kthread+0x324/0x3b0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz.3.140:865]
Modules linked in:
CPU: 0 PID: 865 Comm: syz.3.140 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:qdisc_tree_reduce_backlog+0x179/0x380 net/sched/sch_api.c:803
Code: 08 4c 89 f7 e8 18 e2 ec fd 4d 89 e7 85 db 74 07 e8 3c 61 b2 fd eb 7a 4d 8b 36 49 8d 46 20 48 89 c3 48 c1 eb 03 42 80 3c 2b 00 <74> 0d 49 8d 7e 20 e8 ec e1 ec fd 49 8d 46 20 48 83 38 00 74 4d 48
RSP: 0018:ffffc90000c06f28 EFLAGS: 00000246
RAX: ffffffff857080c0 RBX: 1ffffffff0ae1018 RCX: 0000000000000002
RDX: ffff88811756bc00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000c06f70 R08: 1ffff11022b2dd02 R09: 1ffff11022b2dd12
R10: 1ffff11022b2dd01 R11: fffff52000180de0 R12: ffff8881165b2c00
R13: dffffc0000000000 R14: ffffffff857080a0 R15: ffff8881165b2c00
FS:  00007f64b25e56c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c304855 CR3: 0000000112a34000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 fq_codel_change+0xa6d/0xeb0 net/sched/sch_fq_codel.c:473
 fq_codel_init+0x33f/0xa40 net/sched/sch_fq_codel.c:510
 qdisc_create+0x84c/0x1220 net/sched/sch_api.c:1269
 tc_modify_qdisc+0x8c2/0x1470 net/sched/sch_api.c:-1
 rtnetlink_rcv_msg+0x9e9/0xca0 net/core/rtnetlink.c:5622
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2508
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5640
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x949/0xb70 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2377
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2431
 __sys_sendmsg net/socket.c:2460 [inline]
 __do_sys_sendmsg net/socket.c:2469 [inline]
 __se_sys_sendmsg net/socket.c:2467 [inline]
 __x64_sys_sendmsg+0x201/0x2d0 net/socket.c:2467
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f64b3bad159
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:00007f64b25e5028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f64b3e35090 RCX: 00007f64b3bad159
RDX: 0000000004040814 RSI: 0000200000000040 RDI: 000000000000000b
RBP: 00007f64b3c44024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f64b3e35128 R14: 00007f64b3e35090 R15: 00007ffe850fb648