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: 17572 Comm: syz.2.3904 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0xc80/0x1610 net/sched/sch_fq_codel.c:230
Code: 24 24 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 e5 69 70 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 c2 69 70 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc900001e0520 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff9200003c104 RCX: 1ffff1100e88335a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001e0670 R08: ffffffff90b1348f R09: 1ffffffff2162691
R10: dffffc0000000000 R11: fffffbfff2162692 R12: 0000000000000000
R13: ffff8880434e0000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fb7285b56c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f281a72aff8 CR3: 00000000627df000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 qdisc_enqueue include/net/sch_generic.h:855 [inline]
 tbf_enqueue+0x225/0x6e0 net/sched/sch_tbf.c:257
 dev_qdisc_enqueue+0x4c/0x2b0 net/core/dev.c:3900
 __dev_xmit_skb net/core/dev.c:3989 [inline]
 __dev_queue_xmit+0x1031/0x3810 net/core/dev.c:4337
 dev_queue_xmit include/linux/netdevice.h:3053 [inline]
 tipc_l2_send_msg+0x2f0/0x3b0 net/tipc/bearer.c:519
 tipc_bearer_xmit_skb+0x2a9/0x3f0 net/tipc/bearer.c:578
 tipc_disc_timeout+0x5e1/0x740 net/tipc/discover.c:340
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> df a9 1d f7 65 8b 05 e0 5a c7 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9000de075c0 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: 4d3204cdb6e7a200
RDX: dffffc0000000000 RSI: ffffffff8a8c1820 RDI: 0000000000000001
RBP: ffffc9000de07650 R08: ffffffff90b132ef R09: 1ffffffff216265d
R10: dffffc0000000000 R11: fffffbfff216265e R12: dffffc0000000000
R13: 0000000000000000 R14: ffff888026dc56c0 R15: 1ffff92001bc0eb8
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __wake_up_common_lock kernel/sched/wait.c:140 [inline]
 __wake_up_sync_key+0x128/0x190 kernel/sched/wait.c:208
 __unix_dgram_recvmsg+0x4b7/0xda0 net/unix/af_unix.c:2480
 ____sys_recvmsg+0x2c8/0x5b0 net/socket.c:-1
 ___sys_recvmsg+0x210/0x590 net/socket.c:2780
 do_recvmmsg+0x370/0x810 net/socket.c:2874
 __sys_recvmmsg net/socket.c:2953 [inline]
 __do_sys_recvmmsg net/socket.c:2976 [inline]
 __se_sys_recvmmsg net/socket.c:2969 [inline]
 __x64_sys_recvmmsg+0x195/0x250 net/socket.c:2969
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb72779e0d9
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:00007fb7285b5028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fb727a26090 RCX: 00007fb72779e0d9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007fb727835024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb727a26128 R14: 00007fb727a26090 R15: 00007ffd0c799ee8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
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+0xc80/0x1610 net/sched/sch_fq_codel.c:230
Code: 24 24 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 e5 69 70 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 c2 69 70 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc900001e0520 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff9200003c104 RCX: 1ffff1100e88335a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001e0670 R08: ffffffff90b1348f R09: 1ffffffff2162691
R10: dffffc0000000000 R11: fffffbfff2162692 R12: 0000000000000000
R13: ffff8880434e0000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fb7285b56c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f281a72aff8 CR3: 00000000627df000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	24 24                	and    $0x24,%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 e5 69 70 f9       	call   0xf97069fa
  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 c2 69 70 f9       	call   0xf97069fa
  38:	48                   	rex.W
  39:	ba 00 00 00 00       	mov    $0x0,%edx
  3e:	00 fc                	add    %bh,%ah