BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 2bc12067 P4D 2bc12067 PUD 2deeb067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 15626 Comm: syz-executor.4 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc9000ba574e8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 1ffff9200174ae9e RCX: ffffc90011ba8000
RDX: ffffc9000ba57520 RSI: 0000000000000012 RDI: ffff88801cb52000
RBP: ffff88801cb52000 R08: 00000000fffffff1 R09: 0000000000000400
R10: ffffffff871502f4 R11: 0000000000000000 R12: ffffffff89ca5f80
R13: dffffc0000000000 R14: 00000000ffff0000 R15: ffff8880280b7c00
FS:  00007f7d712ea700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000021047000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 htb_offload net/sched/sch_htb.c:1011 [inline]
 htb_select_queue+0x17f/0x2c0 net/sched/sch_htb.c:1349
 tc_modify_qdisc+0x44a/0x1990 net/sched/sch_api.c:1657
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2399
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x465b09
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7d712ea188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09
RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004
RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffe31161f5f R14: 00007f7d712ea300 R15: 0000000000022000
Modules linked in:
CR2: 0000000000000000
---[ end trace 9c4305b98d533691 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc9000ba574e8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 1ffff9200174ae9e RCX: ffffc90011ba8000
RDX: ffffc9000ba57520 RSI: 0000000000000012 RDI: ffff88801cb52000
RBP: ffff88801cb52000 R08: 00000000fffffff1 R09: 0000000000000400
R10: ffffffff871502f4 R11: 0000000000000000 R12: ffffffff89ca5f80
R13: dffffc0000000000 R14: 00000000ffff0000 R15: ffff8880280b7c00
FS:  00007f7d712ea700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcb4e6de6c CR3: 0000000021047000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400