From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752231AbaFMGX0 (ORCPT ); Fri, 13 Jun 2014 02:23:26 -0400 Received: from mail.windriver.com ([147.11.1.11]:64827 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751537AbaFMGXZ (ORCPT ); Fri, 13 Jun 2014 02:23:25 -0400 Message-ID: <539A98C3.8080505@windriver.com> Date: Fri, 13 Jun 2014 14:22:59 +0800 From: "Yang,Wei" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: , CC: , , , , , Subject: Re: [PATCH v3] USB:gadget: Fix a warning while loading g_mass_storage References: <1401856367-12553-1-git-send-email-Wei.Yang@windriver.com> <1402294798-27401-1-git-send-email-Wei.Yang@windriver.com> In-Reply-To: <1402294798-27401-1-git-send-email-Wei.Yang@windriver.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [128.224.162.170] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/09/2014 02:19 PM, Wei.Yang@windriver.com wrote: > From: Yang Wei > > While loading g_mass_storage module, the following warning > is triggered. > > WARNING: at drivers/usb/gadget/composite.c: > usb_composite_setup_continue: Unexpected call > Modules linked in: fat vfat minix nls_cp437 nls_iso8859_1 g_mass_storage > [<800179cc>] (unwind_backtrace+0x0/0x104) from [<80619608>] (dump_stack+0x20/0x24) > [<80619608>] (dump_stack+0x20/0x24) from [<80025100>] (warn_slowpath_common+0x64/0x74) > [<80025100>] (warn_slowpath_common+0x64/0x74) from [<800251cc>] (warn_slowpath_fmt+0x40/0x48) > [<800251cc>] (warn_slowpath_fmt+0x40/0x48) from [<7f047774>] (usb_composite_setup_continue+0xb4/0xbc [g_mass_storage]) > [<7f047774>] (usb_composite_setup_continue+0xb4/0xbc [g_mass_storage]) from [<7f047ad4>] (handle_exception+0x358/0x3e4 [g_mass_storage]) > [<7f047ad4>] (handle_exception+0x358/0x3e4 [g_mass_storage]) from [<7f048080>] (fsg_main_thread+0x520/0x157c [g_mass_storage]) > [<7f048080>] (fsg_main_thread+0x520/0x157c [g_mass_storage]) from [<8004bc90>] (kthread+0x98/0x9c) > [<8004bc90>] (kthread+0x98/0x9c) from [<8000faec>] (kernel_thread_exit+0x0/0x8) > > The root cause is that the existing code fails to take into > account the possibility that common->new_fsg can change while > do_set_interface() is running, because the spinlock isn't held > at this point. > > Signed-off-by: Yang Wei > Signed-off-by: Alan Stern > --- > drivers/usb/gadget/f_mass_storage.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > Hi Alan, > > Thanks for your review, there are a few changes in v3: > > 1) Fix a coding style issue. > 2) Refine the commit log > > Regards > Wei Ping, Alan, What do you think of it? Wei > > diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c > index b963939..0cd8f21 100644 > --- a/drivers/usb/gadget/f_mass_storage.c > +++ b/drivers/usb/gadget/f_mass_storage.c > @@ -2342,6 +2342,7 @@ static void handle_exception(struct fsg_common *common) > struct fsg_buffhd *bh; > enum fsg_state old_state; > struct fsg_lun *curlun; > + struct fsg_dev *new_fsg; > unsigned int exception_req_tag; > > /* > @@ -2421,6 +2422,7 @@ static void handle_exception(struct fsg_common *common) > } > common->state = FSG_STATE_IDLE; > } > + new_fsg = common->new_fsg; > spin_unlock_irq(&common->lock); > > /* Carry out any extra actions required for the exception */ > @@ -2460,8 +2462,8 @@ static void handle_exception(struct fsg_common *common) > break; > > case FSG_STATE_CONFIG_CHANGE: > - do_set_interface(common, common->new_fsg); > - if (common->new_fsg) > + do_set_interface(common, new_fsg); > + if (new_fsg) > usb_composite_setup_continue(common->cdev); > break; >