INFO: task syz-executor.3:30971 blocked for more than 141 seconds.
      Not tainted 5.15.0-rc2-next-20210924-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:27216 pid:30971 ppid: 22775 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4955 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6236
 schedule+0xd3/0x270 kernel/sched/core.c:6315
 synchronize_rcu_expedited+0x473/0x620 kernel/rcu/tree_exp.h:852
 namespace_unlock+0x1af/0x410 fs/namespace.c:1448
 drop_collected_mounts fs/namespace.c:1935 [inline]
 put_mnt_ns fs/namespace.c:4344 [inline]
 put_mnt_ns+0x106/0x140 fs/namespace.c:4340
 free_nsproxy+0x43/0x4c0 kernel/nsproxy.c:191
 put_nsproxy include/linux/nsproxy.h:105 [inline]
 switch_task_namespaces+0xaf/0xd0 kernel/nsproxy.c:249
 do_exit+0xba9/0x2a30 kernel/exit.c:824
 do_group_exit+0x125/0x310 kernel/exit.c:922
 get_signal+0x47f/0x2160 kernel/signal.c:2868
 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:863
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f3dbc460709
RSP: 002b:00007f3db99d7218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f3dbc564f68 RCX: 00007f3dbc460709
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3dbc564f68
RBP: 00007f3dbc564f60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3dbc564f6c
R13: 00007ffed05029af R14: 00007f3db99d7300 R15: 0000000000022000
 </TASK>