INFO: task syz.2.900:9504 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.900 state:D stack:25688 pid:9504 tgid:9502 ppid:5839 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
nfsd_nl_threads_set_doit+0x2cb/0x960 fs/nfsd/nfsctl.c:1590
genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:733
____sys_sendmsg+0x505/0x820 net/socket.c:2608
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2662
__sys_sendmsg net/socket.c:2694 [inline]
__do_sys_sendmsg net/socket.c:2699 [inline]
__se_sys_sendmsg net/socket.c:2697 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2697
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4e1b98f749
RSP: 002b:00007f4e19bf6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4e1bbe5fa0 RCX: 00007f4e1b98f749
RDX: 0000000000008004 RSI: 0000200000000180 RDI: 0000000000000009
RBP: 00007f4e1ba13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4e1bbe6038 R14: 00007f4e1bbe5fa0 R15: 00007ffe7e2a9f98
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5591:
#0: ffff88814cabd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/5836:
2 locks held by syz.1.251/7004:
#0: ffffffff8f35d170 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e233a08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1660 fs/nfsd/nfsctl.c:1880
2 locks held by syz.2.900/9504:
#0: ffffffff8f35d170 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e233a08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960 fs/nfsd/nfsctl.c:1590
2 locks held by syz.6.1442/11648:
#0: ffffffff8f35d170 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e233a08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960 fs/nfsd/nfsctl.c:1590
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3c/0xf80 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x97/0x130 kernel/kcov.c:351
Code: 54 53 48 8b 54 24 20 65 4c 8b 04 25 08 f0 76 92 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d b9 9f b5 10 <41> 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 41 83 b8 6c
RSP: 0018:ffffffff8dc071a0 EFLAGS: 00000012
RAX: 0000000000000020 RBX: 0000000000000004 RCX: 0000000000000005
RDX: ffffffff81c32a05 RSI: ffffffff8df99b60 RDI: 0000000000000004
RBP: 0000004c33dfccce R08: ffffffff8dc95280 R09: 000000000000000b
R10: 000000000000000b R11: 0000000000000005 R12: dffffc0000000000
R13: ffff88801a074010 R14: ffff88801a074880 R15: 00000000000b6bc4
FS: 0000000000000000(0000) GS:ffff8881260b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f815bbb42f8 CR3: 0000000023f82000 CR4: 00000000003526f0
Call Trace:
rb_event_length+0x45/0x400 kernel/trace/ring_buffer.c:222
rb_read_data_buffer+0x438/0x580 kernel/trace/ring_buffer.c:1823
check_buffer+0x28a/0x750 kernel/trace/ring_buffer.c:4394
__rb_reserve_next+0x592/0xdb0 kernel/trace/ring_buffer.c:4493
rb_reserve_next_event kernel/trace/ring_buffer.c:4630 [inline]
ring_buffer_lock_reserve+0xbb5/0x1010 kernel/trace/ring_buffer.c:4689
__trace_buffer_lock_reserve kernel/trace/trace.c:1081 [inline]
trace_event_buffer_lock_reserve+0x1d0/0x6f0 kernel/trace/trace.c:2799
trace_event_buffer_reserve+0x248/0x340 kernel/trace/trace_events.c:672
do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
trace_event_raw_event_bpf_trace_printk+0x100/0x260 kernel/trace/bpf_trace.h:11
__do_trace_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
trace_bpf_trace_printk+0x153/0x1b0 kernel/trace/bpf_trace.h:11
____bpf_trace_printk kernel/trace/bpf_trace.c:379 [inline]
bpf_trace_printk+0x11e/0x190 kernel/trace/bpf_trace.c:362
bpf_prog_65ca114971fc191b+0x38/0x40
bpf_dispatcher_nop_func include/linux/bpf.h:1376 [inline]
__bpf_prog_run include/linux/filter.h:723 [inline]
bpf_prog_run include/linux/filter.h:730 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run1+0x27f/0x4c0 kernel/trace/bpf_trace.c:2115
__bpf_trace_rcu_utilization+0xa1/0xf0 include/trace/events/rcu.h:27
__do_trace_rcu_utilization include/trace/events/rcu.h:27 [inline]
trace_rcu_utilization+0x191/0x1c0 include/trace/events/rcu.h:27
rcu_note_context_switch+0xdb8/0x1120 kernel/rcu/tree_plugin.h:372
__schedule+0x346/0x5000 kernel/sched/core.c:6748
schedule_idle+0x52/0x90 kernel/sched/core.c:6986
do_idle+0x4b3/0x520 kernel/sched/idle.c:360
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3ae/0x410 init/main.c:1111
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147