INFO: task syz.1.3927:21628 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.3927 state:D stack:27200 pid:21628 tgid:21623 ppid:19098 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5526 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7276
__schedule_loop kernel/sched/core.c:7353 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7368
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7425
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1919
genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2713
___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
__sys_sendmsg net/socket.c:2799 [inline]
__do_sys_sendmsg net/socket.c:2804 [inline]
__se_sys_sendmsg net/socket.c:2802 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f162139e159
RSP: 002b:00007f161f5f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1621626090 RCX: 00007f162139e159
RDX: 0000000000000004 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 00007f162143503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1621626128 R14: 00007f1621626090 R15: 00007ffc7ccb04e8
Showing all locks held in the system:
locks held by khungtaskd/31: 1, last CPU#1:
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:5/85: 2, last CPU#0:
#0: ffff888031f44940 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888031f44940 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888031f44940 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888031f44940 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc9000202fc40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000202fc40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000202fc40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc9000202fc40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by getty/5376: 2, on CPU#1:
#0: ffff8880356a60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz.2.3284/18945: 2, on CPU#0:
#0: ffffffff902c3628 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f09f500 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by syz.1.3927/21628: 2, on CPU#0:
#0: ffffffff902c3628 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f09f500 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1919
=============================================
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 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 85 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:__lock_acquire+0x950/0x2de0 kernel/locking/lockdep.c:5284
Code: 2d d7 0e 00 4d 89 f5 0f 85 22 02 00 00 48 83 7c 24 38 00 0f 84 b6 01 00 00 49 8b 45 f8 25 ff 1f 00 00 48 0f a3 05 60 5f f7 12 <0f> 83 62 01 00 00 48 69 c0 c8 00 00 00 48 8d 80 d0 94 3b 94 e9 81
RSP: 0018:ffffc9000202f6d8 EFLAGS: 00000007
RAX: 0000000000000782 RBX: 0000000022554529 RCX: 000000007c25c0f1
RDX: 000000005e7bc943 RSI: 0000000064c8d1c8 RDI: ffff88801d7d3e80
RBP: e9eb8ea700000000 R08: ffffffff8bab4d4f R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100ab66d18 R12: 0000000000004000
R13: ffff88801d7d4aa8 R14: ffff88801d7d4aa8 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff888124cd2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555a1de84168 CR3: 000000000eb48000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
rcu_read_lock include/linux/rcupdate.h:849 [inline]
batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:870 [inline]
batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:949 [inline]
batadv_iv_ogm_schedule+0x440/0xfc0 net/batman-adv/bat_iv_ogm.c:1011
batadv_iv_send_outstanding_bat_ogm_packet+0x622/0x740 net/batman-adv/bat_iv_ogm.c:1924
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245