=============================
WARNING: suspicious RCU usage
6.9.0-rc6-syzkaller-00133-g19e35f24750d #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
3 locks held by modprobe/27500:
 #0: ffff88807a4827a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:108 [inline]
 #0: ffff88807a4827a0 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x314/0xd60 mm/mmap.c:3275
 #1: ffffc90000a08c00 ((&p->forward_delay_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1790
 #2: ffff88805f0eccb8 (&br->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #2: ffff88805f0eccb8 (&br->lock){+.-.}-{2:2}, at: br_forward_delay_timer_expired+0x50/0x440 net/bridge/br_stp_timer.c:86

stack backtrace:
CPU: 1 PID: 27500 Comm: modprobe Not tainted 6.9.0-rc6-syzkaller-00133-g19e35f24750d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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:check_kcov_mode kernel/kcov.c:173 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:236 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0xa4/0x120 kernel/kcov.c:341
Code: 8b 00 00 00 4c 8b 4c 24 20 65 4c 8b 1c 25 c0 d3 03 00 31 d2 eb 08 48 ff c2 49 39 d2 74 71 4c 8b 74 d6 10 65 8b 05 e4 bc 6d 7e <a9> 00 01 ff 00 74 11 a9 00 01 00 00 74 de 41 83 bb 14 16 00 00 00
RSP: 0018:ffffc90002f1f480 EFLAGS: 00000202
RAX: 0000000080000001 RBX: 0000000000000000 RCX: ffff88805e999e00
RDX: 0000000000000007 RSI: ffffffff8e1a2fa0 RDI: 0000000000000005
RBP: 0000000000000005 R08: 0000000000000005 R09: ffffffff8141572e
R10: 0000000000000008 R11: ffff88805e999e00 R12: ffffffff8fb9d0ec
R13: dffffc0000000000 R14: 0000000000000009 R15: 1ffff920005e3eb0
 unwind_next_frame+0x7be/0x2a00 arch/x86/kernel/unwind_orc.c:515
 arch_stack_walk+0x151/0x1b0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
 task_work_add+0x8b/0x3a0 kernel/task_work.c:48
 fput+0x11c/0x210 fs/file_table.c:482
 remove_vma mm/mmap.c:143 [inline]
 exit_mmap+0x666/0xd60 mm/mmap.c:3291
 __mmput+0x115/0x3c0 kernel/fork.c:1346
 exit_mm+0x220/0x310 kernel/exit.c:569
 do_exit+0x99e/0x27e0 kernel/exit.c:865
 do_group_exit+0x207/0x2c0 kernel/exit.c:1027
 __do_sys_exit_group kernel/exit.c:1038 [inline]
 __se_sys_exit_group kernel/exit.c:1036 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f90ea161a90
Code: Unable to access opcode bytes at 0x7f90ea161a66.
RSP: 002b:00007ffc896e9568 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f90ea252860 RCX: 00007f90ea161a90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000001
RBP: 00007f90ea252860 R08: 00007ffc896e93e0 R09: 00007ffc896e94c0
R10: 00007ffc896e9420 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f90ea256658 R15: 0000000000000001
 </TASK>
bridge0: port 3(geneve1) entered learning state
----------------
Code disassembly (best guess):
   0:	8b 00                	mov    (%rax),%eax
   2:	00 00                	add    %al,(%rax)
   4:	4c 8b 4c 24 20       	mov    0x20(%rsp),%r9
   9:	65 4c 8b 1c 25 c0 d3 	mov    %gs:0x3d3c0,%r11
  10:	03 00
  12:	31 d2                	xor    %edx,%edx
  14:	eb 08                	jmp    0x1e
  16:	48 ff c2             	inc    %rdx
  19:	49 39 d2             	cmp    %rdx,%r10
  1c:	74 71                	je     0x8f
  1e:	4c 8b 74 d6 10       	mov    0x10(%rsi,%rdx,8),%r14
  23:	65 8b 05 e4 bc 6d 7e 	mov    %gs:0x7e6dbce4(%rip),%eax        # 0x7e6dbd0e
* 2a:	a9 00 01 ff 00       	test   $0xff0100,%eax <-- trapping instruction
  2f:	74 11                	je     0x42
  31:	a9 00 01 00 00       	test   $0x100,%eax
  36:	74 de                	je     0x16
  38:	41 83 bb 14 16 00 00 	cmpl   $0x0,0x1614(%r11)
  3f:	00