From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E6B2C43381 for ; Mon, 1 Apr 2019 17:35:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F47520830 for ; Mon, 1 Apr 2019 17:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140114; bh=Wkmjcgy4nUN0i65BuBCOoOOHKKjbqhGyr5XDgqHYlZM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PjpdBtgs70V368rV6DJu3bql2Oru03ns3KSMDNyCjze/1Qrl0irhODd5ejdpvlhb2 OPW1tmSgXridvYDZsPKV3Os8UXd82vTan8s2bhY/JmNZ1nWK2WpWIC25AcLJChziFl jOsSVCwWSjBOim3wgfbNMxlBnwhx1zNrH6IVbnrE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387875AbfDARfN (ORCPT ); Mon, 1 Apr 2019 13:35:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:45664 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387527AbfDARfM (ORCPT ); Mon, 1 Apr 2019 13:35:12 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EFFE820880; Mon, 1 Apr 2019 17:35:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140111; bh=Wkmjcgy4nUN0i65BuBCOoOOHKKjbqhGyr5XDgqHYlZM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sUFpTxGpEqVPMXZPwAtOBSJZUGT3n0yOcxLYcMcOL9ObvyhCepe9QoUxkKyuYeK6P 186iqzafVaETtzM6WvWxcMpsZa1mijztPeMnfzOspo1SWov1gM9APGnkgky9ESTpFb m9gI/9r7FxS0JDdFoac1ZvYeITbMwfdqFQJmY/b0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Winter Wang , Felipe Balbi , Sasha Levin Subject: [PATCH 4.4 082/131] usb: gadget: configfs: add mutex lock before unregister gadget Date: Mon, 1 Apr 2019 19:02:32 +0200 Message-Id: <20190401170058.971706294@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170051.645954551@linuxfoundation.org> References: <20190401170051.645954551@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit cee51c33f52ebf673a088a428ac0fecc33ab77fa ] There may be a race condition if f_fs calls unregister_gadget_item in ffs_closed() when unregister_gadget is called by UDC store at the same time. this leads to a kernel NULL pointer dereference: [ 310.644928] Unable to handle kernel NULL pointer dereference at virtual address 00000004 [ 310.645053] init: Service 'adbd' is being killed... [ 310.658938] pgd = c9528000 [ 310.662515] [00000004] *pgd=19451831, *pte=00000000, *ppte=00000000 [ 310.669702] Internal error: Oops: 817 [#1] PREEMPT SMP ARM [ 310.675211] Modules linked in: [ 310.678294] CPU: 0 PID: 1537 Comm: ->transport Not tainted 4.1.15-03725-g793404c #2 [ 310.685958] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) [ 310.692493] task: c8e24200 ti: c945e000 task.ti: c945e000 [ 310.697911] PC is at usb_gadget_unregister_driver+0xb4/0xd0 [ 310.703502] LR is at __mutex_lock_slowpath+0x10c/0x16c [ 310.708648] pc : [] lr : [] psr: 600f0113 [ 311.565585] [] (usb_gadget_unregister_driver) from [] (unregister_gadget_item+0x1c/0x34) [ 311.575426] [] (unregister_gadget_item) from [] (ffs_closed+0x8c/0x9c) [ 311.583702] [] (ffs_closed) from [] (ffs_data_reset+0xc/0xa0) [ 311.591194] [] (ffs_data_reset) from [] (ffs_data_closed+0x90/0xd0) [ 311.599208] [] (ffs_data_closed) from [] (ffs_ep0_release+0xc/0x14) [ 311.607224] [] (ffs_ep0_release) from [] (__fput+0x80/0x1d0) [ 311.614635] [] (__fput) from [] (task_work_run+0xb0/0xe8) [ 311.621788] [] (task_work_run) from [] (do_work_pending+0x7c/0xa4) [ 311.629718] [] (do_work_pending) from [] (work_pending+0xc/0x20) for functions using functionFS, i.e. android adbd will close /dev/usb-ffs/adb/ep0 when usb IO thread fails, but switch adb from on to off also triggers write "none" > UDC. These 2 operations both call unregister_gadget, which will lead to the panic above. add a mutex before calling unregister_gadget for api used in f_fs. Signed-off-by: Winter Wang Signed-off-by: Felipe Balbi Signed-off-by: Sasha Levin --- drivers/usb/gadget/configfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index 6abb6a10ee82..d412e234f336 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -1496,7 +1496,9 @@ void unregister_gadget_item(struct config_item *item) { struct gadget_info *gi = to_gadget_info(item); + mutex_lock(&gi->lock); unregister_gadget(gi); + mutex_unlock(&gi->lock); } EXPORT_SYMBOL_GPL(unregister_gadget_item); -- 2.19.1