 0000000000000003 R08: ffffffff8fa8faaf R09: 1ffffffff1f51f55
R10: dffffc0000000000 R11: fffffbfff1f51f56 R12: 0000000000000246
R13: ffff88802c95da00 R14: 00000000ffffffff R15: ffffffff8e334d20
 lock_is_held include/linux/lockdep.h:231 [inline]
 __might_resched+0xf4/0x780 kernel/sched/core.c:10159
 inet_twsk_purge+0x122/0xa50 net/ipv4/inet_timewait_sock.c:276
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x89d/0xcc0 net/core/net_namespace.c:640
 process_one_work kernel/workqueue.c:3267 [inline]
 process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3348
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3429
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
bridge0: port 1(bridge_slave_0) entered learning state
bridge0: port 2(bridge_slave_1) entered learning state
bridge0: port 3(team0) entered learning state
bridge0: port 4(geneve1) entered learning state
----------------
Code disassembly (best guess):
   0:	75 44                	jne    0x46
   2:	48 c7 04 24 00 00 00 	movq   $0x0,(%rsp)
   9:	00
   a:	9c                   	pushf
   b:	8f 04 24             	pop    (%rsp)
   e:	f7 04 24 00 02 00 00 	testl  $0x200,(%rsp)
  15:	75 4c                	jne    0x63
  17:	41 f7 c4 00 02 00 00 	test   $0x200,%r12d
  1e:	74 01                	je     0x21
  20:	fb                   	sti
  21:	65 48 8b 04 25 28 00 	mov    %gs:0x28,%rax
  28:	00 00
* 2a:	48 3b 44 24 08       	cmp    0x8(%rsp),%rax <-- trapping instruction
  2f:	75 42                	jne    0x73
  31:	89 d8                	mov    %ebx,%eax
  33:	48 83 c4 10          	add    $0x10,%rsp
  37:	5b                   	pop    %rbx
  38:	41 5c                	pop    %r12
  3a:	41 5d                	pop    %r13
  3c:	41 5e                	pop    %r14
  3e:	41 5f                	pop    %r15