Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756357AbbGPBwd (ORCPT ); Wed, 15 Jul 2015 21:52:33 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:55747 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754651AbbGPBKx (ORCPT ); Wed, 15 Jul 2015 21:10:53 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Maxime Coquelin , Mark Brown , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 118/251] regmap: Fix possible shift overflow in regmap_field_init() Date: Wed, 15 Jul 2015 18:07:19 -0700 Message-Id: <1437008972-9140-119-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1437008972-9140-1-git-send-email-kamal@canonical.com> References: <1437008972-9140-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1810 Lines: 50 3.19.8-ckt4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Maxime Coquelin commit 921cc29473a0d7c109105c1876ddb432f4a4be7d upstream. The way the mask is generated in regmap_field_init() is wrong. Indeed, a field initialized with msb = 31 and lsb = 0 provokes a shift overflow while calculating the mask field. On some 32 bits architectures, such as x86, the generated mask is 0, instead of the expected 0xffffffff. This patch uses GENMASK() to fix the problem, as this macro is already safe regarding shift overflow. Signed-off-by: Maxime Coquelin Signed-off-by: Mark Brown Signed-off-by: Kamal Mostafa --- drivers/base/regmap/regmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index a434df6..b389c1d 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -944,11 +944,10 @@ EXPORT_SYMBOL_GPL(devm_regmap_init); static void regmap_field_init(struct regmap_field *rm_field, struct regmap *regmap, struct reg_field reg_field) { - int field_bits = reg_field.msb - reg_field.lsb + 1; rm_field->regmap = regmap; rm_field->reg = reg_field.reg; rm_field->shift = reg_field.lsb; - rm_field->mask = ((BIT(field_bits) - 1) << reg_field.lsb); + rm_field->mask = GENMASK(reg_field.msb, reg_field.lsb); rm_field->id_size = reg_field.id_size; rm_field->id_offset = reg_field.id_offset; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/