From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:40528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753676AbeDZIfl (ORCPT ); Thu, 26 Apr 2018 04:35:41 -0400 Subject: patch "ARM: amba: Fix race condition with driver_override" added to char-misc-linus To: geert+renesas@glider.be, gregkh@linuxfoundation.org, stable@vger.kernel.org, tkjos@google.com From: Date: Thu, 26 Apr 2018 10:35:12 +0200 Message-ID: <152473171225121@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ARM: amba: Fix race condition with driver_override to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >>From 6a7228d90d42bcacfe38786756ba62762b91c20a Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 10 Apr 2018 15:21:44 +0200 Subject: ARM: amba: Fix race condition with driver_override 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 --- drivers/amba/bus.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index f8c01fbef64d..4a3ac31c07d0 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -69,8 +69,12 @@ static ssize_t driver_override_show(struct device *_dev, 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(struct device *_dev, 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; /* We need to keep extra room for a newline */ if (count >= (PAGE_SIZE - 1)) @@ -92,12 +96,15 @@ static ssize_t driver_override_store(struct device *_dev, 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); -- 2.17.0