From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:46126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936158AbeFNOFv (ORCPT ); Thu, 14 Jun 2018 10:05:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yoshihiro Shimoda , Felipe Balbi Subject: [PATCH 4.17 18/45] usb: gadget: function: printer: avoid wrong list handling in printer_write() Date: Thu, 14 Jun 2018 16:04:09 +0200 Message-Id: <20180614132127.735330833@linuxfoundation.org> In-Reply-To: <20180614132126.797006529@linuxfoundation.org> References: <20180614132126.797006529@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yoshihiro Shimoda commit 4a014a7339f441b0851ce012f469c0fadac61c81 upstream. When printer_write() calls usb_ep_queue(), a udc driver (e.g. renesas_usbhs driver) may call usb_gadget_giveback_request() in the udc .queue ops immediately. Then, printer_write() calls list_add(&req->list, &dev->tx_reqs_active) wrongly. After that, if we do unbind the printer driver, WARN_ON() happens in printer_func_unbind() because the list entry is not removed. So, this patch moves list_add(&req->list, &dev->tx_reqs_active) calling before usb_ep_queue(). Signed-off-by: Yoshihiro Shimoda Acked-by: Felipe Balbi Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_printer.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/usb/gadget/function/f_printer.c +++ b/drivers/usb/gadget/function/f_printer.c @@ -631,19 +631,19 @@ printer_write(struct file *fd, const cha return -EAGAIN; } + list_add(&req->list, &dev->tx_reqs_active); + /* here, we unlock, and only unlock, to avoid deadlock. */ spin_unlock(&dev->lock); value = usb_ep_queue(dev->in_ep, req, GFP_ATOMIC); spin_lock(&dev->lock); if (value) { + list_del(&req->list); list_add(&req->list, &dev->tx_reqs); spin_unlock_irqrestore(&dev->lock, flags); mutex_unlock(&dev->lock_printer_io); return -EAGAIN; } - - list_add(&req->list, &dev->tx_reqs_active); - } spin_unlock_irqrestore(&dev->lock, flags);