general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 0 PID: 12806 Comm: syz.1.2579 Not tainted 6.6.98-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:list_empty include/linux/list.h:373 [inline]
RIP: 0010:qfq_qlen_notify+0x29/0x70 net/sched/sch_qfq.c:1425
Code: 90 f3 0f 1e fa 41 57 41 56 53 48 89 f3 49 89 fe e8 2c 2a ef 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 09 6e 46 f9 49 8b 07 4c 39 f8 74 1c
RSP: 0018:ffffc900032a6da8 EFLAGS: 00010202
RAX: 000000000000000b RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffffc9000d03a000 RSI: 0000000000001972 RDI: 0000000000001973
RBP: dffffc0000000000 R08: ffff888024f15a00 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: 0000000000000000
R13: ffff88807e38c000 R14: ffff88807e38c000 R15: 0000000000000058
FS:  00007fa58a9506c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c359cdf CR3: 000000002da86000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 qdisc_tree_reduce_backlog+0x28b/0x470 net/sched/sch_api.c:810
 codel_change+0x974/0xdb0 net/sched/sch_codel.c:177
 codel_init+0x1fd/0x3e0 net/sched/sch_codel.c:196
 qdisc_create+0x8eb/0x1050 net/sched/sch_api.c:1322
 tc_modify_qdisc+0xb13/0x1be0 net/sched/sch_api.c:-1
 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2537
 netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline]
 netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa589b8e929
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:00007fa58a950038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fa589db5fa0 RCX: 00007fa589b8e929
RDX: 0000000000004000 RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007fa589c10ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa589db5fa0 R15: 00007ffc986d07e8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:list_empty include/linux/list.h:373 [inline]
RIP: 0010:qfq_qlen_notify+0x29/0x70 net/sched/sch_qfq.c:1425
Code: 90 f3 0f 1e fa 41 57 41 56 53 48 89 f3 49 89 fe e8 2c 2a ef 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 09 6e 46 f9 49 8b 07 4c 39 f8 74 1c
RSP: 0018:ffffc900032a6da8 EFLAGS: 00010202
RAX: 000000000000000b RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffffc9000d03a000 RSI: 0000000000001972 RDI: 0000000000001973
RBP: dffffc0000000000 R08: ffff888024f15a00 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: 0000000000000000
R13: ffff88807e38c000 R14: ffff88807e38c000 R15: 0000000000000058
FS:  00007fa58a9506c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c359cdf CR3: 000000002da86000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	f3 0f 1e fa          	endbr64
   5:	41 57                	push   %r15
   7:	41 56                	push   %r14
   9:	53                   	push   %rbx
   a:	48 89 f3             	mov    %rsi,%rbx
   d:	49 89 fe             	mov    %rdi,%r14
  10:	e8 2c 2a ef f8       	call   0xf8ef2a41
  15:	4c 8d 7b 58          	lea    0x58(%rbx),%r15
  19:	4c 89 f8             	mov    %r15,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 ff             	mov    %r15,%rdi
  33:	e8 09 6e 46 f9       	call   0xf9466e41
  38:	49 8b 07             	mov    (%r15),%rax
  3b:	4c 39 f8             	cmp    %r15,%rax
  3e:	74 1c                	je     0x5c