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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 6A237C2D0E4 for ; Mon, 23 Nov 2020 12:23:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2153420728 for ; Mon, 23 Nov 2020 12:23:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hyr4r+Nd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729610AbgKWMXW (ORCPT ); Mon, 23 Nov 2020 07:23:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:60294 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729601AbgKWMXV (ORCPT ); Mon, 23 Nov 2020 07:23:21 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EC7CC2076E; Mon, 23 Nov 2020 12:23:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1606134200; bh=93VrMVYKxpRP0ORf3ecOd7y7hC7tY7W+PyTw58cxmMg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hyr4r+Nd42BISqzk7GwXv+u76nGbKohV9U8OmDC+IF/jZ5cpElQOSMRgEB+V1+ej0 J7wqw63YbahLu6o2KrRzVyQnAqHih0PoH9wvJLQJgO/LS3Bb2O1CVjAVjJ/KX3+2ad AjKaYAMay8BEG0mSyQ+jr80k/AG3gHUXMdHcz33w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Naresh Kamboju , Arnd Bergmann , Nishanth Menon , Mark Brown , Sasha Levin Subject: [PATCH 4.4 24/38] regulator: ti-abb: Fix array out of bound read access on the first transition Date: Mon, 23 Nov 2020 13:22:10 +0100 Message-Id: <20201123121805.463420839@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123121804.306030358@linuxfoundation.org> References: <20201123121804.306030358@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nishanth Menon [ Upstream commit 2ba546ebe0ce2af47833d8912ced9b4a579f13cb ] At the start of driver initialization, we do not know what bias setting the bootloader has configured the system for and we only know for certain the very first time we do a transition. However, since the initial value of the comparison index is -EINVAL, this negative value results in an array out of bound access on the very first transition. Since we don't know what the setting is, we just set the bias configuration as there is nothing to compare against. This prevents the array out of bound access. NOTE: Even though we could use a more relaxed check of "< 0" the only valid values(ignoring cosmic ray induced bitflips) are -EINVAL, 0+. Fixes: 40b1936efebd ("regulator: Introduce TI Adaptive Body Bias(ABB) on-chip LDO driver") Link: https://lore.kernel.org/linux-mm/CA+G9fYuk4imvhyCN7D7T6PMDH6oNp6HDCRiTUKMQ6QXXjBa4ag@mail.gmail.com/ Reported-by: Naresh Kamboju Reviewed-by: Arnd Bergmann Signed-off-by: Nishanth Menon Link: https://lore.kernel.org/r/20201118145009.10492-1-nm@ti.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/regulator/ti-abb-regulator.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/regulator/ti-abb-regulator.c b/drivers/regulator/ti-abb-regulator.c index 6d17357b3a248..5f5f63eb8c762 100644 --- a/drivers/regulator/ti-abb-regulator.c +++ b/drivers/regulator/ti-abb-regulator.c @@ -342,8 +342,17 @@ static int ti_abb_set_voltage_sel(struct regulator_dev *rdev, unsigned sel) return ret; } - /* If data is exactly the same, then just update index, no change */ info = &abb->info[sel]; + /* + * When Linux kernel is starting up, we are'nt sure of the + * Bias configuration that bootloader has configured. + * So, we get to know the actual setting the first time + * we are asked to transition. + */ + if (abb->current_info_idx == -EINVAL) + goto just_set_abb; + + /* If data is exactly the same, then just update index, no change */ oinfo = &abb->info[abb->current_info_idx]; if (!memcmp(info, oinfo, sizeof(*info))) { dev_dbg(dev, "%s: Same data new idx=%d, old idx=%d\n", __func__, @@ -351,6 +360,7 @@ static int ti_abb_set_voltage_sel(struct regulator_dev *rdev, unsigned sel) goto out; } +just_set_abb: ret = ti_abb_set_opp(rdev, abb, info); out: -- 2.27.0