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: 12988 Comm: syz.6.2600 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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 b8 c9 81 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 95 c9 81 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc90000007500 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000000efc RCX: 1ffff1100eea245a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000007650 R08: dffffc0000000000 R09: fffffbfff215c47a
R10: fffffbfff215c47a R11: 1ffffffff215c479 R12: 0000000000000000
R13: ffff888047350000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f0ae680c6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000034c01000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
cbs_child_enqueue net/sched/sch_cbs.c:95 [inline]
cbs_enqueue_soft+0x1a8/0x270 net/sched/sch_cbs.c:128
dev_qdisc_enqueue+0x4c/0x2b0 net/core/dev.c:3875
__dev_xmit_skb net/core/dev.c:3964 [inline]
__dev_queue_xmit+0xf8e/0x3760 net/core/dev.c:4312
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+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5123
Code: 0f 84 3b 01 00 00 48 85 db 0f 85 5a 01 00 00 e9 e8 04 00 00 4c 8b 75 d0 4c 89 e7 e8 c0 00 c9 08 e8 8b b1 2e 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc900038a76d8 EFLAGS: 00000286
RAX: 4c3d16221c8bfa00 RBX: 0000000000000000 RCX: 4c3d16221c8bfa00
RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: ffffffff8adefca0
RBP: ffffc900038a7730 R08: dffffc0000000000 R09: ffffed10171c7559
R10: ffffed10171c7559 R11: 1ffff110171c7558 R12: ffff888055b45940
R13: dffffc0000000000 R14: ffff88801e6c8000 R15: ffff8880b8e3b590
context_switch kernel/sched/core.c:5247 [inline]
__schedule+0x10f4/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
snd_rawmidi_write+0x391/0xb00 sound/core/rawmidi.c:1605
do_loop_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x497/0xaf0 fs/read_write.c:863
vfs_writev fs/read_write.c:934 [inline]
do_writev+0x24e/0x410 fs/read_write.c:977
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0ae598ec29
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:00007f0ae680c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f0ae5bd5fa0 RCX: 00007f0ae598ec29
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000005
RBP: 00007f0ae5a11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0ae5bd6038 R14: 00007f0ae5bd5fa0 R15: 00007ffd8eb90cd8
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 b8 c9 81 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 95 c9 81 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc90000007500 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000000efc RCX: 1ffff1100eea245a
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000007650 R08: dffffc0000000000 R09: fffffbfff215c47a
R10: fffffbfff215c47a R11: 1ffffffff215c479 R12: 0000000000000000
R13: ffff888047350000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f0ae680c6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000034c01000 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 b8 c9 81 f9 call 0xf981c9cd
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 95 c9 81 f9 call 0xf981c9cd
38: 48 rex.W
39: ba 00 00 00 00 mov $0x0,%edx
3e: 00 fc add %bh,%ah