From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3986551118D; Fri, 4 Sep 2026 17:10:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788541834; cv=none; b=h7xReteO9VQNm/4wxVkyV959V+xRvSToGvufdG7yqFVPgPxd6/SPfIvKcyZRmG2GEi/Mx6EtYSKHPiM7G4U+cgztljvApMf3AWGBoAp44GYPZGs/3NYRFOM4t7CHF//FTYj3wjJ1xpBAxK9P2lKoderSZOAS4ERpeZPUbSA9dCM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788541834; c=relaxed/simple; bh=gA6fqD4jeawG/r3uXp7hAR7LuJriNp0pXhV+O2ZhR2E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=O8Wk9o6Ec8ptlOs5q9jse3rWJDkNMip+lFQB+scxRrix81uz2v0xwiKBsvWytPmdWGbI8AZN4tOhmcHHEM+gl//d3twLeyzWD4z4saOvxTHH1e5q5wJyat62ChVoxi+UwaBj3J1wnzTY/KoS8KhRnYOUMxu97jnU18p1H20Yd/k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=M7wvoiU2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="M7wvoiU2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D9C01F00A3D; Fri, 4 Sep 2026 17:10:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788541831; bh=DLyBHdBCiwFaJqCNC3f7TEdHuUZXCH0w7XfvGLQL/Ok=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=M7wvoiU2Ad4m317yVhPA29adVTn/XoSCL5MdaOA1H+DQ2ictbMGs7zoklNWPyPYUf cdTZZMTtbgcCoJhCFBcoDT7n1TwVO+Wkpom5xyFdEJ613Js4Jf4uF4A+C0kMkgDsKZ 0N2tvqv2E9rjNI0yaBVw7flJVOTplT+qMWmrxe5o= Date: Fri, 4 Sep 2026 19:07:50 +0200 From: Greg Kroah-Hartman To: Cole Munz Cc: Thinh Nguyen , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] usb: dwc3: gadget: don't error on dequeue of a completed request Message-ID: <2026090413-hurdle-puzzling-aadd@gregkh> References: <20260904161344.2191362-1-Munzzyy1@proton.me> <2026090406-unrevised-stays-4832@gregkh> <7bef11b63feb88f89b37bbc86323ed3dba794f43.1788541086.git.Munzzyy1@proton.me> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7bef11b63feb88f89b37bbc86323ed3dba794f43.1788541086.git.Munzzyy1@proton.me> On Fri, Sep 04, 2026 at 04:58:57PM +0000, Cole Munz wrote: > Dequeuing a request that has already been given back logs an error and > returns -EINVAL: > > dwc3 23000000.usb: request 00000000ad92f1c4 was not queued to ep0out > > f_fs hits this on every teardown. functionfs_unbind() dequeues ep0req > unconditionally before freeing it, which > commit ce405d561b02 ("usb: gadget: f_fs: Ensure ep0req is dequeued > before free_request") made deliberate to close a use-after-free. By then > the control transfer has long completed, so dwc3_gadget_ep_dequeue() > finds the request on none of cancelled_list, pending_list or > started_list and falls through to the error path. > > Nothing is actually wrong. The request is not queued, which is what the > caller asked for, and both callers ignore the return value and free the > request straight after. The only effect is an error line in every gadget > teardown, which buries real USB errors. > > dwc3 already tracks enough to tell the two cases apart. > dwc3_gadget_ep_alloc_request() sets DWC3_REQUEST_STATUS_UNKNOWN, both > __dwc3_gadget_ep_queue() and __dwc3_gadget_ep0_queue() set > DWC3_REQUEST_STATUS_QUEUED, and dwc3_gadget_giveback() sets > DWC3_REQUEST_STATUS_COMPLETED. A request that reaches the end of dequeue > with status COMPLETED was queued to this endpoint and has finished. > Anything else was never queued here, or the driver lost track of it. > Keep the error for those, and return success for a completed request. > > A completed request still has to be dequeued on the endpoint it belongs > to. req->dep is set once at allocation and never changes, and > __dwc3_gadget_ep_queue() rejects the same mismatch with a WARN, so a > wrong-endpoint dequeue stays on the error path here as well. > > This is narrower than the cdnsp fix for the same caller, > commit 34f08eb0ba6e ("usb: cdnsp: Fixes issue with dequeuing not queued > requests"), which returns 0 whenever usb_request::status is not > -EINPROGRESS. That also swallows a request that was never queued, since > status is zero out of allocation. Going by dwc3's own request status > keeps that case an error, which is what was asked for when a separate > ep0 dequeue was proposed in 2022. > > Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver") > Cc: stable@vger.kernel.org > Link: https://lore.kernel.org/linux-usb/20221117054917.30104-1-quic_ugoswami@quicinc.com/ > Assisted-by: LLM sparse > Signed-off-by: Cole Munz > --- > All three were missing, sorry about that. > > v2: add Fixes:, Cc: stable and Assisted-by tags. No code change. > > drivers/usb/dwc3/gadget.c | 19 ++++++++++++++++--- > 1 file changed, 16 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > index fa944856f956..f68eb9254afa 100644 > --- a/drivers/usb/dwc3/gadget.c > +++ b/drivers/usb/dwc3/gadget.c > @@ -2181,9 +2181,22 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep, > } > } > > - dev_err(dwc->dev, "request %p was not queued to %s\n", > - request, ep->name); > - ret = -EINVAL; > + /* > + * The request is on none of this endpoint's lists. That is the > + * expected state once it has been given back: a function may dequeue > + * a request before freeing it, and f_fs does so unconditionally for > + * ep0req in functionfs_unbind(). Nothing is queued, which is what the > + * caller asked for, so report success. Any other status means the > + * request was never queued here or the driver lost track of it, and > + * stays an error. So does a completed request handed to the wrong > + * endpoint: req->dep is fixed at allocation, and the queue side > + * rejects the same mismatch. > + */ LLMs love to add long comments like this that make almost no sense. Please rewrite this in a human voice, being very concise, if you still feel a comment is needed. thanks, greg k-h