device syzkaller0 entered promiscuous mode 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: 6346 Comm: syz.4.596 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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 45 fa 76 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 22 fa 76 f9 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc9000d6e7380 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff92001adcec0 RCX: 1ffff1100a9cc45a RDX: dffffc0000000000 RSI: 00000000000023cd RDI: 00000000000023ce RBP: ffffc9000d6e74d0 R08: ffffffff90af23bf R09: 1ffffffff215e477 R10: dffffc0000000000 R11: fffffbfff215e478 R12: 0000000000000000 R13: ffff8880295b9000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f6f2e7f66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000010000 CR3: 000000007b84d000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: qdisc_enqueue include/net/sch_generic.h:854 [inline] netem_dequeue+0xcbb/0x1390 net/sched/sch_netem.c:736 dequeue_skb net/sched/sch_generic.c:295 [inline] qdisc_restart net/sched/sch_generic.c:400 [inline] __qdisc_run+0x25a/0x1660 net/sched/sch_generic.c:418 __dev_xmit_skb net/core/dev.c:3995 [inline] __dev_queue_xmit+0x1121/0x3810 net/core/dev.c:4337 packet_snd net/packet/af_packet.c:3133 [inline] packet_sendmsg+0x3b95/0x4de0 net/packet/af_packet.c:3164 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] __sys_sendto+0x497/0x650 net/socket.c:2153 __do_sys_sendto net/socket.c:2165 [inline] __se_sys_sendto net/socket.c:2161 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2161 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: 0033:0x7f6f3059ce59 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:00007f6f2e7f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f6f30815fa0 RCX: 00007f6f3059ce59 RDX: 000000000000fdef RSI: 00002000000002c0 RDI: 0000000000000005 RBP: 00007f6f30632e6f R08: 0000200000000140 R09: 0000000000000014 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6f30816038 R14: 00007f6f30815fa0 R15: 00007ffd73a86928 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 45 fa 76 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 22 fa 76 f9 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc9000d6e7380 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff92001adcec0 RCX: 1ffff1100a9cc45a RDX: dffffc0000000000 RSI: 00000000000023cd RDI: 00000000000023ce RBP: ffffc9000d6e74d0 R08: ffffffff90af23bf R09: 1ffffffff215e477 R10: dffffc0000000000 R11: fffffbfff215e478 R12: 0000000000000000 R13: ffff8880295b9000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f6f2e7f66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000010000 CR3: 000000007b84d000 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 45 fa 76 f9 call 0xf976fa5a 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 22 fa 76 f9 call 0xf976fa5a 38: 48 rex.W 39: ba 00 00 00 00 mov $0x0,%edx 3e: 00 fc add %bh,%ah