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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 8DE92C35254 for ; Mon, 10 Feb 2020 19:04:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A6B02080C for ; Mon, 10 Feb 2020 19:04:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581361466; bh=AFgD6yboFm7FOthsnmhCQT4RoIp6cfaXMDxquhOOyKI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=bEhAvoLywLDn3V9h1PxYNUufk/CxFTG3IxngSNKS/Rp4vmm6ZZGlnWJQT0s9SN1ly IZe43WfAB0VNF90A20ApGrZ6J49bL5D2xfOMBffhv4YqChYOnEp5lxbTM77XFrCd44 0S1MWaq/KTEbBqUfTvuXwiwrdYhJ+GaWv4JFY0jc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727054AbgBJTEW (ORCPT ); Mon, 10 Feb 2020 14:04:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:39026 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726831AbgBJTEW (ORCPT ); Mon, 10 Feb 2020 14:04:22 -0500 Received: from localhost (unknown [104.132.1.111]) (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 590592080C; Mon, 10 Feb 2020 19:04:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581361460; bh=AFgD6yboFm7FOthsnmhCQT4RoIp6cfaXMDxquhOOyKI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DW5Zh/4t4VXQlbOMIdk3zlSNpDHgMj/RpVNS2BL7mthv3qF5DUkTxEDoEckEMBCXG wBlkN3z1eRavm9iBlwZjFqMXgz06jQkuCCkpJ+sVn9VoXkbrPGklVjWjwETE/E/fW/ U4ryYv0SAT251feye1DOc2FX0eE7t3aEhTJ0h5XI= Date: Mon, 10 Feb 2020 11:04:19 -0800 From: Greg KH To: Dan Carpenter Cc: Alan Stern , syzbot , andreyknvl@google.com, ingrassia@epigenesys.com, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [PATCH] usb: core: urb: change a dev_WARN() to dev_err() for syzbot Message-ID: <20200210190419.GC1058087@kroah.com> References: <00000000000095e1d8059d4675ac@google.com> <20200131050651.hlq27kehtir3agf2@kili.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200131050651.hlq27kehtir3agf2@kili.mountain> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Fri, Jan 31, 2020 at 08:06:52AM +0300, Dan Carpenter wrote: > We changed this from dev_err() to dev_WARN() in commit 0cb54a3e47cb > ("USB: debugging code shouldn't alter control flow"). > > The difference between dev_WARN() and dev_err() is that dev_WARN() > prints a stack trace and if you have panic on OOPS enabled then it leads > to a panic. The dev_err() function just prints the error message. > > Back in the day we didn't have usb emulators fuzz testing the kernel > so dev_WARN() didn't cause a problem for anyone, but these days the > dev_WARN() interferes with syzbot so let's change this to a dev_err(). > > Reported-by: syzbot+1bc2c2afd44f820a669f@syzkaller.appspotmail.com > Signed-off-by: Dan Carpenter > --- > > drivers/usb/core/urb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c > index da923ec17612..0980c1d2253d 100644 > --- a/drivers/usb/core/urb.c > +++ b/drivers/usb/core/urb.c > @@ -475,7 +475,7 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) > > /* Check that the pipe's type matches the endpoint's type */ > if (usb_urb_ep_type_check(urb)) > - dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n", > + dev_err(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n", > usb_pipetype(urb->pipe), pipetypes[xfertype]); Like others said, we should have the stack trace here. So can you change this to dev_warn() and a stacktrace? thanks, greg k-h