From patchwork Fri Feb 22 22:29:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 10827099 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CDF596C2 for ; Fri, 22 Feb 2019 22:30:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B721F315B0 for ; Fri, 22 Feb 2019 22:30:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A40D0315BE; Fri, 22 Feb 2019 22:30:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DA2CA315B0 for ; Fri, 22 Feb 2019 22:30:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725878AbfBVWaK (ORCPT ); Fri, 22 Feb 2019 17:30:10 -0500 Received: from mout.kundenserver.de ([212.227.126.187]:59847 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725980AbfBVWaJ (ORCPT ); Fri, 22 Feb 2019 17:30:09 -0500 Received: from wuerfel.lan ([109.192.41.194]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.129]) with ESMTPA (Nemesis) id 1MF39M-1gmGhn2OWe-00FSNQ; Fri, 22 Feb 2019 23:29:55 +0100 From: Arnd Bergmann To: Andrey Ryabinin , Masahiro Yamada , Michal Marek , Andrew Morton Cc: Arnd Bergmann , Dmitry Vyukov , Nick Desaulniers , Mark Brown , Qian Cai , Kostya Serebryany , Andrey Konovalov , Alexander Potapenko , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-kbuild@vger.kernel.org Subject: [PATCH] [v2] kasan: turn off asan-stack for clang-8 and earlier Date: Fri, 22 Feb 2019 23:29:10 +0100 Message-Id: <20190222222950.3997333-1-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 X-Provags-ID: V03:K1:EQsDhKNCDlCKmr3wDthNBS4aj4njVj4uZe/w3vijzQ2DqPrzKT/ kWnaIjf6AUMXb7nqAjREyOctiQvsWUG3AP9vfcDiRYW95SVCWxOlL9E8ZEy7NAGKT4RtWQN S/+zebh6gqCp1r2MhEBgelOIGivJyDbXADOauTTry5xinRJ8Uzva3lUcQKg8Nu6IpScXShY bDtckkFQVAyfVywW+zGkA== X-UI-Out-Filterresults: notjunk:1;V03:K0:5jZ76+ZLx90=:rKd3DFhmwG/miABR8B0Snb 6AXc6t7bJg0Ba/ZtpMp/xium1QJ6yUGZ89z0b2Jesmsz/camMrX4qUHw9IOLe1Y6kYgse6gTs Qfn9CXIomWxwQJSuzfvRd+58X8ek9oLTIMN9sgH9+YXB63VrNrweBC4uSRwiPoORd7X5jSEg4 KGuubtOFPwM2hZGWDB3vL9gTRZdS2hmgl9eGELR3fyR4aD6zvwESB5XC4SWb/N0yM10KCNnZc 7pEJKPPC5g4A4mJSSaa2RnxWLbr63ugO5fDFZwDAaQmkNh8WVmzLnS/3Yuqs9jJabjx4so+uN RgDhBQSrHIk9b+NeukHdISSb/1OHrs1gj0ogMREZ4ClZZ86GyIj2bzClE/r4zzDAiU30XyDyw D0aq4GxUW627xKQe8/OfEpKgJRS3bpXKKmX2JaL88GCvXYb/+SzrpJ9qlOIeXIWSt5wUKSdIL t0txIwwqIcoq8aeUCI/e4ajXAuMxqXm25wMsWm16YMLV4fYxliV9djeeD78n8wcGq8mi3AGpO dP3ij3YzZ8AwKf1iJZGzG5qP/dwu2DzpOMStknl+1lg3nMnTmFfLFdL8VD4V7g3sCVuw2lVTA 56u/cLYqFTRLhT+Y+mJSKznS+OHN45d+z02TuvVeo7we76rdDKv/gw1aK99ycZmedqcIz4bfn xKQNq2Lu215q5I7ZtuEjWDlDW5y9R+aBvivPA5v1cbxfP4HhgrywtjCGGjom+bXxjb0iTY/su SeIbVIlsKmYiLBYGN4UIJNb7j6hhQjECxJxeoQ== Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Building an arm64 allmodconfig kernel with clang results in over 140 warnings about overly large stack frames, the worst ones being: drivers/gpu/drm/panel/panel-sitronix-st7789v.c:196:12: error: stack frame size of 20224 bytes in function 'st7789v_prepare' drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td028ttec1.c:196:12: error: stack frame size of 13120 bytes in function 'td028ttec1_panel_enable' drivers/usb/host/max3421-hcd.c:1395:1: error: stack frame size of 10048 bytes in function 'max3421_spi_thread' drivers/net/wan/slic_ds26522.c:209:12: error: stack frame size of 9664 bytes in function 'slic_ds26522_probe' drivers/crypto/ccp/ccp-ops.c:2434:5: error: stack frame size of 8832 bytes in function 'ccp_run_cmd' drivers/media/dvb-frontends/stv0367.c:1005:12: error: stack frame size of 7840 bytes in function 'stv0367ter_algo' None of these happen with gcc today, and almost all of these are the result of a single known issue in llvm. Hopefully it will eventually get fixed with the clang-9 release. In the meantime, the best idea I have is to turn off asan-stack for clang-8 and earlier, so we can produce a kernel that is safe to run. I have posted three patches that address the frame overflow warnings that are not addressed by turning off asan-stack, so in combination with this change, we get much closer to a clean allmodconfig build, which in turn is necessary to do meaningful build regression testing. It is still possible to turn on the CONFIG_ASAN_STACK option on all versions of clang, and it's always enabled for gcc, but when CONFIG_COMPILE_TEST is set, the option remains invisible, so allmodconfig and randconfig builds (which are normally done with a forced CONFIG_COMPILE_TEST) will still result in a mostly clean build. Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Nick Desaulniers Cc: Mark Brown Cc: Qian Cai Cc: Kostya Serebryany Cc: Andrey Konovalov Link: https://bugs.llvm.org/show_bug.cgi?id=38809 Signed-off-by: Arnd Bergmann Reviewed-by: Qian Cai Reviewed-by: Mark Brown Acked-by: Andrey Ryabinin --- Changes in v2: - allow CONFIG_KASAN_STACK to be manually enabled/disabled on all clang versions, just make the default version specific, and ensure that it's turned off for allmodconfig build testing --- lib/Kconfig.kasan | 22 ++++++++++++++++++++++ scripts/Makefile.kasan | 2 +- 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index 67d7d1309c52..9950b660e62d 100644 --- a/lib/Kconfig.kasan +++ b/lib/Kconfig.kasan @@ -103,6 +103,28 @@ config KASAN_INLINE endchoice +config KASAN_STACK_ENABLE + bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST + default !(CLANG_VERSION < 90000) + depends on KASAN + help + The LLVM stack address sanitizer has a know problem that + causes excessive stack usage in a lot of functions, see + https://bugs.llvm.org/show_bug.cgi?id=38809 + Disabling asan-stack makes it safe to run kernels build + with clang-8 with KASAN enabled, though it loses some of + the functionality. + This feature is always disabled when compile-testing with clang-8 + or earlier to avoid cluttering the output in stack overflow + warnings, but clang-8 users can still enable it for builds without + CONFIG_COMPILE_TEST. On gcc and later clang versions it is + assumed to always be safe to use and enabled by default. + +config KASAN_STACK + int + default 1 if KASAN_STACK_ENABLE || CC_IS_GCC + default 0 + config KASAN_S390_4_LEVEL_PAGING bool "KASan: use 4-level paging" depends on KASAN && S390 diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index f1fb8e502657..6410bd22fe38 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -26,7 +26,7 @@ else CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \ $(call cc-param,asan-globals=1) \ $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \ - $(call cc-param,asan-stack=1) \ + $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \ $(call cc-param,asan-instrument-allocas=1) endif