From patchwork Thu Aug 8 09:27:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11083887 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A6B1C1399 for ; Thu, 8 Aug 2019 09:42:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 96E8D28B06 for ; Thu, 8 Aug 2019 09:42:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8B8E228B0A; Thu, 8 Aug 2019 09:42:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E8D528B06 for ; Thu, 8 Aug 2019 09:42:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732155AbfHHJmE (ORCPT ); Thu, 8 Aug 2019 05:42:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:60056 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389813AbfHHJmE (ORCPT ); Thu, 8 Aug 2019 05:42:04 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E8908B06B; Thu, 8 Aug 2019 09:42:02 +0000 (UTC) From: Oliver Neukum To: gregKH@linuxfoundation.org, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [PATCH] usb: iowarrior: fix deadlock on disconnect Date: Thu, 8 Aug 2019 11:27:28 +0200 Message-Id: <20190808092728.23417-1-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We have to drop the mutex before we close() upon disconnect() as close() needs the lock. This is safe to do by dropping the mutex as intfdata is already set to NULL, so open() will fail. Fixes: 03f36e885fc26 ("USB: open disconnect race in iowarrior") Reported-by: syzbot+a64a382964bf6c71a9c0@syzkaller.appspotmail.com Signed-off-by: Oliver Neukum --- drivers/usb/misc/iowarrior.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c index ba05dd80a020..f5bed9f29e56 100644 --- a/drivers/usb/misc/iowarrior.c +++ b/drivers/usb/misc/iowarrior.c @@ -866,19 +866,20 @@ static void iowarrior_disconnect(struct usb_interface *interface) dev = usb_get_intfdata(interface); mutex_lock(&iowarrior_open_disc_lock); usb_set_intfdata(interface, NULL); + /* prevent device read, write and ioctl */ + dev->present = 0; minor = dev->minor; + mutex_unlock(&iowarrior_open_disc_lock); + /* give back our minor - this will call close() locks need to be dropped at this point*/ - /* give back our minor */ usb_deregister_dev(interface, &iowarrior_class); mutex_lock(&dev->mutex); /* prevent device read, write and ioctl */ - dev->present = 0; mutex_unlock(&dev->mutex); - mutex_unlock(&iowarrior_open_disc_lock); if (dev->opened) { /* There is a process that holds a filedescriptor to the device ,