INFO: task syz.3.1426:13314 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1426 state:D stack:27560 pid:13314 tgid:13312 ppid:5635 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821
nfsd_nl_threads_set_doit+0x8c8/0x1100 fs/nfsd/nfsctl.c:1660
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x159/0x420 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+0x585/0x850 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:775 [inline]
__sock_sendmsg net/socket.c:790 [inline]
____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2684
___sys_sendmsg+0x190/0x1e0 net/socket.c:2738
__sys_sendmsg+0x160/0x210 net/socket.c:2770
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff931b9de99
RSP: 002b:00007ff932a5b028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff931e26090 RCX: 00007ff931b9de99
RDX: 0000000000040010 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007ff931c33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff931e26128 R14: 00007ff931e26090 R15: 00007ffc26a99ba8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8ebe5f80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ebe5f80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ebe5f80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by syz-executor/5634:
#0: ffff88807b2c20d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807b2c20d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807b2c20d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff88807b2c20d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by kworker/u10:8/8092:
#0: ffff88801f364940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc90005737d08 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
4 locks held by kworker/u10:23/8107:
#0: ffff88801caf6140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc90004fefd08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffffffff90a86408 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673
#3: ffffffff90a9f000 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#3: ffffffff90a9f000 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248
3 locks held by kworker/0:8/12886:
#0: ffff88801bc0b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000327fd08 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffffffff8ebf18f8 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3857
2 locks held by syz.3.1426/13313:
#0: ffffffff90b4dc08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x8c8/0x1100 fs/nfsd/nfsctl.c:1660
2 locks held by syz.3.1426/13314:
#0: ffffffff90b4dc08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x8c8/0x1100 fs/nfsd/nfsctl.c:1660
2 locks held by syz-executor/13585:
#0: ffff88805adaa0d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88805adaa0d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88805adaa0d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff88805adaa0d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.2.1515/13857:
#0: ffffffff90b4dc08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1964
2 locks held by syz.0.1577/14232:
#0: ffffffff90b4dc08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_svc_export_set_reqs_doit+0x8a/0x2f0 fs/nfsd/export.c:1057
2 locks held by syz-executor/14266:
#0: ffff888054cb20d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888054cb20d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888054cb20d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff888054cb20d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/14439:
#0: ffff888035c400d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888035c400d8 (&type->s_umount_key#55){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888035c400d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff888035c400d8 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f06f360 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
9 locks held by syz-executor/15564:
#0: ffff888036da8450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#1: ffff8880563e7880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
#2: ffff88802a7a4a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff88802a7a4a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
#3: ffffffff9000ce20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
#4: ffff88805be04128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#4: ffff88805be04128 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
#4: ffff88805be04128 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
#5: ffff888079ad3258 (&devlink->lock_key#3){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1e0 drivers/net/netdevsim/dev.c:1799
#6: ffffffff90a9f000 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x1a6/0x970 drivers/net/netdevsim/netdev.c:1191
#7: ffff88805be94e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2847 [inline]
#7: ffff88805be94e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x47f/0x2140 net/core/dev.c:12406
#8: ffffffff8ebf1a28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz.9.1754/15565:
#0: ffff88805b91f540 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#0: ffff88805b91f540 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:709
2 locks held by syz.9.1765/15642:
#0: ffffffff90a86408 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575
#1: ffffffff90a9f000 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#1: ffffffff90a9f000 (rtnl_mutex){+.+.}-{4:4}, at: unregister_netdevice_notifier_net+0x1c/0xf0 net/core/dev.c:2132
1 lock held by syz.5.1768/15651:
#0: ffffffff8ebf1a28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
1 lock held by dhcpcd/15657:
#0: ffff888033868260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff888033868260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf50 net/packet/af_packet.c:3204
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245