INFO: task syz.0.859:9024 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.859 state:D stack:25768 pid:9024 tgid:9023 ppid:5822 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5254 [inline]
__schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
__schedule_loop kernel/sched/core.c:6944 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6959
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
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:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:746
____sys_sendmsg+0x505/0x830 net/socket.c:2634
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2688
__sys_sendmsg net/socket.c:2720 [inline]
__do_sys_sendmsg net/socket.c:2725 [inline]
__se_sys_sendmsg net/socket.c:2723 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2723
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0e0a78efc9
RSP: 002b:00007f0e0b6df038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0e0a9e5fa0 RCX: 00007f0e0a78efc9
RDX: 0000000004000000 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 00007f0e0b6df090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f0e0a9e6038 R14: 00007f0e0a9e5fa0 R15: 00007ffda91089a8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/1:2/797:
#0: ffff88801b055948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x841/0x15d0 kernel/workqueue.c:3242
#1: ffffc900035e7ba0 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x868/0x15d0 kernel/workqueue.c:3243
#2: ffffffff8e3433f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#2: ffffffff8e3433f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
2 locks held by getty/5590:
#0: ffff8880348930a0 (&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.3.847/8992:
#0: ffffffff8f753c30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e629de8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.0.859/9024:
#0: ffffffff8f753c30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e629de8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.2.890/9122:
#0: ffffffff8f753c30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e629de8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
1 lock held by syz.4.977/9533:
1 lock held by syz.5.1596/12360:
#0: ffffffff8e3433f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e3433f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:337 [inline]
watchdog+0xfa9/0xff0 kernel/hung_task.c:500
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5179 Comm: syslogd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:check_preemption_disabled+0x63/0x120 lib/smp_processor_id.c:19
Code: 08 0f 85 cc 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 cc cc cc cc cc 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 <74> c8 65 4c 8b 3c 25 08 40 b8 92 41 f6 47 2f 04 74 0a 41 83 bf 58
RSP: 0018:ffffc90003077790 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffff8b6098b2 RCX: 0000000080000000
RDX: 1ffff1100666e6be RSI: ffffffff8daca1fd RDI: ffffffff8be0f0c0
RBP: ffffc90003077898 R08: ffffc90003077ab0 R09: ffffc90003077a60
R10: dffffc0000000000 R11: fffffbfff1f7e0ef R12: dffffc0000000000
R13: 1ffff1100666e6bd R14: 0000000000000a06 R15: 1ffff9200060ef00
FS: 00007fb4ad840c80(0000) GS:ffff888125b9c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5250117d60 CR3: 0000000045274000 CR4: 00000000003526f0
Call Trace:
lockdep_hardirqs_off+0xab/0x110 kernel/locking/lockdep.c:4495
trace_hardirqs_off+0x12/0x40 kernel/trace/trace_preemptirq.c:104
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
_raw_spin_lock_irqsave+0x82/0xf0 kernel/locking/spinlock.c:162
__skb_try_recv_datagram+0x14a/0x4d0 net/core/datagram.c:264
__unix_dgram_recvmsg+0x20f/0xd60 net/unix/af_unix.c:2590
sock_recvmsg_nosec net/socket.c:1082 [inline]
sock_recvmsg+0x22c/0x270 net/socket.c:1104
sock_read_iter+0x231/0x2f0 net/socket.c:1174
new_sync_read fs/read_write.c:491 [inline]
vfs_read+0x55a/0xa30 fs/read_write.c:572
ksys_read+0x145/0x250 fs/read_write.c:715
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb4ad990407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffdfa6124e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fb4ad840c80 RCX: 00007fb4ad990407
RDX: 00000000000000ff RSI: 0000560448e7d950 RDI: 0000000000000000
RBP: 0000560448e7d910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000560448e7d9db
R13: 0000000000000000 R14: 0000560448e7d950 R15: 000056040e775d98