Oops: general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f] CPU: 1 UID: 0 PID: 21481 Comm: syz.0.4721 Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:list_empty include/linux/list.h:373 [inline] RIP: 0010:qfq_qlen_notify+0x29/0x70 net/sched/sch_qfq.c:1422 Code: 90 f3 0f 1e fa 41 57 41 56 53 48 89 f3 49 89 fe e8 ac 6b 3f f8 4c 8d 7b 58 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 59 ee a2 f8 49 8b 07 4c 39 f8 74 1c RSP: 0018:ffffc9000468efc8 EFLAGS: 00010202 RAX: 000000000000000b RBX: 0000000000000000 RCX: dffffc0000000000 RDX: ffffc9000c37b000 RSI: 0000000000000b34 RDI: 0000000000000b35 RBP: dffffc0000000000 R08: ffff88802c5f8000 R09: 0000000000000002 R10: 00000000ffffffff R11: ffffffff8980e2e0 R12: 0000000000000000 R13: ffff888036988000 R14: ffff888036988000 R15: 0000000000000058 FS: 0000000000000000(0000) GS:ffff888125d50000(0063) knlGS:00000000f50aeb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000030117ff8 CR3: 000000007cd72000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: qdisc_tree_reduce_backlog+0x299/0x480 net/sched/sch_api.c:811 fq_change+0x1519/0x1f50 net/sched/sch_fq.c:1147 fq_init+0x699/0x960 net/sched/sch_fq.c:1201 qdisc_create+0x7a9/0xea0 net/sched/sch_api.c:1324 __tc_modify_qdisc net/sched/sch_api.c:1749 [inline] tc_modify_qdisc+0x1426/0x2010 net/sched/sch_api.c:1813 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6953 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 ____sys_sendmsg+0x505/0x830 net/socket.c:2566 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620 __sys_sendmsg+0x164/0x220 net/socket.c:2652 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70be539 Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f50ae55c EFLAGS: 00000206 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000080000200 RDX: 0000000004008000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:list_empty include/linux/list.h:373 [inline] RIP: 0010:qfq_qlen_notify+0x29/0x70 net/sched/sch_qfq.c:1422 Code: 90 f3 0f 1e fa 41 57 41 56 53 48 89 f3 49 89 fe e8 ac 6b 3f f8 4c 8d 7b 58 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 59 ee a2 f8 49 8b 07 4c 39 f8 74 1c RSP: 0018:ffffc9000468efc8 EFLAGS: 00010202 RAX: 000000000000000b RBX: 0000000000000000 RCX: dffffc0000000000 RDX: ffffc9000c37b000 RSI: 0000000000000b34 RDI: 0000000000000b35 RBP: dffffc0000000000 R08: ffff88802c5f8000 R09: 0000000000000002 R10: 00000000ffffffff R11: ffffffff8980e2e0 R12: 0000000000000000 R13: ffff888036988000 R14: ffff888036988000 R15: 0000000000000058 FS: 0000000000000000(0000) GS:ffff888125d50000(0063) knlGS:00000000f50aeb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000030117ff8 CR3: 000000007cd72000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 90 nop 1: f3 0f 1e fa endbr64 5: 41 57 push %r15 7: 41 56 push %r14 9: 53 push %rbx a: 48 89 f3 mov %rsi,%rbx d: 49 89 fe mov %rdi,%r14 10: e8 ac 6b 3f f8 call 0xf83f6bc1 15: 4c 8d 7b 58 lea 0x58(%rbx),%r15 19: 4c 89 f8 mov %r15,%rax 1c: 48 c1 e8 03 shr $0x3,%rax 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 27: fc ff df * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 ff mov %r15,%rdi 33: e8 59 ee a2 f8 call 0xf8a2ee91 38: 49 8b 07 mov (%r15),%rax 3b: 4c 39 f8 cmp %r15,%rax 3e: 74 1c je 0x5c