rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=0d94/1/0x4000000000000000 softirq=93444/93456 fqs=5200
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:     6138          0            0
rcu: 	cputime:      303          0        52184   ==> 52490(ms)
rcu: 	(t=10500 jiffies g=64021 q=1541 ncpus=2)
CPU: 0 UID: 0 PID: 18279 Comm: syz.1.3296 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:check_preemption_disabled+0x35/0x120
Code: 48 8b 05 be ae 25 07 48 89 44 24 08 65 8b 05 c6 ae 25 07 65 8b 0d bb ae 25 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d 9b ae 25 07 <48> 3b 4c 24 08 0f 85 cc 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d e9
RSP: 0018:ffffc9000253f008 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: d643e2dfdc7b3100
RDX: ffff888027799cc0 RSI: ffffffff8be33ee0 RDI: ffffffff8be33ea0
RBP: 0000000000000001 R08: ffff888027799cc0 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000000 R12: ffff8880326dc038
R13: dffffc0000000000 R14: ffff888036bf2c00 R15: ffff888022c1c478
FS:  00007f0ec3c9d6c0(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0ec3c7bfc8 CR3: 0000000028b0e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 rcu_is_watching+0x15/0xb0
 rcu_read_lock_held+0x15/0x50
 qdisc_lookup_rcu+0x32b/0x6d0
 qdisc_tree_reduce_backlog+0x1b2/0x480
 hhf_change+0x805/0xb40
 hhf_init+0x213/0x950
 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: 0033:0x7f0ec2d8eba9
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:00007f0ec3c9d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0ec2fd5fa0 RCX: 00007f0ec2d8eba9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 00007f0ec2e11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0ec2fd6038 R14: 00007f0ec2fd5fa0 R15: 00007ffd169db968
 </TASK>
