Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Sender: Guenter Roeck <groeck7@gmail.com>
Date:   Tue, 13 Dec 2022 05:11:40 -0800
From:   Guenter Roeck <linux@roeck-us.net>
To:     "Sudip Mukherjee (Codethink)" <sudipm.mukherjee@gmail.com>
Cc:     Vlastimil Babka <vbabka@suse.cz>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: mainline build failure due to e240e53ae0ab ("mm, slub: add
 CONFIG_SLUB_TINY")
Message-ID: <20221213131140.GA3622636@roeck-us.net>
References: <Y5hTTGf/RA2kpqOF@debian>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Y5hTTGf/RA2kpqOF@debian>
Precedence: bulk

On Tue, Dec 13, 2022 at 10:26:20AM +0000, Sudip Mukherjee (Codethink) wrote:
> Hi All,
> 
> The latest mainline kernel branch fails to build xtensa allmodconfig 
> with gcc-11 with the error:
> 
> kernel/kcsan/kcsan_test.c: In function '__report_matches':
> kernel/kcsan/kcsan_test.c:257:1: error: the frame size of 1680 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]
>   257 | }
>       | ^
> 
> git bisect pointed to e240e53ae0ab ("mm, slub: add CONFIG_SLUB_TINY")
> 

In part that is because above commit changes Kconfig dependencies such
that xtensa:allmodconfig actually tries to build kernel/kcsan/kcsan_test.o.
In v6.1, CONFIG_KCSAN_KUNIT_TEST is not enabled for xtensa:allmodconfig.

Downside of the way SLUB_TINY is defined is that it is enabled for all
allmodconfig / allyesconfig builds, which then disables building a lot
of the more sophisticated memory allocation options.

Guenter