Re: [PATCH v1 03/16] khwasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_HW

From: Andrey Konovalov <andreyknvl@google.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "Alexander Potapenko" <glider@google.com>,
	"Dmitry Vyukov" <dvyukov@google.com>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Will Deacon" <will.deacon@arm.com>,
	"Christopher Li" <sparse@chrisli.org>,
	"Christoph Lameter" <cl@linux.com>,
	"Pekka Enberg" <penberg@kernel.org>,
	"David Rientjes" <rientjes@google.com>,
	"Joonsoo Kim" <iamjoonsoo.kim@lge.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Michal Marek" <michal.lkml@markovi.net>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Nick Desaulniers" <ndesaulniers@google.com>,
	"Yury Norov" <ynorov@caviumnetworks.com>,
	"Marc Zyngier" <marc.zyngier@arm.com>,
	"Kristina Martsenko" <kristina.martsenko@arm.com>,
	"Suzuki K Poulose" <suzuki.poulose@arm.com>,
	"Punit Agrawal" <punit.agrawal@arm.com>,
	"Dave Martin" <dave.martin@arm.com>,
	"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
	"James Morse" <james.morse@arm.com>,
	"Michael Weiser" <michael.weiser@gmx.de>,
	"Julien Thierry" <julien.thierry@arm.com>,
	"Tyler Baicar" <tbaicar@codeaurora.org>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@kernel.org>,
	"Kees Cook" <keescook@chromium.org>,
	"Sandipan Das" <sandipan@linux.vnet.ibm.com>,
	"David Woodhouse" <dwmw@amazon.co.uk>,
	"Paul Lawrence" <paullawrence@google.com>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"Josh Poimboeuf" <jpoimboe@redhat.com>,
	"Geert Uytterhoeven" <geert@linux-m68k.org>,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Michal Hocko" <mhocko@suse.com>, "Jan Kara" <jack@suse.cz>,
	"Ross Zwisler" <ross.zwisler@linux.intel.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Matthew Wilcox" <mawilcox@microsoft.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	"Souptick Joarder" <jrdr.linux@gmail.com>,
	"Hugh Dickins" <hughd@google.com>,
	"Davidlohr Bueso" <dave@stgolabs.net>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Philippe Ombredanne" <pombredanne@nexb.com>,
	"Kate Stewart" <kstewart@linuxfoundation.org>,
	"Laura Abbott" <labbott@redhat.com>,
	"Boris Brezillon" <boris.brezillon@bootlin.com>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Pintu Agarwal" <pintu.ping@gmail.com>,
	"Doug Berger" <opendmb@gmail.com>,
	"Anshuman Khandual" <khandual@linux.vnet.ibm.com>,
	"Mike Rapoport" <rppt@linux.vnet.ibm.com>,
	"Mel Gorman" <mgorman@suse.de>,
	"Pavel Tatashin" <pasha.tatashin@oracle.com>,
	"Tetsuo Handa" <penguin-kernel@i-love.sakura.ne.jp>,
	kasan-dev <kasan-dev@googlegroups.com>,
	linux-doc@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
	linux-sparse@vger.kernel.org,
	"Linux Memory Management List" <linux-mm@kvack.org>,
	"Linux Kbuild mailing list" <linux-kbuild@vger.kernel.org>,
	"Kostya Serebryany" <kcc@google.com>,
	"Evgeniy Stepanov" <eugenis@google.com>,
	"Lee Smith" <Lee.Smith@arm.com>,
	"Ramana Radhakrishnan" <Ramana.Radhakrishnan@arm.com>,
	"Jacob Bramley" <Jacob.Bramley@arm.com>,
	"Ruben Ayrapetyan" <Ruben.Ayrapetyan@arm.com>,
	"Kees Cook" <keescook@google.com>, "Jann Horn" <jannh@google.com>,
	"Mark Brand" <markbrand@google.com>,
	"Chintan Pandya" <cpandya@codeaurora.org>
Subject: Re: [PATCH v1 03/16] khwasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_HW
Date: Thu, 24 May 2018 18:52:22 +0200	[thread overview]
Message-ID: <CAAeHK+wZy+XpkHpvcGL9e+g84mjTUK0d+T1V2Ljmwd_c+qiAog@mail.gmail.com> (raw)
In-Reply-To: <CAAeHK+yW_kOrL58fkvmJ=84RXzijFTHCd85Ahp3Bj1E79QeziA@mail.gmail.com>

On Tue, May 22, 2018 at 4:25 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
> On Mon, May 14, 2018 at 6:57 PM, Andrey Ryabinin
> <aryabinin@virtuozzo.com> wrote:
>>
>>
>> On 05/08/2018 08:20 PM, Andrey Konovalov wrote:
>>
>>> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
>>> index 69552a39951d..47023daf5606 100644
>>> --- a/scripts/Makefile.kasan
>>> +++ b/scripts/Makefile.kasan
>>> @@ -1,5 +1,5 @@
>>>  # SPDX-License-Identifier: GPL-2.0
>>> -ifdef CONFIG_KASAN
>>> +ifdef CONFIG_KASAN_GENERIC
>>>  ifdef CONFIG_KASAN_INLINE
>>>       call_threshold := 10000
>>>  else
>>> @@ -45,3 +45,28 @@ endif
>>>  CFLAGS_KASAN_NOSANITIZE := -fno-builtin
>>>
>>>  endif
>>> +
>>> +ifdef CONFIG_KASAN_HW
>>> +
>>> +ifdef CONFIG_KASAN_INLINE
>>> +    instrumentation_flags := -mllvm -hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
>>> +else
>>> +    instrumentation_flags := -mllvm -hwasan-instrument-with-calls=1
>>> +endif
>>> +
>>> +CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-hwaddress
>>> +
>>> +ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
>>> +    ifneq ($(CONFIG_COMPILE_TEST),y)
>>> +        $(warning Cannot use CONFIG_KASAN_HW: \
>>> +            -fsanitize=hwaddress is not supported by compiler)
>>> +    endif
>>> +else
>>> +    CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-hwaddress \
>>> +        -mllvm -hwasan-instrument-stack=0 \
>>> +        $(instrumentation_flags))
>>> +endif
>>
>> So this code does the following:
>>  1) Warn if compiler doesn't support -fsanitize=kernel-hwaddress
>>  2) Compile the kernel with all necessary set of the '-fsanitize=kernel-hwaddress -mllvm -hwasan-*' flags if compiler supports all of them.
>>  3) Compile the kernel with empty CFLAGS_KASAN without a warning if compiler supports 'fsanitize=kernel-hwaddress',
>>      but doesn't support the rest '-mllvm -hwasan-*' flags.
>>
>> The last one is just nonsense.
>
> Should I remove "call cc-option" to fix this?

Nevermind, will fix in v2.

>
>>
>>
>>> +
>>> +CFLAGS_KASAN_NOSANITIZE := -fno-builtin
>>> +
>>
>> Does it really has to declared twice?
>
> Will fix in v2.