Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752400AbcLGMTY (ORCPT ); Wed, 7 Dec 2016 07:19:24 -0500 Received: from mail-pg0-f51.google.com ([74.125.83.51]:36222 "EHLO mail-pg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751764AbcLGMTX (ORCPT ); Wed, 7 Dec 2016 07:19:23 -0500 From: Amit Pundir To: Andrew Morton Cc: Rob Herring , John Stultz , Android Kernel Team , lkml , Daniel Micay Subject: [PATCH 1/2] config: android-recommended: disable aio support Date: Wed, 7 Dec 2016 17:49:07 +0530 Message-Id: <1481113148-29204-1-git-send-email-amit.pundir@linaro.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1676 Lines: 40 From: Daniel Micay The aio interface adds substantial attack surface for a feature that's not being exposed by Android at all. It's unlikely that anyone is using the kernel feature directly either. This feature is rarely used even on servers. The glibc POSIX aio calls really use thread pools. The lack of widespread usage also means this is relatively poorly audited/tested. The kernel's aio rarely provides performance benefits over using a thread pool and is quite incomplete in terms of system call coverage along with having edge cases where blocking can occur. Part of the performance issue is the fact that it only supports direct io, not buffered io. The existing API is considered fundamentally flawed and it's unlikely it will be expanded, but rather replaced: https://marc.info/?l=linux-aio&m=145255815216051&w=2 Since ext4 encryption means no direct io support, kernel aio isn't even going to work properly on Android devices using file-based encryption. Reviewed-at: https://android-review.googlesource.com/#/c/292158/ Signed-off-by: Daniel Micay Signed-off-by: Amit Pundir --- kernel/configs/android-recommended.config | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/configs/android-recommended.config b/kernel/configs/android-recommended.config index 297756b..4719871 100644 --- a/kernel/configs/android-recommended.config +++ b/kernel/configs/android-recommended.config @@ -1,4 +1,5 @@ # KEEP ALPHABETICALLY SORTED +# CONFIG_AIO is not set # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set # CONFIG_INPUT_MOUSE is not set # CONFIG_LEGACY_PTYS is not set -- 2.7.4