general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 5178 Comm: syz.2.271 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline]
RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline]
RIP: 0010:fq_codel_enqueue+0xd71/0x1600 net/sched/sch_fq_codel.c:230
Code: 24 08 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 24 73 ab f9 48 ba 00 00 00 00 00 fc ff df 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 e7 e8 01 73 ab f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000331f660 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000663f1c RCX: 1ffff1100c3d495a
RDX: dffffc0000000000 RSI: 0000000000000995 RDI: 0000000000000996
RBP: ffffc9000331f7b8 R08: ffffffff901d818f R09: 1ffffffff203b031
R10: dffffc0000000000 R11: fffffbfff203b032 R12: 0000000000000000
R13: ffff8880606a6000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fcaf38516c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 000000005391a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dev_qdisc_enqueue+0x48/0x210 net/core/dev.c:3865
 __dev_xmit_skb net/core/dev.c:3949 [inline]
 __dev_queue_xmit+0xc25/0x2f80 net/core/dev.c:4266
 packet_snd net/packet/af_packet.c:3089 [inline]
 packet_sendmsg+0x3dba/0x5060 net/packet/af_packet.c:3120
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2072
 __do_sys_sendto net/socket.c:2084 [inline]
 __se_sys_sendto net/socket.c:2080 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2080
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fcaf55f7e59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcaf3851028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fcaf5870fa0 RCX: 00007fcaf55f7e59
RDX: 000000000000fdef RSI: 00002000000002c0 RDI: 0000000000000005
RBP: 00007fcaf568dd6f R08: 0000200000000140 R09: 0000000000000014
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcaf5871038 R14: 00007fcaf5870fa0 R15: 00007ffe3595eb68
 </TASK>
Modules linked in:
---[ end trace 1efb83b48f3d3f8c ]---
RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline]
RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline]
RIP: 0010:fq_codel_enqueue+0xd71/0x1600 net/sched/sch_fq_codel.c:230
Code: 24 08 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 24 73 ab f9 48 ba 00 00 00 00 00 fc ff df 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 e7 e8 01 73 ab f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000331f660 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000663f1c RCX: 1ffff1100c3d495a
RDX: dffffc0000000000 RSI: 0000000000000995 RDI: 0000000000000996
RBP: ffffc9000331f7b8 R08: ffffffff901d818f R09: 1ffffffff203b031
R10: dffffc0000000000 R11: fffffbfff203b032 R12: 0000000000000000
R13: ffff8880606a6000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fcaf38516c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 000000005391a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	24 08                	and    $0x8,%al
   2:	48 8b 44 24 20       	mov    0x20(%rsp),%rax
   7:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1)
   b:	74 12                	je     0x1f
   d:	4c 89 ef             	mov    %r13,%rdi
  10:	e8 24 73 ab f9       	call   0xf9ab7339
  15:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  1c:	fc ff df
  1f:	4d 8b 65 00          	mov    0x0(%r13),%r12
  23:	4c 89 e0             	mov    %r12,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1) <-- trapping instruction
  2e:	74 12                	je     0x42
  30:	4c 89 e7             	mov    %r12,%rdi
  33:	e8 01 73 ab f9       	call   0xf9ab7339
  38:	48                   	rex.W
  39:	ba 00 00 00 00       	mov    $0x0,%edx
  3e:	00 fc                	add    %bh,%ah