Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 0 UID: 0 PID: 6151 Comm: syz.3.51 Not tainted 6.16.0-rc4-syzkaller-01070-gd23647fd547b #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:qdisc_tree_reduce_backlog+0x223/0x480 net/sched/sch_api.c:806
Code: 89 ef e8 b0 0b ab f8 4d 89 ef 85 db 74 0d e8 34 8b 47 f8 4c 89 f5 e9 88 00 00 00 48 8b 6d 00 48 8d 45 20 48 89 c3 48 c1 eb 03 <42> 80 3c 33 00 48 89 04 24 74 0d 48 8b 3c 24 e8 79 0b ab f8 48 8b
RSP: 0018:ffffc9000b92efe8 EFLAGS: 00010202
RAX: 0000000000000020 RBX: 0000000000000004 RCX: 0000000000000002
RDX: ffff88802b549e00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88802b549e00 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: 00000000000affe0
R13: ffff88807b685800 R14: dffffc0000000000 R15: ffff88807b685800
FS:  00007f832efa76c0(0000) GS:ffff888125c14000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c345967 CR3: 000000002664e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 fq_change+0x1519/0x1f50 net/sched/sch_fq.c:1147
 fq_init+0x699/0x960 net/sched/sch_fq.c:1201
 qdisc_create+0x7ac/0xea0 net/sched/sch_api.c:1324
 __tc_modify_qdisc net/sched/sch_api.c:1749 [inline]
 tc_modify_qdisc+0x1426/0x2010 net/sched/sch_api.c:1813
 rtnetlink_rcv_msg+0x779/0xb70 net/core/rtnetlink.c:6955
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f832e18e929
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:00007f832efa7038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f832e3b5fa0 RCX: 00007f832e18e929
RDX: 0000000000004000 RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007f832e210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f832e3b5fa0 R15: 00007ffe19d804d8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:qdisc_tree_reduce_backlog+0x223/0x480 net/sched/sch_api.c:806
Code: 89 ef e8 b0 0b ab f8 4d 89 ef 85 db 74 0d e8 34 8b 47 f8 4c 89 f5 e9 88 00 00 00 48 8b 6d 00 48 8d 45 20 48 89 c3 48 c1 eb 03 <42> 80 3c 33 00 48 89 04 24 74 0d 48 8b 3c 24 e8 79 0b ab f8 48 8b
RSP: 0018:ffffc9000b92efe8 EFLAGS: 00010202
RAX: 0000000000000020 RBX: 0000000000000004 RCX: 0000000000000002
RDX: ffff88802b549e00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88802b549e00 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: 00000000000affe0
R13: ffff88807b685800 R14: dffffc0000000000 R15: ffff88807b685800
FS:  00007f832efa76c0(0000) GS:ffff888125c14000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c345967 CR3: 000000002664e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	89 ef                	mov    %ebp,%edi
   2:	e8 b0 0b ab f8       	call   0xf8ab0bb7
   7:	4d 89 ef             	mov    %r13,%r15
   a:	85 db                	test   %ebx,%ebx
   c:	74 0d                	je     0x1b
   e:	e8 34 8b 47 f8       	call   0xf8478b47
  13:	4c 89 f5             	mov    %r14,%rbp
  16:	e9 88 00 00 00       	jmp    0xa3
  1b:	48 8b 6d 00          	mov    0x0(%rbp),%rbp
  1f:	48 8d 45 20          	lea    0x20(%rbp),%rax
  23:	48 89 c3             	mov    %rax,%rbx
  26:	48 c1 eb 03          	shr    $0x3,%rbx
* 2a:	42 80 3c 33 00       	cmpb   $0x0,(%rbx,%r14,1) <-- trapping instruction
  2f:	48 89 04 24          	mov    %rax,(%rsp)
  33:	74 0d                	je     0x42
  35:	48 8b 3c 24          	mov    (%rsp),%rdi
  39:	e8 79 0b ab f8       	call   0xf8ab0bb7
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b