From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1936261-1525120423-2-16641978153297731787 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES enca, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1525120423; b=BcPLCCBChAtFX0orvtOwm/cSQCp7zsLY/iPZQ7MOEIk2OGqOLm jk89207oTgZNsqdWYkxMEmzjX24CSsxYGfFXFhUB+P09FZURxkHhsPHmq4bwAKVa dONfWzvFEJGh5l7gmWvFa+CtGaAHPKbm3u0AMx6izEBINN/oAkL6KGpJmbP0tchE WOks4AItkxTLNCC6/2S+EA0b7axO49hPpz73KbzRMMu6kyhN32QVOxM084Ey2id4 XJo+lAS8bjiJJs7Ik79P5CHwT6/3Kc+7lYunvPOL8A0Iv7Uv09V6U602ZJcnBEvK ZBKac15NXyGEBUEIR0bSCDHZvb8F2iKMmALg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1525120423; bh=83NSl0JFzZdCbw/whskBZIGi3t4s9V fIwR7NKJkdyH4=; b=bihslXXoeZRV0Pw7YceA697QhAvethLf0XlQZVkWOOs1Vf Ld1jyrNN5bfyWpK7CDrqkQxeoGJsozl/tELFS23h/qYBMLu7NOk9ATAf3a/h9a8S qL0G95R3EeYb0pxafNxFhCD2J4EvfYsOMwAVB3rgt3pQL2Z1e1VHFTycjGQCGTWZ QgwvPE2Ry9PEmwf5pMnd9cjukHS4oyeRGwLOiZtKBoXdVjKKZiKZlJ4n0yd5BGG7 zBh0K+7lrwuvduJpwmI4Cy9yaQuSabI2Untj+f0aIr1nBXFL6x8i6yggtwu/D5/9 u51lmh39N6dSEyxoghb6Fbv2ZqZhlviLC6ipVuwA== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfC3Y85kv7ZTymXLQ6agPWuZtwaqs+uH2BcERE1Hzs8nYWm62CA/6iuq9GQXgn3bumN5KS/j4N+GfaYwgsxX2NAKQ85b6Mmhbz7Bbg0oBQIJLdSCk/+Jf C1E89Nd04HRpXEBR1Q7D4ZvFwGqbh56aKVRDI9qOvkMnE9/9Pb8za+QNm0lXBOf9dNhDPbD+GQ4caxVJ3UCqTtGxshc2Fz71JYjXUtVtjrgtMD90q9YZ9gwZ X-CM-Analysis: v=2.3 cv=NPP7BXyg c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=Kd1tUaAdevIA:10 a=1XWaLZrsAAAA:8 a=VwQbUJbxAAAA:8 a=ag1SF4gXAAAA:8 a=5EMsjEJVl8QOgak0-BcA:9 a=QEXdDO2ut3YA:10 a=AjGcO6oz07-iQ99wixmX:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755492AbeD3Uc7 (ORCPT ); Mon, 30 Apr 2018 16:32:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:59250 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755463AbeD3T0D (ORCPT ); Mon, 30 Apr 2018 15:26:03 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FF7F22DC2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Geert Uytterhoeven , Todd Kjos Subject: [PATCH 4.4 36/44] ARM: amba: Fix race condition with driver_override Date: Mon, 30 Apr 2018 12:24:47 -0700 Message-Id: <20180430190947.776165866@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180430190946.093694747@linuxfoundation.org> References: <20180430190946.093694747@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Geert Uytterhoeven commit 6a7228d90d42bcacfe38786756ba62762b91c20a upstream. The driver_override implementation is susceptible to a race condition when different threads are reading vs storing a different driver override. Add locking to avoid this race condition. Cfr. commits 6265539776a0810b ("driver core: platform: fix race condition with driver_override") and 9561475db680f714 ("PCI: Fix race condition with driver_override"). Fixes: 3cf385713460eb2b ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'") Signed-off-by: Geert Uytterhoeven Reviewed-by: Todd Kjos Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/amba/bus.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -68,8 +68,12 @@ static ssize_t driver_override_show(stru struct device_attribute *attr, char *buf) { struct amba_device *dev = to_amba_device(_dev); + ssize_t len; - return sprintf(buf, "%s\n", dev->driver_override); + device_lock(_dev); + len = sprintf(buf, "%s\n", dev->driver_override); + device_unlock(_dev); + return len; } static ssize_t driver_override_store(struct device *_dev, @@ -77,7 +81,7 @@ static ssize_t driver_override_store(str const char *buf, size_t count) { struct amba_device *dev = to_amba_device(_dev); - char *driver_override, *old = dev->driver_override, *cp; + char *driver_override, *old, *cp; if (count > PATH_MAX) return -EINVAL; @@ -90,12 +94,15 @@ static ssize_t driver_override_store(str if (cp) *cp = '\0'; + device_lock(_dev); + old = dev->driver_override; if (strlen(driver_override)) { dev->driver_override = driver_override; } else { kfree(driver_override); dev->driver_override = NULL; } + device_unlock(_dev); kfree(old);