INFO: task syz.1.1946:14939 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1946 state:D stack:27544 pid:14939 tgid:14933 ppid:5837 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5248 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6855
__schedule_loop kernel/sched/core.c:6937 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6952
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7009
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xcf8/0x1b10 kernel/locking/mutex.c:776
nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1590
genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:733 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2608
___sys_sendmsg+0x134/0x1d0 net/socket.c:2662
__sys_sendmsg+0x16d/0x220 net/socket.c:2694
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd0de78f7c9
RSP: 002b:00007fd0df5e4038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd0de9e6090 RCX: 00007fd0de78f7c9
RDX: 0000000000004000 RSI: 0000200000000480 RDI: 0000000000000003
RBP: 00007fd0de813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd0de9e6128 R14: 00007fd0de9e6090 R15: 00007ffe87838268
INFO: task syz.2.1960:15029 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1960 state:D stack:27544 pid:15029 tgid:15021 ppid:5835 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5248 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6855
__schedule_loop kernel/sched/core.c:6937 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6952
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7009
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xcf8/0x1b10 kernel/locking/mutex.c:776
nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:733 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2608
___sys_sendmsg+0x134/0x1d0 net/socket.c:2662
__sys_sendmsg+0x16d/0x220 net/socket.c:2694
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f16ceb8f7c9
RSP: 002b:00007f16ccdd5038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f16cede6180 RCX: 00007f16ceb8f7c9
RDX: 0000000020000000 RSI: 0000200000005380 RDI: 0000000000000008
RBP: 00007f16cec13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f16cede6218 R14: 00007f16cede6180 R15: 00007fff72748648
Showing all locks held in the system:
6 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/31:
#0: ffffffff8e1c95a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e1c95a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e1c95a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/12138:
#0: ffff888034a990a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90004da72f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz.0.1868/14547:
#0: ffffffff8ffbdcd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e5fbc68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
2 locks held by syz.1.1946/14939:
#0: ffffffff8ffbdcd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e5fbc68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1590
2 locks held by syz.2.1960/15029:
#0: ffffffff8ffbdcd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e5fbc68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
2 locks held by syz-executor/15140:
#0: ffff888021baa0e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff888021baa0e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff888021baa0e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff888021baa0e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e5fbc68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
4 locks held by syz-executor/15201:
2 locks held by syz.4.2035/15401:
#0: ffffffff8ffbdcd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e5fbc68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1590
2 locks held by syz-executor/15519:
#0: ffff888056f8a0e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff888056f8a0e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff888056f8a0e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff888056f8a0e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e5fbc68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
4 locks held by kworker/u8:7/15754:
#0: ffff88801ba9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3238
#1: ffffc90004567c90 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3239
#2: ffffffff8ff01bf0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x830 net/core/net_namespace.c:669
#3: ffffffff8ff18148 (rtnl_mutex){+.+.}-{4:4}, at: mpls_net_exit+0x83/0x350 net/mpls/af_mpls.c:2706
2 locks held by syz.9.2234/16452:
#0: ffff88801c3000e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88801c3000e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88801c3000e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88801c3000e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e5fbc68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
9 locks held by syz-executor/16662:
#0: ffff888030972420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff8880843f4888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888143f68f08 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888143f68f08 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f492f48 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
#4: ffff88807ad5b0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff88807ad5b0e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline]
#4: ffff88807ad5b0e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294
#5: ffff88807ad5c250 (&devlink->lock_key#4){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1d0 drivers/net/netdevsim/dev.c:1721
#6: ffffffff8ff18148 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x108/0x800 drivers/net/netdevsim/netdev.c:1173
#7: ffff888077e1cd38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline]
#7: ffff888077e1cd38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x19fe/0x2570 net/core/dev.c:12244
#8: ffffffff8e1d4bb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311
4 locks held by syz.6.2270/16724:
1 lock held by syz.3.2274/16737:
1 lock held by syz.3.2274/16739:
5 locks held by syz.0.2276/16746:
4 locks held by dhcpcd-run-hook/16765:
=============================================
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 lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/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+0xf14/0x1140 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246