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: 25439 Comm: syz.7.7184 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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 57 b7 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 57 b7 f9 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc900023e7680 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff9200047cf1c RCX: 1ffff1100efce05a RDX: dffffc0000000000 RSI: 0000000000000130 RDI: 0000000000000131 RBP: ffffc900023e77d8 R08: dffffc0000000000 R09: fffffbfff1ff7a32 R10: fffffbfff1ff7a32 R11: 1ffffffff1ff7a31 R12: 0000000000000000 R13: ffff8880763c2000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fbf6cc556c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c37073b CR3: 000000001d70e000 CR4: 00000000003506e0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: dev_qdisc_enqueue+0x48/0x210 net/core/dev.c:3852 __dev_xmit_skb net/core/dev.c:3936 [inline] __dev_queue_xmit+0xd7e/0x2ed0 net/core/dev.c:4253 packet_snd net/packet/af_packet.c:3089 [inline] packet_sendmsg+0x3d52/0x4fe0 net/packet/af_packet.c:3120 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] __sys_sendto+0x423/0x580 net/socket.c:2063 __do_sys_sendto net/socket.c:2075 [inline] __se_sys_sendto net/socket.c:2071 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2071 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: 0033:0x7fbf6e9edfc9 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:00007fbf6cc55038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fbf6ec44fa0 RCX: 00007fbf6e9edfc9 RDX: 000000000000000e RSI: 00002000000005c0 RDI: 0000000000000008 RBP: 00007fbf6ea70f91 R08: 00002000000001c0 R09: 0000000000000014 R10: 0000000000000040 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbf6ec45038 R14: 00007fbf6ec44fa0 R15: 00007ffdfe2ef478 Modules linked in: ---[ end trace 82dd15bef2ee7a5c ]--- 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 57 b7 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 57 b7 f9 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc900023e7680 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff9200047cf1c RCX: 1ffff1100efce05a RDX: dffffc0000000000 RSI: 0000000000000130 RDI: 0000000000000131 RBP: ffffc900023e77d8 R08: dffffc0000000000 R09: fffffbfff1ff7a32 R10: fffffbfff1ff7a32 R11: 1ffffffff1ff7a31 R12: 0000000000000000 R13: ffff8880763c2000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fbf6cc556c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c37073b CR3: 000000001d70e000 CR4: 00000000003506e0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 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 57 b7 f9 call 0xf9b757cd 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 57 b7 f9 call 0xf9b757cd 38: 48 rex.W 39: ba 00 00 00 00 mov $0x0,%edx 3e: 00 fc add %bh,%ah