Oops: general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f] CPU: 1 UID: 0 PID: 6493 Comm: syz.0.146 Not tainted 6.16.0-rc5-syzkaller #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+0x32/0x230 net/sched/sch_qfq.c:1422 Code: 41 55 41 54 49 89 fc 55 53 48 89 f3 4c 8d 7b 58 48 83 ec 08 e8 1f b7 26 f8 4c 89 fa 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 67 01 00 00 48 8b 43 58 49 39 c7 0f 84 30 01 00 RSP: 0018:ffffc90003a57310 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000f7ad000 RDX: 000000000000000b RSI: ffffffff89952f91 RDI: ffff88804334c000 RBP: 00000000000afff2 R08: 0000000000000005 R09: 0000000000000000 R10: 00000000000afff2 R11: 0000000000000001 R12: ffff88804334c000 R13: 0000000000000000 R14: ffffffff8ce8f1e0 R15: 0000000000000058 FS: 00007f9bbe1846c0(0000) GS:ffff888124818000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 000000004403d000 CR4: 00000000003526f0 Call Trace: qdisc_tree_reduce_backlog+0x221/0x500 net/sched/sch_api.c:811 sfq_change net/sched/sch_sfq.c:740 [inline] sfq_init+0x88a/0x2540 net/sched/sch_sfq.c:804 qdisc_create+0x457/0xfc0 net/sched/sch_api.c:1324 __tc_modify_qdisc net/sched/sch_api.c:1749 [inline] tc_modify_qdisc+0x12bb/0x2130 net/sched/sch_api.c:1813 rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6953 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmsg+0x16d/0x220 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9bbd38e929 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:00007f9bbe184038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f9bbd5b6240 RCX: 00007f9bbd38e929 RDX: 0000000000004000 RSI: 0000200000000040 RDI: 000000000000000e RBP: 00007f9bbd410b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f9bbd5b6240 R15: 00007ffe24380958 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:list_empty include/linux/list.h:373 [inline] RIP: 0010:qfq_qlen_notify+0x32/0x230 net/sched/sch_qfq.c:1422 Code: 41 55 41 54 49 89 fc 55 53 48 89 f3 4c 8d 7b 58 48 83 ec 08 e8 1f b7 26 f8 4c 89 fa 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 67 01 00 00 48 8b 43 58 49 39 c7 0f 84 30 01 00 RSP: 0018:ffffc90003a57310 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000f7ad000 RDX: 000000000000000b RSI: ffffffff89952f91 RDI: ffff88804334c000 RBP: 00000000000afff2 R08: 0000000000000005 R09: 0000000000000000 R10: 00000000000afff2 R11: 0000000000000001 R12: ffff88804334c000 R13: 0000000000000000 R14: ffffffff8ce8f1e0 R15: 0000000000000058 FS: 00007f9bbe1846c0(0000) GS:ffff888124818000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 000000004403d000 CR4: 00000000003526f0 ---------------- Code disassembly (best guess): 0: 41 55 push %r13 2: 41 54 push %r12 4: 49 89 fc mov %rdi,%r12 7: 55 push %rbp 8: 53 push %rbx 9: 48 89 f3 mov %rsi,%rbx c: 4c 8d 7b 58 lea 0x58(%rbx),%r15 10: 48 83 ec 08 sub $0x8,%rsp 14: e8 1f b7 26 f8 call 0xf826b738 19: 4c 89 fa mov %r15,%rdx 1c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 23: fc ff df 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 2e: 0f 85 67 01 00 00 jne 0x19b 34: 48 8b 43 58 mov 0x58(%rbx),%rax 38: 49 39 c7 cmp %rax,%r15 3b: 0f .byte 0xf 3c: 84 30 test %dh,(%rax) 3e: 01 00 add %eax,(%rax)