From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934989AbcKVWzK (ORCPT ); Tue, 22 Nov 2016 17:55:10 -0500 Received: from mout.kundenserver.de ([212.227.17.13]:65259 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933931AbcKVWzJ (ORCPT ); Tue, 22 Nov 2016 17:55:09 -0500 From: Arnd Bergmann To: Andrey Ryabinin Cc: Arnd Bergmann , =?UTF-8?q?Martin=20Li=C5=A1ka?= , Andrey Ryabinin , stable@vger.kernel.org, Michal Marek , Alexander Potapenko , Dmitry Vyukov , linux-kbuild@vger.kernel.org, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org Subject: [PATCH] kasan: turn off -fsanitize-address-use-after-scope for now Date: Tue, 22 Nov 2016 23:54:06 +0100 Message-Id: <20161122225424.3739294-1-arnd@arndb.de> X-Mailer: git-send-email 2.9.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K0:wP8kWKPxQVPS9w8C2YPPzBQ8W6Yn0cUK8qE9MfO7Ffvx1jUBc6D xpgrMEFxkBsCfiFJXqj0H2iyXA+ZGllx3rHL+IRoH661ml2LNQScAosKg2VsMZChSSZBqSu lVnp7w8dBR3uEWpOHDYdGwnnTG3u/fy1Hb9YPYerpp9JfjZa2vJ3uuQdvE4LWw5+L3ME1iW qo5Ws+s9pf5GWo4Q5XBGw== X-UI-Out-Filterresults: notjunk:1;V01:K0:P5T9AL4maDo=:D3bev7d8jxDbs7eGmdF5p5 ixUian/f59Tx+BeaqgnYs+k90AB3buTVIARfh38AXzWvx8OQdkxkoDXIX7yzIUxG7DsTG3gLT sOWFfIwEVdjiN/zGeqR/B1JNwvd+j9joGN8jmf7gqBCDoM7Qa/2bgYDJI0bh0r07PMLOVQXNk sQyXFJYnhID1hHB2auXiPVm41PCsi0pQX0zlQpDGEORk/BnSKjrSyyiHi1UVTi8W2JKbiSQz5 JFLWrgOR1z02KGht21DMj87iZHF1Vd/mnp8GSoreWxNVhXewBgK8QpErPKOUVa07qRjcNGEY8 CNAVxUi1uGCVBzPJSBra48oXpckwnPBLi2QMuHjYd7Z4DKVjFgnctC6/Tf4neQ3jR0NHByDOg i5vNbD1LruiZuYp0wQPOP7IxJSPQZSPPywgP3H1oW5SUNDo1dzdQ9xG9Ls3hPunUEC+X1r0rY q2pUIvY/OpoA/1kpKm/DZk6zgZOXFp6dlX/KaHTArKyhxqg6WXswYj1RKUA6h/Dv3pSNDKqfZ tUHgEATvFF/dL+Yy7OIzgM3XNKutkoQqy2nCtoAzPjwNnREckhH3P50wm4zNmc4H49Yr6Uz1v sybeBJuRvnqfe+Sk1NOMTOOfmfM+b/J4Zaidnb+mgQBv7oUxhAjgvfJBCAMDMUChxZiC57STr CGEbqWEZeN8EhRmep283TeuF4gZijQLSpZpRyo82fZczQSJPL14RRXA6D8HR+bUqvVTM6vzwg H7QJBGTB1rnUGXyM Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the upcoming gcc-7 release, the -fsanitize=kernel-address option implies -fsanitize-address-use-after-scope, which relies on the definition of two global functions, causing many link errors if they are not defined, e.g: arch/x86/built-in.o: In function `x86_pmu_handle_irq': (.text+0x88e6): undefined reference to `__asan_unpoison_stack_memory' arch/x86/built-in.o: In function `x86_pmu_handle_irq': (.text+0x8ad7): undefined reference to `__asan_poison_stack_memory' kernel/built-in.o: In function `perf_tp_event': (.text+0x225472): undefined reference to `__asan_unpoison_stack_memory' kernel/built-in.o: In function `perf_tp_event': (.text+0x22583a): undefined reference to `__asan_unpoison_stack_memory' kernel/built-in.o: In function `perf_tp_event': (.text+0x2258ae): undefined reference to `__asan_poison_stack_memory' kernel/built-in.o: In function `perf_event_aux_event': I think we really want to define those two functions so we can make use of a helpful feature, but as I have no idea what they are supposed to do, I'd suggest to turn the option off on existing kernels to allow building with gcc-7 and kasan. For some reason, the problem showed up in only a few randconfig builds, but it is easy to reproduce using an x86-64 tinyconfig build with CONFIG_KASAN=y. If we decide to take this approach, we probably want to do the same change on all stable kernels that support KASAN, i.e. v4.0 or higher. Link: https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=241896 Cc: Martin Liška Cc: Andrey Ryabinin Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann --- scripts/Makefile.kasan | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index 37323b0df374..0e68fef09f76 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -29,3 +29,5 @@ else endif endif endif + +CFLAGS_KASAN += $(call cc-option, -fno-sanitize-address-use-after-scope) -- 2.9.0