INFO: task syz-executor:5616 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-executor state:D stack:23400 pid:5616 tgid:5616 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7376
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccb/0x1bd0 kernel/locking/mutex.c:821
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1372
deactivate_locked_super+0xbd/0x130 fs/super.c:586
deactivate_super fs/super.c:614 [inline]
deactivate_super+0xea/0x110 fs/super.c:610
cleanup_mnt+0x21f/0x450 fs/namespace.c:1317
task_work_run+0x150/0x240 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1d8/0x700 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x603/0x770 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f4539f397
RSP: 002b:00007ffe7a3a2c48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5f454344bb RCX: 00007f5f4539f397
RDX: 0000000000000004 RSI: 0000000000000009 RDI: 00007ffe7a3a3d90
RBP: 00007ffe7a3a3d7c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe7a3a3d90
R13: 00007f5f454344bb R14: 00000000000d766c R15: 00007ffe7a3a3dd0
Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#0:
#0: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by getty/5380: 2, on CPU#0:
#0: ffff888032a5c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032262e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by syz-executor/5616: 2, on CPU#0:
#0: ffff88807c07c0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88807c07c0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88807c07c0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super fs/super.c:613 [inline]
#0: ffff88807c07c0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:610
#1: ffffffff8f288940 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
locks held by syz-executor/8199: 2, on CPU#0:
#0: ffff888022faa0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff888022faa0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff888022faa0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super fs/super.c:613 [inline]
#0: ffff888022faa0e8 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:610
#1: ffffffff8f288940 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
locks held by syz.0.2120/16432: 2, on CPU#0:
#0: ffffffff90d872c8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f288940 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x8c8/0x1100 fs/nfsd/nfsctl.c:1690
locks held by syz.1.2960/21043: 1, last CPU#0:
#0: ffff88807e2bc378 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
#0: ffff88807e2bc378 (&mm->mmap_lock){++++}-{4:4}, at: do_mprotect_pkey+0x254/0xdd0 mm/mprotect.c:902
locks held by syz.1.2960/21050: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x21e/0x780 net/ipv4/ip_tunnel.c:1136
locks held by syz.1.2960/21053: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: register_nexthop_notifier+0x1b/0x70 net/ipv4/nexthop.c:4044
locks held by syz.1.2960/21057: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x21e/0x780 net/ipv4/ip_tunnel.c:1136
locks held by syz.6.2963/21049: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x21e/0x780 net/ipv4/ip_tunnel.c:1136
locks held by syz.6.2963/21054: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: register_nexthop_notifier+0x1b/0x70 net/ipv4/nexthop.c:4044
locks held by syz.6.2963/21061: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2128
locks held by syz.4.2964/21048: 4, last CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x21e/0x780 net/ipv4/ip_tunnel.c:1136
#2: ffff88801d2c4980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x38/0xaa0 fs/kernfs/dir.c:825
#3: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#3: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: kernfs_root+0x23/0x2a0 fs/kernfs/kernfs-internal.h:76
locks held by syz.4.2964/21056: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffff88801d2c4980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x38/0xaa0 fs/kernfs/dir.c:825
locks held by syz.4.2964/21059: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2128
locks held by syz.5.2965/21055: 2, last CPU#0:
#0: ffff88807e2ba9f8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
#0: ffff88807e2ba9f8 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1f5/0x470 mm/util.c:579
#1: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x310 mm/pgtable-generic.c:290
locks held by syz.5.2965/21058: 2, last CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8edec2e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xbd/0x2090 arch/x86/kernel/unwind_orc.c:495
locks held by syz.5.2965/21060: 1, on CPU#0:
#0: ffff88807e2ba9f8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:609 [inline]
#0: ffff88807e2ba9f8 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:450 [inline]
#0: ffff88807e2ba9f8 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x160/0x6f0 mm/mmap_lock.c:501
locks held by syz.5.2965/21063: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2128
locks held by syz.5.2965/21066: 2, on CPU#0:
#0: ffffffff90cbefc8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x323/0x7a0 net/core/net_namespace.c:578
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#1: ffffffff90cd7bc0 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2128
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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:123
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 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+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+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245