TOMOYO: Fix race on updating profile's comment line.
TOMOYO: Fix race on updating profile's comment line.

In tomoyo_write_profile() since 2.6.34, a lock was by error missing when
replacing profile's comment line. If multiple threads attempted

  echo '0-COMMENT=comment' > /sys/kernel/security/tomoyo/profile

in parallel, garbage collector will fail to kfree() the old value.
Protect the replacement using a lock. Also, keep the old value rather than
replace with empty string when out of memory error has occurred.

Signed-off-by: Xiaochen Wang <0aed0f1ef488320e319a9a6b74684c2ad4dfaf94@gmail.com>
Signed-off-by: Tetsuo Handa <3d00b54ad717112934d0b63b7ac2975b44022a61@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <10d11de3abc355eabe955bb734f0f8e71da56e16@namei.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs