watchdog: BUG: soft lockup - CPU#1 stuck for 131s! [syz.3.13627:16527] Modules linked in: CPU: 1 PID: 16527 Comm: syz.3.13627 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:qdisc_match_from_root net/sched/sch_api.c:267 [inline] RIP: 0010:qdisc_lookup+0xd2/0x4e0 net/sched/sch_api.c:304 Code: 86 03 00 00 45 8b 24 24 44 89 e6 83 e6 01 31 ff e8 73 ce b8 fd 41 83 e4 01 0f 85 88 00 00 00 4d 8d 66 38 4c 89 e0 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 8b 03 00 00 45 8b 24 24 44 89 e7 89 de RSP: 0018:ffffc900013ceec8 EFLAGS: 00000a06 RAX: 1ffff11021fb3687 RBX: 00000000ffff0000 RCX: 0000000000000002 RDX: ffff88810eb5bb40 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900013ceef8 R08: ffff88810eb5bb40 R09: 0000000000000002 R10: 00000000ffffffff R11: 0000000000000002 R12: ffff88810fd9b438 R13: dffffc0000000000 R14: ffff88810fd9b400 R15: ffff88811eb52000 FS: 00007f59b5abe6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c29105f CR3: 000000011e1d9000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: qdisc_tree_reduce_backlog+0x111/0x340 net/sched/sch_api.c:793 fq_codel_change+0xa27/0xe40 net/sched/sch_fq_codel.c:436 fq_codel_init+0x342/0xa20 net/sched/sch_fq_codel.c:473 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: 0033:0x7f59b7055fc9 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:00007f59b5abe038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f59b72acfa0 RCX: 00007f59b7055fc9 RDX: 0000000000000000 RSI: 0000200000000640 RDI: 0000000000000003 RBP: 00007f59b70d8f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f59b72ad038 R14: 00007f59b72acfa0 R15: 00007ffe69f8ba58 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