From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752082AbaFIGUP (ORCPT ); Mon, 9 Jun 2014 02:20:15 -0400 Received: from mail.windriver.com ([147.11.1.11]:35362 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750911AbaFIGUN (ORCPT ); Mon, 9 Jun 2014 02:20:13 -0400 From: To: CC: , , , , , Subject: [PATCH v3] USB:gadget: Fix a warning while loading g_mass_storage Date: Mon, 9 Jun 2014 14:19:58 +0800 Message-ID: <1402294798-27401-1-git-send-email-Wei.Yang@windriver.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1401856367-12553-1-git-send-email-Wei.Yang@windriver.com> References: <1401856367-12553-1-git-send-email-Wei.Yang@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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; -- 1.7.9.5