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=-5.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,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 6B339C04A6B for ; Mon, 6 May 2019 15:10:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A2072053B for ; Mon, 6 May 2019 15:10:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557155447; bh=JjMQHWf7en1JnPMl25Brc/ONJrEvJ0JAbONFCKfVaBs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JHycSiYqeo0mb78cuA9WPGhwX2HghLESY8whZ6xx89Etf7L46oQeDLJU46i/x3AKc o2/5BuVyKcyBdC2otdgomrM2ZCjOmXtWF0mwHk8WzfWBEJ/Gm2FWONZRsG7WHzPgmT zHUTGXJv2xNKfU+FAyY/1XiBqmCJ9XaijbTCNhEs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726526AbfEFOeJ (ORCPT ); Mon, 6 May 2019 10:34:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:53586 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726489AbfEFOeE (ORCPT ); Mon, 6 May 2019 10:34:04 -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 B7ADD204EC; Mon, 6 May 2019 14:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557153243; bh=JjMQHWf7en1JnPMl25Brc/ONJrEvJ0JAbONFCKfVaBs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wrjwHLyeqwIJRXPLLuKgd5U7OW8jP8mEQOG3+btqwsMf4bKmqNsJjRru9sYFGuLSD tCRRY7d9GPLB18Oqsj2Y+Zvn96FM82Gg4vpr13o8TLFnm8T8U6u3/qDE/JU5vnkd4F M1ZNVzTQHVOQZZUCvvr7VtBs/CEMhghs98GIWYlw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , syzbot+d919b0f29d7b5a4994b9@syzkaller.appspotmail.com Subject: [PATCH 5.0 016/122] USB: dummy-hcd: Fix failure to give back unlinked URBs Date: Mon, 6 May 2019 16:31:14 +0200 Message-Id: <20190506143056.202398219@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190506143054.670334917@linuxfoundation.org> References: <20190506143054.670334917@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alan Stern commit fc834e607ae3d18e1a20bca3f9a2d7f52ea7a2be upstream. The syzkaller USB fuzzer identified a failure mode in which dummy-hcd would never give back an unlinked URB. This causes usb_kill_urb() to hang, leading to WARNINGs and unkillable threads. In dummy-hcd, all URBs are given back by the dummy_timer() routine as it scans through the list of pending URBS. Failure to give back URBs can be caused by failure to start or early exit from the scanning loop. The code currently has two such pathways: One is triggered when an unsupported bus transfer speed is encountered, and the other by exhausting the simulated bandwidth for USB transfers during a frame. This patch removes those two paths, thereby allowing all unlinked URBs to be given back in a timely manner. It adds a check for the bus speed when the gadget first starts running, so that dummy_timer() will never thereafter encounter an unsupported speed. And it prevents the loop from exiting as soon as the total bandwidth has been used up (the scanning loop continues, giving back unlinked URBs as they are found, but not transferring any more data). Thanks to Andrey Konovalov for manually running the syzkaller fuzzer to help track down the source of the bug. Signed-off-by: Alan Stern Reported-and-tested-by: syzbot+d919b0f29d7b5a4994b9@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/udc/dummy_hcd.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) --- a/drivers/usb/gadget/udc/dummy_hcd.c +++ b/drivers/usb/gadget/udc/dummy_hcd.c @@ -979,8 +979,18 @@ static int dummy_udc_start(struct usb_ga struct dummy_hcd *dum_hcd = gadget_to_dummy_hcd(g); struct dummy *dum = dum_hcd->dum; - if (driver->max_speed == USB_SPEED_UNKNOWN) + switch (g->speed) { + /* All the speeds we support */ + case USB_SPEED_LOW: + case USB_SPEED_FULL: + case USB_SPEED_HIGH: + case USB_SPEED_SUPER: + break; + default: + dev_err(dummy_dev(dum_hcd), "Unsupported driver max speed %d\n", + driver->max_speed); return -EINVAL; + } /* * SLAVE side init ... the layer above hardware, which @@ -1784,9 +1794,10 @@ static void dummy_timer(struct timer_lis /* Bus speed is 500000 bytes/ms, so use a little less */ total = 490000; break; - default: + default: /* Can't happen */ dev_err(dummy_dev(dum_hcd), "bogus device speed\n"); - return; + total = 0; + break; } /* FIXME if HZ != 1000 this will probably misbehave ... */ @@ -1828,7 +1839,7 @@ restart: /* Used up this frame's bandwidth? */ if (total <= 0) - break; + continue; /* find the gadget's ep for this request (if configured) */ address = usb_pipeendpoint (urb->pipe);