From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [alternative-merged] add-kernel-config-option-for-twisting-kernel-behavior.patch removed from -mm tree Date: Thu, 28 May 2020 12:11:52 -0700 Message-ID: <20200528191152.6G9NSTXFa%akpm@linux-foundation.org> References: <20200527222015.62ba8592af63dae12ab58ffe@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:45270 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406165AbgE1TLy (ORCPT ); Thu, 28 May 2020 15:11:54 -0400 In-Reply-To: <20200527222015.62ba8592af63dae12ab58ffe@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: ak@linux.intel.com, arnd@arndb.de, dvyukov@google.com, gregkh@linuxfoundation.org, jslaby@suse.com, mjg59@google.com, mm-commits@vger.kernel.org, penguin-kernel@I-love.SAKURA.ne.jp, peterz@infradead.org, pmladek@suse.com, rostedt@goodmis.org, sergey.senozhatsky@gmail.com, tytso@mit.edu, viro@zeniv.linux.org.uk The patch titled Subject: add kernel config option for twisting kernel behavior. has been removed from the -mm tree. Its filename was add-kernel-config-option-for-twisting-kernel-behavior.patch This patch was dropped because an alternative patch was merged ------------------------------------------------------ From: Tetsuo Handa Subject: add kernel config option for twisting kernel behavior. Existing kernel config options are defined based on "whether you want to enable this module/feature or not". And such granularity is sometimes too rough-grained for fuzzing tools which try to find bugs inside each module/feature. While syzkaller (one of fuzzing tools) is finding many bugs, sometimes syzkaller examines stupid operations. Some examples of such operations are: changing console loglevel which in turn makes it impossible to get kernel messages when a crash happens, freezing filesystems which in turn causes khungtaskd to needlessly complain, programmatically sending Ctrl-Alt-Del which in turn causes the system to needlessly reboot. Currently we prevent syzkaller from examining stupid operations by blacklisting syscall arguments and/or disabling whole functionality using existing kernel config options. But such approach is difficult to maintain and needlessly prevents fuzzers from testing kernel code. [1] We want fuzzers to test as much coverage as possible while we want fuzzers not to try stupid operations. To achieve this goal, we want cooperation from kernel side, and build-time branching (i.e. kernel config options) will be the simplest and the most reliable. Therefore, this patch introduces a kernel config option which allows selecting fine-grained kernel config options for twisting kernel's behavior. Each fine-grained kernel config option will be added by future patches. For ease of management, grouping kernel config options for allowing e.g. syzkaller to select all fine-grained kernel config options which e.g. syzkaller wants would be added by future patches. [1] https://lkml.kernel.org/r/CACT4Y+a6KExbggs4mg8pvoD554PcDqQNW4sM15X-tc=YONCzYw@mail.gmail.com Link: http://lkml.kernel.org/r/20200421131951.4948-1-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa Cc: Greg Kroah-Hartman Cc: Steven Rostedt Cc: Dmitry Vyukov Cc: Matthew Garrett Cc: Andi Kleen Cc: "Theodore Y . Ts'o" Cc: Alexander Viro Cc: Petr Mladek Cc: Sergey Senozhatsky Cc: Arnd Bergmann Cc: Jiri Slaby Cc: Peter Zijlstra Signed-off-by: Andrew Morton --- lib/Kconfig.debug | 2 ++ lib/Kconfig.twist | 13 +++++++++++++ 2 files changed, 15 insertions(+) --- a/lib/Kconfig.debug~add-kernel-config-option-for-twisting-kernel-behavior +++ a/lib/Kconfig.debug @@ -2287,4 +2287,6 @@ config HYPERV_TESTING endmenu # "Kernel Testing and Coverage" +source "lib/Kconfig.twist" + endmenu # Kernel hacking --- /dev/null +++ a/lib/Kconfig.twist @@ -0,0 +1,13 @@ +menuconfig TWIST_KERNEL_BEHAVIOR + bool "Twist kernel behavior" + help + Saying Y here allows modifying kernel behavior via kernel + config options which will become visible by selecting this + config option. Since these kernel config options are intended + for helping e.g. fuzz testing, behavior twisted by this kernel + option might be unstable. Userspace applications should not + count on this option being selected. + +if TWIST_KERNEL_BEHAVIOR + +endif # TWIST_KERNEL_BEHAVIOR _ Patches currently in -mm which might be from penguin-kernel@I-love.SAKURA.ne.jp are info-task-hung-in-generic_file_write_iter.patch info-task-hung-in-generic_file_write-fix.patch twist-allow-disabling-k_spec-function-in-drivers-tty-vt-keyboardc.patch twist-add-option-for-selecting-twist-options-for-syzkallers-testing.patch