rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=def4/1/0x4000000000000000 softirq=109125/109126 fqs=5247
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:     6680          0            0
rcu: 	cputime:      237          0        52262   ==> 52510(ms)
rcu: 	(t=10502 jiffies g=74717 q=3290 ncpus=2)
CPU: 1 UID: 0 PID: 22488 Comm: syz.0.4673 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:qdisc_tree_reduce_backlog+0x1f6/0x480
Code: 89 f8 48 c1 e8 03 49 89 ee 80 3c 28 00 74 08 4c 89 ff e8 6d bf 9e f8 49 8b 2f 48 83 c5 08 48 89 e8 48 c1 e8 03 42 80 3c 30 00 <74> 08 48 89 ef e8 50 bf 9e f8 4d 89 ef 85 db 74 0d e8 f4 55 3b f8
RSP: 0018:ffffc900062def48 EFLAGS: 00000246
RAX: 1ffffffff1f48162 RBX: 0000000000000000 RCX: 0000000000000002
RDX: ffff888023f19cc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff8fa40b10 R08: ffff888023f19cc0 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: 00000000fffffff1
R13: ffff888108032800 R14: dffffc0000000000 R15: ffff888108032818
FS:  00007f38d496c6c0(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001200 CR3: 000000011d5d0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 fq_change+0xeba/0x2030
 fq_init+0x699/0x960
 qdisc_create+0x7ac/0xea0
 tc_modify_qdisc+0x1538/0x20e0
 rtnetlink_rcv_msg+0x77c/0xb70
 netlink_rcv_skb+0x208/0x470
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f38d3b8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f38d496c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f38d3db5fa0 RCX: 00007f38d3b8ebe9
RDX: 0000000000000040 RSI: 0000200000001200 RDI: 000000000000000e
RBP: 00007f38d3c11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f38d3db6038 R14: 00007f38d3db5fa0 R15: 00007ffe1ab85758
 </TASK>
