general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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+0xd2d/0x1590 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 e8 92 82 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 c5 92 82 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc900000071a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000000e84 RCX: 1ffff1100637f45a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000072f0 R08: dffffc0000000000 R09: fffffbfff215bc94
R10: fffffbfff215bc94 R11: 1ffffffff215bc93 R12: 0000000000000000
R13: ffff888026d20000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f84bbd812f8 CR3: 0000000063439000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 qdisc_enqueue include/net/sch_generic.h:816 [inline]
 netem_dequeue+0xcfc/0x13c0 net/sched/sch_netem.c:737
 dequeue_skb net/sched/sch_generic.c:292 [inline]
 qdisc_restart net/sched/sch_generic.c:397 [inline]
 __qdisc_run+0x247/0x15f0 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3958 [inline]
 __dev_queue_xmit+0x107e/0x3760 net/core/dev.c:4300
 dev_queue_xmit include/linux/netdevice.h:3051 [inline]
 tipc_l2_send_msg+0x30f/0x3d0 net/tipc/bearer.c:518
 tipc_crypto_xmit+0x1a00/0x2440 net/tipc/crypto.c:1721
 tipc_bearer_xmit_skb+0x242/0x3f0 net/tipc/bearer.c:574
 tipc_disc_timeout+0x568/0x6b0 net/tipc/discover.c:338
 call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 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:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 b7 91 b0 f7 e9 4c ff ff ff e8 2d 08 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d b7 55 66 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c807d88 EFLAGS: 000002c6
RAX: 4c87ab11ff597000 RBX: ffffffff8a204e37 RCX: 4c87ab11ff597000
RDX: 0000000000000001 RSI: ffffffff8a8c0420 RDI: ffffffff8adef6a0
RBP: ffffffff8c807ec0 R08: dffffc0000000000 R09: ffffed10171c6af6
R10: ffffed10171c6af6 R11: 1ffff110171c6af5 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8c8bc680 R15: 1ffffffff1c3ead6
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1fc/0x570 kernel/sched/idle.c:303
 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
 rest_init+0x2dc/0x300 init/main.c:733
 arch_call_rest_init+0xa/0xa init/main.c:893
 start_kernel+0x490/0x539 init/main.c:1140
 secondary_startup_64_no_verify+0xcf/0xdb
 </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+0xd2d/0x1590 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 e8 92 82 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 c5 92 82 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc900000071a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000000e84 RCX: 1ffff1100637f45a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000072f0 R08: dffffc0000000000 R09: fffffbfff215bc94
R10: fffffbfff215bc94 R11: 1ffffffff215bc93 R12: 0000000000000000
R13: ffff888026d20000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f84bbd812f8 CR3: 0000000063439000 CR4: 00000000003506f0
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 e8 92 82 f9       	call   0xf98292fd
  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 c5 92 82 f9       	call   0xf98292fd
  38:	48                   	rex.W
  39:	ba 00 00 00 00       	mov    $0x0,%edx
  3e:	00 fc                	add    %bh,%ah