v3.9-rc1: [BUG: swapper/1 still has locks held!]

[Shawn Guo]

I'm running v3.9-rc1 kernel on an ARM platform (i.MX28) with
arch/arm/mxs_defconfig and getting the following BUG warning.

Shawn

[    5.681034] =====================================
[    5.685885] [ BUG: swapper/1 still has locks held! ]
[    5.690885] 3.9.0-rc1 #774 Not tainted
[    5.694734] -------------------------------------
[    5.699475] 2 locks held by swapper/1:
[    5.703323]  #0:  (&sig->cred_guard_mutex){+.+.+.}, at: [<c00d20e0>] prepare_bprm_creds+0x28/0x64
[    5.712326]  #1:  (&type->i_mutex_dir_key){+.+.+.}, at: [<c00d5350>] lookup_slow+0x2c/0xa0
[    5.720966]
[    5.720966] stack backtrace:
[    5.725528] [<c0013c78>] (unwind_backtrace+0x0/0xf0) from [<c0426f94>] (rpc_wait_bit_killable+0x94/0xb4)
[    5.735184] [<c0426f94>] (rpc_wait_bit_killable+0x94/0xb4) from [<c044684c>] (__wait_on_bit+0x74/0xb8)
[    5.744645] [<c044684c>] (__wait_on_bit+0x74/0xb8) from [<c04468f4>] (out_of_line_wait_on_bit+0x64/0x70)
[    5.754278] [<c04468f4>] (out_of_line_wait_on_bit+0x64/0x70) from [<c0427e38>] (__rpc_execute+0xf4/0x370)
[    5.763991] [<c0427e38>] (__rpc_execute+0xf4/0x370) from [<c042124c>] (rpc_run_task+0xa4/0xb0)
[    5.772660] [<c042124c>] (rpc_run_task+0xa4/0xb0) from [<c0421350>] (rpc_call_sync+0x40/0xac)
[    5.781335] [<c0421350>] (rpc_call_sync+0x40/0xac) from [<c01c2e08>] (nfs3_rpc_wrapper.constprop.6+0x58/0xdc)
[    5.791406] [<c01c2e08>] (nfs3_rpc_wrapper.constprop.6+0x58/0xdc) from [<c01c2fbc>] (nfs3_proc_lookup+0x88/0xf4)
[    5.801751] [<c01c2fbc>] (nfs3_proc_lookup+0x88/0xf4) from [<c01b282c>] (nfs_lookup+0xe8/0x18c)
[    5.810659] [<c01b282c>] (nfs_lookup+0xe8/0x18c) from [<c00d49f8>] (lookup_real+0x20/0x50)
[    5.819097] [<c00d49f8>] (lookup_real+0x20/0x50) from [<c00d5314>] (__lookup_hash+0x34/0x44)
[    5.827696] [<c00d5314>] (__lookup_hash+0x34/0x44) from [<c00d5360>] (lookup_slow+0x3c/0xa0)
[    5.836297] [<c00d5360>] (lookup_slow+0x3c/0xa0) from [<c00d61bc>] (link_path_walk+0x2a4/0x848)
[    5.845144] [<c00d61bc>] (link_path_walk+0x2a4/0x848) from [<c00d9204>] (path_openat+0x278/0x444)
[    5.854176] [<c00d9204>] (path_openat+0x278/0x444) from [<c00d96cc>] (do_filp_open+0x2c/0x80)
[    5.862755] [<c00d96cc>] (do_filp_open+0x2c/0x80) from [<c00d12fc>] (open_exec+0x30/0x10c)
[    5.871166] [<c00d12fc>] (open_exec+0x30/0x10c) from [<c00d232c>] (do_execve+0x1b8/0x4c4)
[    5.879500] [<c00d232c>] (do_execve+0x1b8/0x4c4) from [<c0440b54>] (kernel_init+0x80/0xe4)
[    5.887963] [<c0440b54>] (kernel_init+0x80/0xe4) from [<c000e9c8>] (ret_from_fork+0x14/0x2c)