From patchwork Fri Jan 24 09:29:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 11350091 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DF7B66C1 for ; Fri, 24 Jan 2020 11:21:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEACC21569 for ; Fri, 24 Jan 2020 11:21:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579864863; bh=RdrUScjQ4MYppyBddLWVOttt3KTsGUskbpY4fRW3W0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=I7iH/Fv+PeZQKxcPFK7uwhpP2LXc4u4Usx0pwb+xkJj+rzXDP10+krh3m31fQxSXi Wn53XtED5r7PXxNFcLs8C+Uq+seA8BlEXYHk1Fw42iHj4cVi18Xs04wPBNAN6uITR3 1AheVh1zS84WkhVHxMG18y8vObQcMjvspj169SVE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390801AbgAXLVC (ORCPT ); Fri, 24 Jan 2020 06:21:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:58938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390993AbgAXLVB (ORCPT ); Fri, 24 Jan 2020 06:21:01 -0500 Received: from localhost (ip-213-127-102-57.ip.prioritytelecom.net [213.127.102.57]) (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 4AEFF214AF; Fri, 24 Jan 2020 11:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579864860; bh=RdrUScjQ4MYppyBddLWVOttt3KTsGUskbpY4fRW3W0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ErrqAKPG5UiNC24LHbED9qiVU5lqa9JhdzognUPA3B2yXeYHwN8qFKKaGVRAOwTF7 F9Fo2WOKWabXdXm5a30IVxZTXJ2zSdPXAEcLymt7ugbGGb544fpAUcRmmCmw6L8N/M CvkwgrGFO84yIQ8tmFoCxdZyEc/vxZ9Zc6SpnXzw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Robert Richter , Borislav Petkov , "linux-edac@vger.kernel.org" , James Morse , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 4.19 374/639] EDAC/mc: Fix edac_mc_find() in case no device is found Date: Fri, 24 Jan 2020 10:29:04 +0100 Message-Id: <20200124093133.875709390@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200124093047.008739095@linuxfoundation.org> References: <20200124093047.008739095@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-edac-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org From: Robert Richter [ Upstream commit 29a0c843973bc385918158c6976e4dbe891df969 ] The function should return NULL in case no device is found, but it always returns the last checked mc device from the list even if the index did not match. Fix that. I did some analysis why this did not raise any issues for about 3 years and the reason is that edac_mc_find() is mostly used to search for existing devices. Thus, the bug is not triggered. [ bp: Drop the if (mci->mc_idx > idx) test in favor of readability. ] Fixes: c73e8833bec5 ("EDAC, mc: Fix locking around mc_devices list") Signed-off-by: Robert Richter Signed-off-by: Borislav Petkov Cc: "linux-edac@vger.kernel.org" Cc: James Morse Cc: Mauro Carvalho Chehab Link: https://lkml.kernel.org/r/20190514104838.15065-1-rrichter@marvell.com Signed-off-by: Sasha Levin --- drivers/edac/edac_mc.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c index f59511bd99261..fd440b35d76ed 100644 --- a/drivers/edac/edac_mc.c +++ b/drivers/edac/edac_mc.c @@ -681,22 +681,18 @@ static int del_mc_from_global_list(struct mem_ctl_info *mci) struct mem_ctl_info *edac_mc_find(int idx) { - struct mem_ctl_info *mci = NULL; + struct mem_ctl_info *mci; struct list_head *item; mutex_lock(&mem_ctls_mutex); list_for_each(item, &mc_devices) { mci = list_entry(item, struct mem_ctl_info, link); - - if (mci->mc_idx >= idx) { - if (mci->mc_idx == idx) { - goto unlock; - } - break; - } + if (mci->mc_idx == idx) + goto unlock; } + mci = NULL; unlock: mutex_unlock(&mem_ctls_mutex); return mci;