=============================
WARNING: suspicious RCU usage
6.9.0-rc6-syzkaller-00053-g0106679839f7 #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
6 locks held by syz-executor.0/11715:
#0: ffff8880261f77c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xeb/0x180 fs/file.c:1191
#1: ffff8880244f0420 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x12f/0x260 fs/read_write.c:643
#2: ffff888034470e00 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
#2: ffff888034470e00 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: ext4_buffered_write_iter+0xb0/0x3d0 fs/ext4/file.c:294
#3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
#3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: folio_memcg_lock+0x29/0x640 mm/memcontrol.c:2195
#4: ffffc90000848cb0 ((&p->forward_delay_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11a/0x610 kernel/time/timer.c:1790
#5: ffff888046b68cb8 (&br->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#5: ffff888046b68cb8 (&br->lock){+.-.}-{2:2}, at: br_forward_delay_timer_expired+0x4f/0x560 net/bridge/br_stp_timer.c:86
stack backtrace:
CPU: 2 PID: 11715 Comm: syz-executor.0 Not tainted 6.9.0-rc6-syzkaller-00053-g0106679839f7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:114
lockdep_rcu_suspicious+0x20b/0x3b0 kernel/locking/lockdep.c:6712
nbp_vlan_group net/bridge/br_private.h:1599 [inline]
br_mst_set_state+0x4cd/0x5e0 net/bridge/br_mst.c:105
br_set_state+0x542/0x880 net/bridge/br_stp.c:47
br_forward_delay_timer_expired+0x311/0x560 net/bridge/br_stp_timer.c:88
call_timer_fn+0x1a0/0x610 kernel/time/timer.c:1793
expire_timers kernel/time/timer.c:1844 [inline]
__run_timers+0x74b/0xaf0 kernel/time/timer.c:2418
__run_timer_base kernel/time/timer.c:2429 [inline]
__run_timer_base kernel/time/timer.c:2422 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2438
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2448
__do_softirq+0x218/0x922 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:633 [inline]
irq_exit_rcu+0xb9/0x120 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 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+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 66 c1 8c f6 48 89 df e8 be 3d 8d f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 78 7e f6 65 8b 05 66 b8 24 75 85 c0 74 16 5b
RSP: 0018:ffffc900032af968 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff888034470ee0 RCX: 1ffffffff27c38ed
RDX: 0000000000000000 RSI: ffffffff8b0cae00 RDI: ffffffff8b6f55a0
RBP: 0000000000000246 R08: 0000000000000001 R09: fffffbfff27bb644
R10: ffffffff93ddb227 R11: 0000000000000001 R12: 000000000003d78c
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880617a1570
mark_buffer_dirty+0x368/0x440 fs/buffer.c:1200
__block_commit_write+0x108/0x270 fs/buffer.c:2177
block_write_end+0xc8/0x250 fs/buffer.c:2253
ext4_da_do_write_end fs/ext4/inode.c:2955 [inline]
ext4_da_write_end+0x1e0/0xd50 fs/ext4/inode.c:3028
generic_perform_write+0x337/0x620 mm/filemap.c:3985
ext4_buffered_write_iter+0x11f/0x3d0 fs/ext4/file.c:299
ext4_file_write_iter+0x874/0x1a40 fs/ext4/file.c:698
call_write_iter include/linux/fs.h:2110 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x6db/0x1100 fs/read_write.c:590
ksys_write+0x12f/0x260 fs/read_write.c:643
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a51a7dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a527d20c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4a51bac050 RCX: 00007f4a51a7dea9
RDX: 00000000fffffdf5 RSI: 0000000020000000 RDI: 0000000000000007
RBP: 00007f4a51aca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f4a51bac050 R15: 00007ffd2715df88
bridge0: port 2(bridge_slave_1) entered learning state
----------------
Code disassembly (best guess):
0: f5 cmc
1: 53 push %rbx
2: 48 8b 74 24 10 mov 0x10(%rsp),%rsi
7: 48 89 fb mov %rdi,%rbx
a: 48 83 c7 18 add $0x18,%rdi
e: e8 66 c1 8c f6 call 0xf68cc179
13: 48 89 df mov %rbx,%rdi
16: e8 be 3d 8d f6 call 0xf68d3dd9
1b: f7 c5 00 02 00 00 test $0x200,%ebp
21: 75 23 jne 0x46
23: 9c pushf
24: 58 pop %rax
25: f6 c4 02 test $0x2,%ah
28: 75 37 jne 0x61
* 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction
2f: e8 a5 78 7e f6 call 0xf67e78d9
34: 65 8b 05 66 b8 24 75 mov %gs:0x7524b866(%rip),%eax # 0x7524b8a1
3b: 85 c0 test %eax,%eax
3d: 74 16 je 0x55
3f: 5b pop %rbx