From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1851310-1525116418-2-2427829764630358708 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 en, 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= 1525116417; b=MpctSehZJXHn0JX4ipWvhduNPUO24L0jsRf2DQ+Z4oESP10qqW r7pt+xiZi0bGuNFv6B98qEktzSklsM3W1u4lT6QsNDAeXuPk33AxwIymuVqwLxiQ xUjw3JKZR8CQTdWaXelp59E/5ApgMHGGCKdnbhheIgsCQTJoDr+jBTBvY9vtLY0b Mj8nlYXpSISjJexSnZ+4fqNBjlSArrMOXNCVOkvOPvouHMY/zdD2guXjrPT0glil ZXsOPWjNU4GMwJFOE2df7qC4m/ihNfD8JnbZs4ubQPExzWRwCE8DK3C2/fUFE58i x8mePll+WOjX2tS7ycCaixO2GrIofwKskMMg== 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=1525116417; bh=QQcnvRTAJkaWQfIY+My41VZQN/JRoP Ya+e0s//9DQBw=; b=m8gYaJAXUHTSREzdUW6QK3s7/y8dsHfnUXAYDyTZDvBabc swBm1r4oNAAzWIai+zNnO7i5IbWLjiE+VPe65oyaeUDESytI4gZI5+giAN18lq/D q85rCtf+le2bt5X1FRxIbeL8rspQBlsX0gxDTtHSI4wQhKogDdGNqYgEt5M/221Y Y4b+iaVFC0WC9esF5XdeR9TrGA94D3FCyijigAmczoVest/nQNnYUA2e7TDyEPsJ RJSGDjCPtUK8uSOZUJ+fZiiIo0GVXtE7VIXAl1xg3BIWqyL/rUzdxZ0lvKaKeMpY Xmmb8RI/PnqUMKyIYhOQK3IV4Si+2lVZ/RDoE7rg== ARC-Authentication-Results: i=1; mx4.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: mx4.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: MS4wfOcYhCjO0utlWtSROEPp/NKvDxaYzewnrPWbVhj06XDJJ1TRnR8CbqDrvFzn6FaY/mYeegB+HWTbZlj6C4sUHaAQFGWQYcFD74/WY++r17FXumKbQJze osnZfar8ZQj6pvQQyJinzyHt1kCexXdsQtK/XNrRch7sH20/knOt5AHR1faS4jINlmlEDyy8kgUDMNtEgkL89wzQl3ebgzuZpe01qbv3Wtj2yqVOLiNwOvMp X-CM-Analysis: v=2.3 cv=JLoVTfCb 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 S1755803AbeD3T0x (ORCPT ); Mon, 30 Apr 2018 15:26:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:60634 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755290AbeD3T0v (ORCPT ); Mon, 30 Apr 2018 15:26:51 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41F3F22E03 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 4.9 45/61] ARM: amba: Fix race condition with driver_override Date: Mon, 30 Apr 2018 12:24:48 -0700 Message-Id: <20180430183955.176440110@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180430183951.312721450@linuxfoundation.org> References: <20180430183951.312721450@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: 4.9-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 @@ -69,8 +69,12 @@ 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, @@ -78,7 +82,7 @@ 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; @@ -91,12 +95,15 @@ 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);