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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 5AB74C43441 for ; Sun, 11 Nov 2018 20:18:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 180B620854 for ; Sun, 11 Nov 2018 20:18:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 180B620854 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731858AbeKLGFc (ORCPT ); Mon, 12 Nov 2018 01:05:32 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53100 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731493AbeKLGFb (ORCPT ); Mon, 12 Nov 2018 01:05:31 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gLvt6-0000oF-OU; Sun, 11 Nov 2018 19:59:16 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gLvsQ-0001TS-AJ; Sun, 11 Nov 2018 19:58:34 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Felipe Balbi" , "Yoshihiro Shimoda" , "Greg Kroah-Hartman" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 086/366] usb: gadget: function: printer: avoid wrong list handling in printer_write() In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.61-rc1 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 Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings --- drivers/usb/gadget/printer.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/usb/gadget/printer.c +++ b/drivers/usb/gadget/printer.c @@ -667,19 +667,19 @@ 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);