rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=c104/1/0x4000000000000000 softirq=102685/102692 fqs=5246
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:     6039          0            0
rcu: 	cputime:      290          0        52194   ==> 52500(ms)
rcu: 	(t=10502 jiffies g=78377 q=1356 ncpus=2)
CPU: 0 UID: 0 PID: 23895 Comm: syz.1.6862 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:rcu_lockdep_current_cpu_online+0xe8/0x120
Code: 00 74 08 48 89 df e8 67 78 7c 00 4c 85 3b 75 1a 48 c7 c7 00 fd 13 8e be 04 00 00 00 e8 c1 7a 7c 00 83 3d aa 43 6d 0c 00 74 16 <b0> 01 65 ff 0d cf f6 f9 10 74 0f 5b 41 5e 41 5f c3 cc cc cc cc cc
RSP: 0018:ffffc90007c06f98 EFLAGS: 00000202
RAX: 1ffffffff1c27e8e RBX: ffffffff8e13f470 RCX: 5f58e8e4beaca000
RDX: ffff88811b448000 RSI: ffffffff8be33be0 RDI: ffff88804b03afa8
RBP: 0000000000000001 R08: ffff88811b448000 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: ffff888119ddd038
R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000001
FS:  00007f51b86cc6c0(0000) GS:ffff8880b8615000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000003000 CR3: 0000000029450000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 rcu_read_lock_held+0x1e/0x50
 qdisc_lookup_rcu+0x32b/0x6d0
 qdisc_tree_reduce_backlog+0x1b2/0x480
 sfq_init+0x1a0f/0x2530
 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+0x52d/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __sys_sendmmsg+0x227/0x430
 __x64_sys_sendmmsg+0xa0/0xc0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f51b778eba9
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:00007f51b86cc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f51b79d5fa0 RCX: 00007f51b778eba9
RDX: 040000000000009f RSI: 00002000000002c0 RDI: 000000000000000b
RBP: 00007f51b7811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f51b79d6038 R14: 00007f51b79d5fa0 R15: 00007fff27642fa8
 </TASK>
