The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/kernel/+/aefb70020b8f583c0173dbe02b44e5a2ec354b7d

commit aefb70020b8f583c0173dbe02b44e5a2ec354b7d
Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Fri Apr 21 22:45:39 2017

BACKPORT: commoncap: don't alloc the credential unless needed in cap_task_prctl

In function cap_task_prctl(), we would allocate a credential
unconditionally and then check if we support the requested function.
If not we would release this credential with abort_creds() by using
RCU method. But on some archs such as powerpc, the sys_prctl is heavily
used to get/set the floating point exception mode. So the unnecessary
allocating/releasing of credential not only introduce runtime overhead
but also do cause OOM due to the RCU implementation.

This patch removes abort_creds() from cap_task_prctl() by calling
prepare_creds() only when we need to modify it.

Reported-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
(cherry picked from commit 6d6f3328422a3bc56b0d8dd026a5de845d2abfa7)
Signed-off-by: Jorge Lucangeli Obes <jorgelo@chromium.org>

BUG= chromium:712834 
TEST=Build kernel.

Change-Id: Ice2f0b04338dfd57d052200c90578723cf7f1ed6
Reviewed-on: https://chromium-review.googlesource.com/483560
Commit-Ready: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

[modify] https://crrev.com/aefb70020b8f583c0173dbe02b44e5a2ec354b7d/security/commoncap.c

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/kernel/+/4033228b638104c1620ab911ba814561cd76c1ec

commit 4033228b638104c1620ab911ba814561cd76c1ec
Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Sat Apr 22 04:57:56 2017

BACKPORT: commoncap: don't alloc the credential unless needed in cap_task_prctl

In function cap_task_prctl(), we would allocate a credential
unconditionally and then check if we support the requested function.
If not we would release this credential with abort_creds() by using
RCU method. But on some archs such as powerpc, the sys_prctl is heavily
used to get/set the floating point exception mode. So the unnecessary
allocating/releasing of credential not only introduce runtime overhead
but also do cause OOM due to the RCU implementation.

This patch removes abort_creds() from cap_task_prctl() by calling
prepare_creds() only when we need to modify it.

Reported-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
(cherry picked from commit 6d6f3328422a3bc56b0d8dd026a5de845d2abfa7)
Signed-off-by: Jorge Lucangeli Obes <jorgelo@chromium.org>

BUG= chromium:712834 
TEST=Build kernel.

Change-Id: Idf03be78e4207667e3dfaaed3c2df9142611c5b8
Reviewed-on: https://chromium-review.googlesource.com/483661
Commit-Ready: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

[modify] https://crrev.com/4033228b638104c1620ab911ba814561cd76c1ec/security/commoncap.c

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/kernel/+/bc0f488dcbd7e3caff6f2dc3c6d1050ee214ee8a

commit bc0f488dcbd7e3caff6f2dc3c6d1050ee214ee8a
Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Tue Apr 25 21:03:47 2017

BACKPORT: commoncap: don't alloc the credential unless needed in cap_task_prctl

In function cap_task_prctl(), we would allocate a credential
unconditionally and then check if we support the requested function.
If not we would release this credential with abort_creds() by using
RCU method. But on some archs such as powerpc, the sys_prctl is heavily
used to get/set the floating point exception mode. So the unnecessary
allocating/releasing of credential not only introduce runtime overhead
but also do cause OOM due to the RCU implementation.

This patch removes abort_creds() from cap_task_prctl() by calling
prepare_creds() only when we need to modify it.

Reported-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
(cherry picked from commit 6d6f3328422a3bc56b0d8dd026a5de845d2abfa7)
Signed-off-by: Jorge Lucangeli Obes <jorgelo@chromium.org>

BUG= chromium:712834 
TEST=Build kernel, deploy to device, boots successfully.

Change-Id: I0ad367c568ba4f74ac125f93a4615d6ebe173e66
Reviewed-on: https://chromium-review.googlesource.com/485819
Commit-Ready: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

[modify] https://crrev.com/bc0f488dcbd7e3caff6f2dc3c6d1050ee214ee8a/security/commoncap.c