From: Arnd Bergmann <arnd@kernel.org>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Walter Wu <walter-zh.wu@mediatek.com>,
wsd_upstream <wsd_upstream@mediatek.com>,
Arnd Bergmann <arnd@arndb.de>,
"moderated list:ARM/Mediatek SoC..."
<linux-mediatek@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>,
Linux Memory Management List <linux-mm@kvack.org>,
Alexander Potapenko <glider@google.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nathan Chancellor <natechancellor@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH v3] kasan: remove redundant config option
Date: Fri, 8 Jan 2021 21:30:53 +0100 [thread overview]
Message-ID: <CAK8P3a3FakV-Y9xkoy_fpYKBNkMvcO7DPOQC8R7ku7yPcgDw3g@mail.gmail.com> (raw)
In-Reply-To: <CAAeHK+wW3bTCvk=6v_vDQFYLC6=3kunmprXA-P=tWyXCTMZjhQ@mail.gmail.com>
On Fri, Jan 8, 2021 at 7:56 PM Andrey Konovalov <andreyknvl@google.com> wrote:
> On Fri, Jan 8, 2021 at 5:09 AM Walter Wu <walter-zh.wu@mediatek.com> wrote:
> > @@ -2,6 +2,12 @@
> > CFLAGS_KASAN_NOSANITIZE := -fno-builtin
> > KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
> >
> > +ifdef CONFIG_KASAN_STACK
> > + stack_enable := 1
> > +else
> > + stack_enable := 0
> > +endif
> > +
>
> AFAIR, Arnd wanted to avoid having KASAN_STACK to be enabled by
> default when compiling with Clang, since Clang instrumentation leads
> to very large kernel stacks, which, in turn, lead to compile-time
> warnings. What I don't remember is why there are two configs.
>
> Arnd, is that correct? What was the reason behind having two configs?
I think I just considered it cleaner than defining the extra variable in the
Makefile at the time, as this was the only place that referenced
CONFIG_KASAN_STACK.
The '#if CONFIG_KASAN_STACK' (rather than #ifdef) that got added
later do make my version more confusing though, so I agree that
Walter's second patch improves it.
Acked-by: Arnd Bergmann <arnd@arndb.de>
On a related note: do you have any hope that clang will ever fix
https://bugs.llvm.org/show_bug.cgi?id=38809 and KASAN_STACK
can be enabled by default on clang without risking stack
overflows?
Arnd
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next prev parent reply other threads:[~2021-01-08 20:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 4:09 [PATCH v3] kasan: remove redundant config option Walter Wu
2021-01-08 4:16 ` Nathan Chancellor
2021-01-08 18:56 ` Andrey Konovalov
2021-01-08 20:30 ` Arnd Bergmann [this message]
2021-01-11 17:40 ` Andrey Konovalov
2021-01-11 17:49 ` Andrey Konovalov
2021-01-11 18:59 ` Nathan Chancellor
2021-01-11 19:03 ` Andrey Konovalov
2021-01-11 19:11 ` Nathan Chancellor
2021-01-11 19:30 ` Andrey Konovalov
2021-01-11 19:30 ` Andrey Konovalov
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