INFO: task syz-executor:5839 blocked for more than 143 seconds.
Tainted: G I syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:23272 pid:5839 tgid:5839 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1347
deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
deactivate_super fs/super.c:506 [inline]
deactivate_super+0xde/0x100 fs/super.c:502
cleanup_mnt+0x225/0x450 fs/namespace.c:1327
task_work_run+0x150/0x240 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x419/0x4b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2c259901f7
RSP: 002b:00007ffdb1d4ea48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f2c25a11d7d RCX: 00007f2c259901f7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffdb1d4eb00
RBP: 00007ffdb1d4eb00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffdb1d4fb90
R13: 00007f2c25a11d7d R14: 000000000004573f R15: 00007ffdb1d4fbd0
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e1c3fa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e1c3fa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e1c3fa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
3 locks held by kworker/1:1/43:
#0: ffff88801b059948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc90000b37d10 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff8e1cf400 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3815
2 locks held by syz-executor/5839:
#0: ffff88807d6d20e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88807d6d20e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88807d6d20e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff88807d6d20e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e5eb648 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
2 locks held by kworker/0:4/5890:
2 locks held by syz.2.341/7607:
#0: ffffffff8ff8b0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e5eb648 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1590
1 lock held by syz-executor/7711:
#0: ffffffff8e1cf538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by getty/7773:
#0: ffff88814cd470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900031502f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/8795:
#0: ffff88807e1f60e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88807e1f60e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88807e1f60e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff88807e1f60e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e5eb648 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
2 locks held by syz-executor/9671:
#0: ffff888078cbe0e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff888078cbe0e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff888078cbe0e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff888078cbe0e0 (&type->s_umount_key#54){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e5eb648 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
1 lock held by syz-executor/10902:
#0: ffffffff8e1cf538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz.5.868/11161:
#0: ffff88805a3fbb88 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:979 [inline]
#0: ffff88805a3fbb88 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:661
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G I syzkaller #0 PREEMPT(full)
Tainted: [I]=FIRMWARE_WORKAROUND
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148
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: 11050 Comm: syz.6.865 Tainted: G I syzkaller #0 PREEMPT(full)
Tainted: [I]=FIRMWARE_WORKAROUND
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:lock_release+0x7f/0x2f0 kernel/locking/lockdep.c:5881
Code: 25 01 00 00 65 8b 05 28 6b e3 11 85 c0 0f 85 16 01 00 00 65 4c 8b 35 68 29 e3 11 41 8b b6 2c 0b 00 00 85 f6 0f 85 ff 00 00 00 <48> 81 3b 40 c5 80 93 0f 84 f2 00 00 00 9c 41 5d fa 48 c7 c7 60 27
RSP: 0018:ffffc9002477f450 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8e1c3fa0 RCX: ffffc90024780001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000002 R11: 00000000000134f7 R12: ffffffff816a58f4
R13: ffffc9002477f508 R14: ffff888032540000 R15: ffffc9002477f53c
FS: 0000000000000000(0000) GS:ffff888124f7f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faa449cc9a0 CR3: 000000007faa6000 CR4: 00000000003526f0
Call Trace:
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
class_rcu_destructor include/linux/rcupdate.h:1169 [inline]
unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:559
__call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3123
dentry_free+0xc2/0x160 fs/dcache.c:442
__dentry_kill+0x498/0x600 fs/dcache.c:688
shrink_kill fs/dcache.c:1114 [inline]
shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1141
shrink_dcache_parent+0xe1/0x530 fs/dcache.c:1575
do_one_tree fs/dcache.c:1604 [inline]
shrink_dcache_for_umount+0xa5/0x3e0 fs/dcache.c:1621
generic_shutdown_super+0x6c/0x390 fs/super.c:620
kill_anon_super fs/super.c:1281 [inline]
kill_litter_super+0x70/0xa0 fs/super.c:1291
deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
deactivate_super fs/super.c:506 [inline]
deactivate_super+0xde/0x100 fs/super.c:502
cleanup_mnt+0x225/0x450 fs/namespace.c:1327
task_work_run+0x150/0x240 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x86f/0x2bf0 kernel/exit.c:966
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x419/0x4b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faa43b8eec9
Code: Unable to access opcode bytes at 0x7faa43b8ee9f.
RSP: 002b:00007faa449cc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: fffffffffffffffc RBX: 00007faa43de6090 RCX: 00007faa43b8eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000080
RBP: 00007faa43c11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faa43de6128 R14: 00007faa43de6090 R15: 00007fff065fbc98