configfs: dir.c fix possible recursive locking
configfs_register_subsystem() with default_groups triggers recursive locking.
it seems that mutex_lock_nested is needed.
=============================================
[ INFO: possible recursive locking detected ]
2.6.24-rc6 #141
---------------------------------------------
swapper/1 is trying to acquire lock:
(&sb->s_type->i_mutex_key#3){--..}, at: [<c40ca76f>] configfs_attach_group+0x4f/0x190
but task is already holding lock:
(&sb->s_type->i_mutex_key#3){--..}, at: [<c40ca9d5>] configfs_register_subsystem+0x55/0x130
other info that might help us debug this:
1 lock held by swapper/1:
#0: (&sb->s_type->i_mutex_key#3){--..}, at: [<c40ca9d5>] configfs_register_subsystem+0x55/0x130
stack backtrace:
Pid: 1, comm: swapper Not tainted 2.6.24-rc6 #141
[<c40053ba>] show_trace_log_lvl+0x1a/0x30
[<c4005e82>] show_trace+0x12/0x20
[<c400687e>] dump_stack+0x6e/0x80
[<c404ec72>] __lock_acquire+0xe62/0x1120
[<c404efb2>] lock_acquire+0x82/0xa0
[<c43fdad8>] mutex_lock_nested+0x98/0x2e0
[<c40ca76f>] configfs_attach_group+0x4f/0x190
[<c40caa46>] configfs_register_subsystem+0xc6/0x130
[<c45c8186>] init_netconsole+0x2b6/0x300
[<c45a75f2>] kernel_init+0x142/0x320
[<c4004fb3>] kernel_thread_helper+0x7/0x14
=======================
Signed-off-by: Joonwoo Park <joonwpark81@gmail.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
1 file changed