watchdog: BUG: soft lockup - CPU#1 stuck for 53s! [syz.2.1440:5934]
Modules linked in:
CPU: 1 PID: 5934 Comm: syz.2.1440 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:qdisc_dev include/net/sch_generic.h:596 [inline]
RIP: 0010:qdisc_tree_reduce_backlog+0xdd/0x380 net/sched/sch_api.c:801
Code: 0f 85 ed 01 00 00 41 8b 9f a8 00 00 00 49 83 c7 40 4c 89 f8 48 c1 e8 03 4d 89 f5 42 80 3c 30 00 74 08 4c 89 ff e8 83 fb cd fd <4d> 8b 37 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 6a
RSP: 0018:ffffc90000c76ff8 EFLAGS: 00000246
RAX: 1ffff1102541f288 RBX: 0000000000000000 RCX: ffff88811663bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88812a0f94a8
RBP: ffffc90000c77040 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200018edfc R12: 00000000fffffff1
R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88812a0f9440
FS:  00007f3ec7f826c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ec95978c0 CR3: 0000000127655000 CR4: 00000000003506a0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 sfq_change net/sched/sch_sfq.c:737 [inline]
 sfq_init+0x1989/0x25a0 net/sched/sch_sfq.c:802
 qdisc_create+0x807/0x11a0 net/sched/sch_api.c:1273
 tc_modify_qdisc+0x8ce/0x1550 net/sched/sch_api.c:-1
 rtnetlink_rcv_msg+0x9fd/0xcb0 net/core/rtnetlink.c:5662
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2520
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5680
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x879/0xb80 net/netlink/af_netlink.c:1923
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2436
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg net/socket.c:2526 [inline]
 __x64_sys_sendmsg+0x201/0x2d0 net/socket.c:2526
 x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f3ec954a1d9
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:00007f3ec7f82028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3ec97d2090 RCX: 00007f3ec954a1d9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 00007f3ec95e1888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3ec97d2128 R14: 00007f3ec97d2090 R15: 00007ffee3802e48
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0x8ad/0x9e0 kernel/smp.c:969
Code: 0f b6 44 05 00 84 c0 0f 85 9b 00 00 00 41 8b 1f 89 de 83 e6 01 31 ff e8 a1 53 0a 00 83 e3 01 75 07 e8 e7 4f 0a 00 eb 42 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 10 41 f7
RSP: 0018:ffffc90000087860 EFLAGS: 00000293
RAX: ffffffff815f8b9f RBX: 0000000000000001 RCX: ffff888100272800
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000087978 R08: ffff8881f7038e57 R09: 1ffff1103ee071ca
R10: dffffc0000000000 R11: ffffed103ee071cb R12: ffff8881f7038e40
R13: 1ffff1103ee27845 R14: 0000000000000001 R15: ffff8881f713c228
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fea64c8042c CR3: 000000000660f000 CR4: 00000000003506b0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x43/0x80 kernel/smp.c:1134
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1442 [inline]
 text_poke_bp_batch+0x1d4/0x600 arch/x86/kernel/alternative.c:1642
 text_poke_flush arch/x86/kernel/alternative.c:1833 [inline]
 text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:1840
 arch_jump_label_transform_apply+0x15/0x30 arch/x86/kernel/jump_label.c:146
 __jump_label_update+0x38f/0x3b0 kernel/jump_label.c:459
 jump_label_update+0x39b/0x450 kernel/jump_label.c:830
 static_key_disable_cpuslocked+0xc5/0x1a0 kernel/jump_label.c:207
 static_key_disable+0x1a/0x30 kernel/jump_label.c:215
 toggle_allocation_gate+0x3af/0x440 mm/kfence/core.c:797
 process_one_work+0x6c8/0xbb0 kernel/workqueue.c:2328
 worker_thread+0xaa0/0x1250 kernel/workqueue.c:2475
 kthread+0x3f5/0x4f0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>