RBP: 00007f103ab2ae19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f103accf038 R14: 00007f103accefa0 R15: 00007ffe2e2c2cb8 watchdog: BUG: soft lockup - CPU#1 stuck for 123s! [syz.4.2009:7351] Modules linked in: CPU: 1 PID: 7351 Comm: syz.4.2009 Tainted: G W 5.10.240-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025 RIP: 0010:qdisc_tree_reduce_backlog+0xb9/0x340 net/sched/sch_api.c:791 Code: 8b 1b 89 de 83 e6 40 31 ff e8 83 f9 b8 fd 83 e3 40 0f 85 70 02 00 00 49 8d bf a8 00 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 <84> c0 0f 85 db 01 00 00 41 8b 87 a8 00 00 00 89 45 d0 49 83 c7 40 RSP: 0018:ffffc900041fef28 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002 RDX: ffff888135592780 RSI: 0000000000000000 RDI: ffff888119a510a8 RBP: ffffc900041fef70 R08: ffff888135592780 R09: 0000000000000002 R10: 00000000ffffffff R11: 0000000000000002 R12: 00000000fffffff1 R13: ffff888119a510cc R14: dffffc0000000000 R15: ffff888119a51000 FS: 00007f10395106c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001200 CR3: 0000000111f66000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: fq_change+0xb9e/0x10a0 net/sched/sch_fq.c:915 fq_init+0x3e3/0x5d0 net/sched/sch_fq.c:963 qdisc_create+0x780/0x1040 net/sched/sch_api.c:1265 tc_modify_qdisc+0x8da/0x14c0 net/sched/sch_api.c:1725 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2503 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2376 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2430 __sys_sendmsg net/socket.c:2459 [inline] __do_sys_sendmsg net/socket.c:2468 [inline] __se_sys_sendmsg net/socket.c:2466 [inline] __x64_sys_sendmsg+0x1e2/0x2a0 net/socket.c:2466 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f103aaa7be9 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:00007f1039510038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f103accefa0 RCX: 00007f103aaa7be9 RDX: 0000000000000000 RSI: 0000200000001200 RDI: 0000000000000005 RBP: 00007f103ab2ae19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f103accf038 R14: 00007f103accefa0 R15: 00007ffe2e2c2cb8 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] NMI backtrace for cpu 0 skipped: idling at default_idle+0x12/0x20 arch/x86/kernel/process.c:717