watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz.1.136:840] Modules linked in: CPU: 0 PID: 840 Comm: syz.1.136 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 RIP: 0010:qdisc_lookup+0x419/0x4d0 net/sched/sch_api.c:314 Code: 7c b2 4c 89 ff e8 27 a4 ec fd eb a8 e8 60 16 b2 fd eb 0c e8 59 16 b2 fd eb 08 e8 52 16 b2 fd 45 31 f6 4c 89 f0 48 83 c4 08 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 44 89 e1 80 e1 07 80 c1 03 38 c1 0f RSP: 0018:ffffc9000130ef38 EFLAGS: 00000296 RAX: ffff88811a38a000 RBX: 0000000000000000 RCX: ffff888119db8000 RDX: 0000000000000000 RSI: 00000000ffff0000 RDI: 00000000ffff0000 RBP: ffffc9000130ef58 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000261de8 R12: ffff8881073d4000 R13: dffffc0000000000 R14: ffff88811a38a000 R15: 00000000ffff0000 FS: 00007efd7c6b56c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efd7db332a0 CR3: 000000011a79d000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: qdisc_tree_reduce_backlog+0x10b/0x380 net/sched/sch_api.c:800 fq_change+0xc9f/0x11d0 net/sched/sch_fq.c:925 fq_init+0x3e3/0x5d0 net/sched/sch_fq.c:973 qdisc_create+0x84c/0x1220 net/sched/sch_api.c:1272 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: 0033:0x7efd7dc5db19 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:00007efd7c6b5028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007efd7dee3fa0 RCX: 00007efd7dc5db19 RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000000000000003 RBP: 00007efd7dcf5af8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efd7dee4038 R14: 00007efd7dee3fa0 R15: 00007fffe1251578 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 112 Comm: kworker/u4:2 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:229 [inline] RIP: 0010:smp_call_function_single+0x209/0x490 kernel/smp.c:517 Code: 48 44 89 f6 83 e6 01 31 ff e8 63 90 0a 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 9e 8c 0a 00 e9 a4 00 00 00 f3 90 44 24 48 01 00 00 00 0f 84 8f 00 00 00 e8 84 8c 0a 00 eb e9 e8 RSP: 0018:ffffc90000c47700 EFLAGS: 00000293 RAX: ffffffff815a2a3c RBX: 0000000000000000 RCX: ffff888112100000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000c477f0 R08: ffff8881f7057687 R09: 1ffff1103ee0aed0 R10: dffffc0000000000 R11: ffffed103ee0aed1 R12: dffffc0000000000 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff92000188ee4 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f796acfe000 CR3: 000000000640f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_call_function_many_cond+0x8f5/0x9d0 kernel/smp.c:653 smp_call_function_many kernel/smp.c:716 [inline] smp_call_function kernel/smp.c:738 [inline] on_each_cpu+0xab/0x180 kernel/smp.c:837 text_poke_sync arch/x86/kernel/alternative.c:1568 [inline] text_poke_bp_batch+0x1cb/0x5f0 arch/x86/kernel/alternative.c:1768 text_poke_flush arch/x86/kernel/alternative.c:1959 [inline] text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:1966 arch_jump_label_transform_apply+0x15/0x30 arch/x86/kernel/jump_label.c:126 __jump_label_update+0x38f/0x3b0 kernel/jump_label.c:459 jump_label_update+0x34c/0x3e0 kernel/jump_label.c:825 static_key_enable_cpuslocked+0x126/0x240 kernel/jump_label.c:177 static_key_enable+0x1a/0x30 kernel/jump_label.c:190 toggle_allocation_gate+0xba/0x440 mm/kfence/core.c:624 process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301 worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447 kthread+0x324/0x3b0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298