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Fri, 08 Jan 2021 12:31:09 -0800 (PST) MIME-Version: 1.0 References: <20210108040940.1138-1-walter-zh.wu@mediatek.com> In-Reply-To: From: Arnd Bergmann Date: Fri, 8 Jan 2021 21:30:53 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3] kasan: remove redundant config option To: Andrey Konovalov X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210108_153111_455247_2E1936A8 X-CRM114-Status: GOOD ( 13.66 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Walter Wu , wsd_upstream , Arnd Bergmann , "moderated list:ARM/Mediatek SoC..." , LKML , kasan-dev , Linux Memory Management List , Alexander Potapenko , Linux ARM , Andrey Ryabinin , Andrew Morton , Nathan Chancellor , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jan 8, 2021 at 7:56 PM Andrey Konovalov wrote: > On Fri, Jan 8, 2021 at 5:09 AM Walter Wu 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 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel