From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 14 Mar 2016 18:52:24 +0100 (CET) Received: from mail.linuxfoundation.org ([140.211.169.12]:50958 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27008987AbcCNRwE4VIIi (ORCPT ); Mon, 14 Mar 2016 18:52:04 +0100 Received: from localhost (c-50-170-35-168.hsd1.wa.comcast.net [50.170.35.168]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id D855CD0B; Mon, 14 Mar 2016 17:51:58 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Hogan , Paul Burton , linux-mips@linux-mips.org, Ralf Baechle Subject: [PATCH 4.4 47/50] MIPS: smp.c: Fix uninitialised temp_foreign_map Date: Mon, 14 Mar 2016 10:51:05 -0700 Message-Id: <20160314175020.053660127@linuxfoundation.org> X-Mailer: git-send-email 2.7.2 In-Reply-To: <20160314175013.403628835@linuxfoundation.org> References: <20160314175013.403628835@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 52585 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: gregkh@linuxfoundation.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Hogan commit d825c06bfe8b885b797f917ad47365d0e9c21fbb upstream. When calculate_cpu_foreign_map() recalculates the cpu_foreign_map cpumask it uses the local variable temp_foreign_map without initialising it to zero. Since the calculation only ever sets bits in this cpumask any existing bits at that memory location will remain set and find their way into cpu_foreign_map too. This could potentially lead to cache operations suboptimally doing smp calls to multiple VPEs in the same core, even though the VPEs share primary caches. Therefore initialise temp_foreign_map using cpumask_clear() before use. Fixes: cccf34e9411c ("MIPS: c-r4k: Fix cache flushing for MT cores") Signed-off-by: James Hogan Cc: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12759/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/smp.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -121,6 +121,7 @@ static inline void calculate_cpu_foreign cpumask_t temp_foreign_map; /* Re-calculate the mask */ + cpumask_clear(&temp_foreign_map); for_each_online_cpu(i) { core_present = 0; for_each_cpu(k, &temp_foreign_map)