Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756750Ab3EJO1b (ORCPT ); Fri, 10 May 2013 10:27:31 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57283 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756001Ab3EJOWA (ORCPT ); Fri, 10 May 2013 10:22:00 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Greg Kroah-Hartman" , "Federico Vaga" Date: Fri, 10 May 2013 14:39:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [032/118] serial_core.c: add put_device() after device_find_child() In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:d51a:8785:aa0a:cebe X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3328 Lines: 103 3.2.45-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Federico Vaga commit 5a65dcc04cda41f4122aacc37a5a348454645399 upstream. The serial core uses device_find_child() but does not drop the reference to the retrieved child after using it. This patch add the missing put_device(). What I have done to test this issue. I used a machine with an AMBA PL011 serial driver. I tested the patch on next-20120408 because the last branch [next-20120415] does not boot on this board. For test purpose, I added some pr_info() messages to print the refcount after device_find_child() (lines: 1937,2009), and after put_device() (lines: 1947, 2021). Boot the machine *without* put_device(). Then: echo reboot > /sys/power/disk echo disk > /sys/power/state [ 87.058575] uart_suspend_port:1937 refcount 4 [ 87.058582] uart_suspend_port:1947 refcount 4 [ 87.098083] uart_resume_port:2009refcount 5 [ 87.098088] uart_resume_port:2021 refcount 5 echo disk > /sys/power/state [ 103.055574] uart_suspend_port:1937 refcount 6 [ 103.055580] uart_suspend_port:1947 refcount 6 [ 103.095322] uart_resume_port:2009 refcount 7 [ 103.095327] uart_resume_port:2021 refcount 7 echo disk > /sys/power/state [ 252.459580] uart_suspend_port:1937 refcount 8 [ 252.459586] uart_suspend_port:1947 refcount 8 [ 252.499611] uart_resume_port:2009 refcount 9 [ 252.499616] uart_resume_port:2021 refcount 9 The refcount continuously increased. Boot the machine *with* this patch. Then: echo reboot > /sys/power/disk echo disk > /sys/power/state [ 159.333559] uart_suspend_port:1937 refcount 4 [ 159.333566] uart_suspend_port:1947 refcount 3 [ 159.372751] uart_resume_port:2009 refcount 4 [ 159.372755] uart_resume_port:2021 refcount 3 echo disk > /sys/power/state [ 185.713614] uart_suspend_port:1937 refcount 4 [ 185.713621] uart_suspend_port:1947 refcount 3 [ 185.752935] uart_resume_port:2009 refcount 4 [ 185.752940] uart_resume_port:2021 refcount 3 echo disk > /sys/power/state [ 207.458584] uart_suspend_port:1937 refcount 4 [ 207.458591] uart_suspend_port:1947 refcount 3 [ 207.498598] uart_resume_port:2009 refcount 4 [ 207.498605] uart_resume_port:2021 refcount 3 The refcount correctly handled. Signed-off-by: Federico Vaga Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/tty/serial/serial_core.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1901,6 +1901,8 @@ int uart_suspend_port(struct uart_driver mutex_unlock(&port->mutex); return 0; } + put_device(tty_dev); + if (console_suspend_enabled || !uart_console(uport)) uport->suspended = 1; @@ -1966,9 +1968,11 @@ int uart_resume_port(struct uart_driver disable_irq_wake(uport->irq); uport->irq_wake = 0; } + put_device(tty_dev); mutex_unlock(&port->mutex); return 0; } + put_device(tty_dev); uport->suspended = 0; /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/