rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=cf6c/1/0x4000000000000000 softirq=70439/70440 fqs=5201
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:     7075          0            0
rcu: 	cputime:      317          0        52127   ==> 52480(ms)
rcu: 	(t=10500 jiffies g=53777 q=1967 ncpus=2)
CPU: 0 UID: 0 PID: 16176 Comm: syz.0.2815 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_lookup_rcu+0x39/0x6d0
Code: f3 49 89 ff e8 98 f9 3a f8 31 ff 89 de e8 cf fd 3a f8 85 db 74 5d 49 bd 00 00 00 00 00 fc ff df 4d 8d b7 c8 04 00 00 4c 89 f0 <48> c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 04 6a 9e f8 4d 8b 36
RSP: 0018:ffffc90007bf6f10 EFLAGS: 00000286
RAX: ffff8880233d64c8 RBX: 00000000ffff0000 RCX: 0000000000000000
RDX: ffff888030c90000 RSI: 00000000ffff0000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffff888030c90000 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000000 R12: 00000000fffffff1
R13: dffffc0000000000 R14: ffff8880233d64c8 R15: ffff8880233d6000
FS:  00007f54639d06c0(0000) GS:ffff8880b8614000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4eb24f56c0 CR3: 00000000331b8000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 qdisc_tree_reduce_backlog+0x1b2/0x480
 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: 0033:0x7f5462b8ebe9
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:00007f54639d0038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5462dc6090 RCX: 00007f5462b8ebe9
RDX: 0000000000000000 RSI: 0000200000001200 RDI: 0000000000000006
RBP: 00007f5462c11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5462dc6128 R14: 00007f5462dc6090 R15: 00007ffed8a294e8
 </TASK>
