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: 6001 Comm: syz.1.509 Not tainted 6.1.147-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 38 c3 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 15 c3 82 f9 48 ba 00 00 00 00 00 fc
RSP: 0000:ffffc9000d8c7380 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92001b18ee8 RCX: 1ffff1100f6d945a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000d8c74d0 R08: dffffc0000000000 R09: fffffbfff215ba76
R10: fffffbfff215ba76 R11: 1ffffffff215ba75 R12: 0000000000000000
R13: ffff888023570000 R14: 0000000000000000 R15: 0000000000000000
FS:  000055559003d500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000200 CR3: 000000002ff9f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 qdisc_enqueue include/net/sch_generic.h:816 [inline]
 sfb_enqueue+0x9e0/0x17d0 net/sched/sch_sfb.c:405
 dev_qdisc_enqueue+0x4c/0x2b0 net/core/dev.c:3863
 __dev_xmit_skb net/core/dev.c:3952 [inline]
 __dev_queue_xmit+0xf8e/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_bearer_xmit_skb+0x2a9/0x3f0 net/tipc/bearer.c:577
 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+0x52/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7f1fb0a6eb8e
Code: 00 00 44 89 f9 49 8b 50 30 4c 89 f0 49 03 14 ca 80 3d 2d 90 34 00 00 49 89 d6 48 89 d5 74 28 25 ff 0f 00 00 83 f0 3d 8d 04 c0 <89> c5 c1 ed 04 31 c5 69 ed 2d eb d4 27 89 e8 c1 e8 0f 31 c5 81 e5
RSP: 002b:00007ffdff26db80 EFLAGS: 00000202
RAX: 00000000000060e4 RBX: 00007f1fb18e5720 RCX: 000000000001460d
RDX: ffffffff820401ec RSI: ffffffff8203cab7 RDI: 0000000000000011
RBP: ffffffff820401ec R08: 00007f1fb0db6038 R09: 00007f1fb0da2000
R10: 00007f1faffff008 R11: 0000000000000011 R12: 0000000000000011
R13: 0000000000000000 R14: ffffffff820401ec R15: 000000000001460d
 </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 38 c3 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 15 c3 82 f9 48 ba 00 00 00 00 00 fc
RSP: 0000:ffffc9000d8c7380 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92001b18ee8 RCX: 1ffff1100f6d945a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000d8c74d0 R08: dffffc0000000000 R09: fffffbfff215ba76
R10: fffffbfff215ba76 R11: 1ffffffff215ba75 R12: 0000000000000000
R13: ffff888023570000 R14: 0000000000000000 R15: 0000000000000000
FS:  000055559003d500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000200 CR3: 000000002ff9f000 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 38 c3 82 f9       	call   0xf982c34d
  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 15 c3 82 f9       	call   0xf982c34d
  38:	48                   	rex.W
  39:	ba 00 00 00 00       	mov    $0x0,%edx
  3e:	00 fc                	add    %bh,%ah