From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50C7CC282DA for ; Fri, 19 Apr 2019 18:22:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23175222AF for ; Fri, 19 Apr 2019 18:22:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="2JQf30n2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727799AbfDSSWb (ORCPT ); Fri, 19 Apr 2019 14:22:31 -0400 Received: from condef-10.nifty.com ([202.248.20.75]:44887 "EHLO condef-10.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727344AbfDSSW2 (ORCPT ); Fri, 19 Apr 2019 14:22:28 -0400 Received: from conuserg-08.nifty.com ([10.126.8.71])by condef-10.nifty.com with ESMTP id x3J9nQOg020059; Fri, 19 Apr 2019 18:49:26 +0900 Received: from localhost.localdomain (p14092-ipngnfx01kyoto.kyoto.ocn.ne.jp [153.142.97.92]) (authenticated) by conuserg-08.nifty.com with ESMTP id x3J9mDiM012304; Fri, 19 Apr 2019 18:48:15 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com x3J9mDiM012304 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1555667296; bh=xEQiTaRJoMiIIoSSR5uW02FG6OV+z3ajZxuyDMzswK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2JQf30n281jQB4d2J0PFa1uofVewZCgz9BKrQlNEnXrgFMBLbR2Zq1r6w+iBaLG45 t3nsjO2yy9K2rayA6kAG7W5QOZXT/QC/pn2nbYfF3OTOTfF8RmCuBd5yJ5z4STfAVR S50CNHJXKGoZKrDOh8HkCZk629LOHn6U1lbZhC7JMhAyR3/Tr/rg3GcrCj9JDWjHAO UiGSppMnUWU7gB7Bziv+abekGW5t79hjFO9/SOc6KfN1rVoLYaqIJni87B3Xd6Wk7W H2/rg3c+1nge1l4Y9lbsm/7RvW65UIRkVG9T0d8qJA6UMAluoWZAQ17RYMK74wx8Rp ffTOmV/uhafAw== X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: Andrew Morton , linux-arch Cc: linux-s390@vger.kernel.org, Heiko Carstens , Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Christophe Leroy , Masahiro Yamada Subject: [PATCH v2 01/11] ARM: prevent tracing IPI_CPU_BACKTRACE Date: Fri, 19 Apr 2019 18:47:44 +0900 Message-Id: <20190419094754.24667-2-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190419094754.24667-1-yamada.masahiro@socionext.com> References: <20190419094754.24667-1-yamada.masahiro@socionext.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnd Bergmann When function tracing for IPIs is enabled, we get a warning for an overflow of the ipi_types array with the IPI_CPU_BACKTRACE type as triggered by raise_nmi(): arch/arm/kernel/smp.c: In function 'raise_nmi': arch/arm/kernel/smp.c:489:2: error: array subscript is above array bounds [-Werror=array-bounds] trace_ipi_raise(target, ipi_types[ipinr]); This is a correct warning as we actually overflow the array here. This patch raise_nmi() to call __smp_cross_call() instead of smp_cross_call(), to avoid calling into ftrace. For clarification, I'm also adding a two new code comments describing how this one is special. The warning appears to have shown up after patch e7273ff49acf ("ARM: 8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI"), which changed the number assignment from '15' to '8', but as far as I can tell has existed since the IPI tracepoints were first introduced. If we decide to backport this patch to stable kernels, we probably need to backport e7273ff49acf as well. Fixes: e7273ff49acf ("ARM: 8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI") Fixes: 365ec7b17327 ("ARM: add IPI tracepoints") # v3.17 Signed-off-by: Arnd Bergmann [yamada.masahiro@socionext.com: rebase on v5.0-rc1] Signed-off-by: Masahiro Yamada --- This is a long-standing issue, and Arnd posted this patch two years ago: http://lists.infradead.org/pipermail/linux-arm-kernel/2016-February/409393.html It is no longer applied, so I rebased it on top of the latest kernel. Changes in v2: None arch/arm/include/asm/hardirq.h | 1 + arch/arm/kernel/smp.c | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm/include/asm/hardirq.h b/arch/arm/include/asm/hardirq.h index cba23eaa6072..7a88f160b1fb 100644 --- a/arch/arm/include/asm/hardirq.h +++ b/arch/arm/include/asm/hardirq.h @@ -6,6 +6,7 @@ #include #include +/* number of IPIS _not_ including IPI_CPU_BACKTRACE */ #define NR_IPI 7 typedef struct { diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index facd4240ca02..c93fe0f256de 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -70,6 +70,10 @@ enum ipi_msg_type { IPI_CPU_STOP, IPI_IRQ_WORK, IPI_COMPLETION, + /* + * CPU_BACKTRACE is special and not included in NR_IPI + * or tracable with trace_ipi_* + */ IPI_CPU_BACKTRACE, /* * SGI8-15 can be reserved by secure firmware, and thus may @@ -797,7 +801,7 @@ core_initcall(register_cpufreq_notifier); static void raise_nmi(cpumask_t *mask) { - smp_cross_call(mask, IPI_CPU_BACKTRACE); + __smp_cross_call(mask, IPI_CPU_BACKTRACE); } void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) -- 2.17.1