=============================
WARNING: suspicious RCU usage
6.9.0-syzkaller-12071-g66ad4829ddd0 #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 syz-fuzzer/5888:
#0: ffffc90000a18c00 ((&p->forward_delay_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1789
#1: ffff888062ec0cb8 (&br->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#1: ffff888062ec0cb8 (&br->lock){+.-.}-{2:2}, at: br_forward_delay_timer_expired+0x50/0x440 net/bridge/br_stp_timer.c:86
#2: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#2: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
#2: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: br_mst_set_state+0x171/0x7a0 net/bridge/br_mst.c:105
stack backtrace:
CPU: 1 PID: 5888 Comm: syz-fuzzer Not tainted 6.9.0-syzkaller-12071-g66ad4829ddd0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
__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+0x29e/0x7a0 net/bridge/br_mst.c:106
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:1792
expire_timers kernel/time/timer.c:1843 [inline]
__run_timers kernel/time/timer.c:2417 [inline]
__run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2428
run_timer_base kernel/time/timer.c:2437 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2447
handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
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
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 0e 0f 6b f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 a3 d7 d4 f5 65 8b 05 34 22 73 74 85 c0 74 43 48 c7 04 24 0e 36
RSP: 0018:ffffc90013a979c0 EFLAGS: 00000206
RAX: b80511df6cc6ce00 RBX: 1ffff92002752f3c RCX: ffffffff9479d603
RDX: dffffc0000000000 RSI: ffffffff8bcab880 RDI: 0000000000000001
RBP: ffffc90013a97a50 R08: ffffffff8fad34ef R09: 1ffffffff1f5a69d
R10: dffffc0000000000 R11: fffffbfff1f5a69e R12: dffffc0000000000
R13: 1ffff92002752f38 R14: ffffc90013a979e0 R15: 0000000000000246
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__wake_up_common_lock+0x18c/0x1e0 kernel/sched/wait.c:108
pipe_write+0x128d/0x1a40 fs/pipe.c:602
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xa72/0xc90 fs/read_write.c:590
ksys_write+0x1a0/0x2c0 fs/read_write.c:643
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x472eb5
Code: 48 3d 01 f0 ff ff 76 05 b8 ff ff ff ff 89 44 24 10 c3 cc cc cc 48 8b 7c 24 08 48 8b 74 24 10 8b 54 24 18 b8 01 00 00 00 0f 05 <89> 44 24 20 c3 cc cc cc cc cc cc 8b 7c 24 08 48 8b 74 24 10 8b 54
RSP: 002b:000000c00139bdc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000c00139be1b RCX: 0000000000472eb5
RDX: 0000000000000001 RSI: 000000c00139be1b RDI: 0000000000000006
RBP: 000000c00139bdf0 R08: 0000003e7d9e90a1 R09: 0000003e7d9e90a1
R10: 000000409500d79b R11: 0000000000000246 R12: 000000c000040000
R13: 0000000000000004 R14: 000000c0008791e0 R15: 0000000000000000
bridge0: port 1(bridge_slave_0) entered learning state
bridge0: port 2(bridge_slave_1) entered learning state
bridge0: port 3(macvlan1) entered learning state
----------------
Code disassembly (best guess):
0: 9c pushf
1: 8f 44 24 20 pop 0x20(%rsp)
5: 42 80 3c 23 00 cmpb $0x0,(%rbx,%r12,1)
a: 74 08 je 0x14
c: 4c 89 f7 mov %r14,%rdi
f: e8 0e 0f 6b f6 call 0xf66b0f22
14: f6 44 24 21 02 testb $0x2,0x21(%rsp)
19: 75 52 jne 0x6d
1b: 41 f7 c7 00 02 00 00 test $0x200,%r15d
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 a3 d7 d4 f5 call 0xf5d4d7d2 <-- trapping instruction
2f: 65 8b 05 34 22 73 74 mov %gs:0x74732234(%rip),%eax # 0x7473226a
36: 85 c0 test %eax,%eax
38: 74 43 je 0x7d
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss