Oops: general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 1 UID: 0 PID: 7684 Comm: syz.1.515 Not tainted 6.16.0-rc3-syzkaller-00159-g223e2288f4b8-dirty #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:qfq_qlen_notify+0x29/0x70
Code: 90 f3 0f 1e fa 41 57 41 56 53 48 89 f3 49 89 fe e8 5c b0 3f f8 4c 8d 7b 58 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 f9 33 a3 f8 49 8b 07 4c 39 f8 74 1c
RSP: 0018:ffffc9000665f088 EFLAGS: 00010202
RAX: 000000000000000b RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffffc900035c1000 RSI: 000000000000031c RDI: 000000000000031d
RBP: dffffc0000000000 R08: ffff88801fa68000 R09: 0000000000000002
R10: 00000000ffffffff R11: ffffffff89809e00 R12: 0000000000000000
R13: ffff888110df0000 R14: ffff888110df0000 R15: 0000000000000058
FS:  00007f839dde96c0(0000) GS:ffff8881a3c50000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2c121f CR3: 0000000112c90000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 qdisc_tree_reduce_backlog+0x29c/0x480
 fq_codel_change+0xa96/0xef0
 fq_codel_init+0x355/0x960
 qdisc_create+0x7ac/0xea0
 tc_modify_qdisc+0x1426/0x2010
 rtnetlink_rcv_msg+0x77c/0xb70
 netlink_rcv_skb+0x208/0x470
 netlink_unicast+0x75b/0x8d0
 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: 0033:0x7f839cf8e929
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:00007f839dde9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f839d1b5fa0 RCX: 00007f839cf8e929
RDX: 0000000004008000 RSI: 0000200000000200 RDI: 0000000000000007
RBP: 00007f839d010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f839d1b5fa0 R15: 00007fffdb4e9b28
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:qfq_qlen_notify+0x29/0x70
Code: 90 f3 0f 1e fa 41 57 41 56 53 48 89 f3 49 89 fe e8 5c b0 3f f8 4c 8d 7b 58 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 f9 33 a3 f8 49 8b 07 4c 39 f8 74 1c
RSP: 0018:ffffc9000665f088 EFLAGS: 00010202
RAX: 000000000000000b RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffffc900035c1000 RSI: 000000000000031c RDI: 000000000000031d
RBP: dffffc0000000000 R08: ffff88801fa68000 R09: 0000000000000002
R10: 00000000ffffffff R11: ffffffff89809e00 R12: 0000000000000000
R13: ffff888110df0000 R14: ffff888110df0000 R15: 0000000000000058
FS:  00007f839dde96c0(0000) GS:ffff8881a3c50000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2c121f CR3: 0000000112c90000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
