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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS 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 27CCAC10F13 for ; Tue, 16 Apr 2019 21:14:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2E5620821 for ; Tue, 16 Apr 2019 21:14:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729300AbfDPVOk (ORCPT ); Tue, 16 Apr 2019 17:14:40 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:43688 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1728052AbfDPVOj (ORCPT ); Tue, 16 Apr 2019 17:14:39 -0400 Received: (qmail 14034 invoked by uid 2102); 16 Apr 2019 17:14:38 -0400 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 16 Apr 2019 17:14:38 -0400 Date: Tue, 16 Apr 2019 17:14:38 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: syzbot cc: andreyknvl@google.com, , , , , Subject: Re: INFO: task hung in usb_kill_urb In-Reply-To: <000000000000fb61d40586aa6a1e@google.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Apr 2019, syzbot wrote: > Hello, > > syzbot has tested the proposed patch and the reproducer did not trigger > crash: Slight fixup to the patch. Unsupported speeds aren't necessarily bogus, and what matters is the actual speed rather than the max_speed. Also, we want to be able to give back unlinked URBs even after a frame's total bandwidth has been exhausted. Alan Stern #syz test: https://github.com/google/kasan.git usb-fuzzer --- 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 @@ -1784,7 +1794,7 @@ 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; } @@ -1828,7 +1838,7 @@ 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);