From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754058Ab2HDECp (ORCPT ); Sat, 4 Aug 2012 00:02:45 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:45263 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751005Ab2HDECj (ORCPT ); Sat, 4 Aug 2012 00:02:39 -0400 From: Ming Lei To: Linus Torvalds , Greg Kroah-Hartman Cc: "Rafael J. Wysocki" , Borislav Petkov , linux-kernel@vger.kernel.org, Ming Lei Subject: [RFC PATCH v1 08/15] firmware loader: fix device lifetime Date: Sat, 4 Aug 2012 12:01:23 +0800 Message-Id: <1344052890-31935-9-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1344052890-31935-1-git-send-email-ming.lei@canonical.com> References: <1344052890-31935-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Callers of request_firmware* must hold the reference count of @device, otherwise it is easy to trigger oops since the firmware loader device is the child of @device. This patch adds comments about the usage. In fact, most of drivers call request_firmware* in its probe() or open(), so the constraint should be reasonable and can be satisfied. Also this patch holds the reference count of @device before schedule_work() in request_firmware_nowait() to avoid that the @device is released after request_firmware_nowait returns and before the worker function is scheduled. Signed-off-by: Ming Lei --- drivers/base/firmware_class.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index fc119ce..7d3a83b 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -742,6 +742,8 @@ err_put_dev: * @name will be used as $FIRMWARE in the uevent environment and * should be distinctive enough not to be confused with any other * firmware image for this or any other device. + * + * Caller must hold the reference count of @device. **/ int request_firmware(const struct firmware **firmware_p, const char *name, @@ -823,6 +825,7 @@ static void request_firmware_work_func(struct work_struct *work) out: fw_work->cont(fw, fw_work->context); + put_device(fw_work->device); module_put(fw_work->module); kfree(fw_work); @@ -841,6 +844,8 @@ static void request_firmware_work_func(struct work_struct *work) * @cont: function will be called asynchronously when the firmware * request is over. * + * Caller must hold the reference count of @device. + * * Asynchronous variant of request_firmware() for user contexts where * it is not possible to sleep for long time. It can't be called * in atomic contexts. @@ -869,6 +874,7 @@ request_firmware_nowait( return -EFAULT; } + get_device(fw_work->device); INIT_WORK(&fw_work->work, request_firmware_work_func); schedule_work(&fw_work->work); return 0; -- 1.7.9.5