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 ECA063195FC; Thu, 25 Jun 2026 15:13:50 +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=1782400431; cv=none; b=S56dV+m7/xONowQrvZ64eJ8bVAJsg+Nj32hSG3C2dzIOX0eXCsn3whVjwnR0VgC3sZyF4rTARmcVqwwBZxfQvDfBBa6YIiwZ22oCjZyNw71umn4pmzOMRmGCpkRsOV4BK3bLm5UDSsS8VuMSiIfS05tGdE+lEJWV80x3+iTwjdE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782400431; c=relaxed/simple; bh=ycMaEOeVQxdKIIrWEjJbuZSomHZidBI8rEAYR+BgRWE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=g+11DgDdmoUD2UorJiorSO1EdTDx3iVYAQzut2to472o0Y5iuC2en5O8qB5kWcpmOHXHbYFVH+wQZpVA4Tf37v9tQyTX/EhgQMqOQ7V5QODUkJZkFOtjoLyyI0CEbyBfw+J/UjlfVKXBRLOIrLbKMlWdduo8dvIDCDyHw+j3xY8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=08KFvH3Z; 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="08KFvH3Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0BC01F00A3A; Thu, 25 Jun 2026 15:13:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782400430; bh=IrkS9WrqNbaBFJIGMPxWcjnGYNZ94EkJnWjetlLpGi8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=08KFvH3ZVUchGDbWJMdY6009Mm2e0HBnVEzPqbqgMOE9WDhoMXEwu7SOCj9d0GgMC /D0EqrKHr9BDYU61lG6JhsMDhiNrOVdou63Nzg+/eVMh9CXH60a0uoTP4XgxqhQTL5 mI9O3frcJp5SQNArS/N4tkcZ8bvg4lhAnMDkK6ec= Date: Thu, 25 Jun 2026 16:12:38 +0100 From: Greg Kroah-Hartman To: me@samcday.com Cc: Valentina Manea , Shuah Khan , Hongren Zheng , Krzysztof Opasiak , Igor Kotrasinski , Karol Kosik , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] usbip: vudc: fix NULL deref in vep_dequeue() Message-ID: <2026062518-treason-styling-5185@gregkh> References: <20260620-usbip-vudc-deque-fix-v2-1-d1913ab4611b@samcday.com> Precedence: bulk X-Mailing-List: linux-usb@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: <20260620-usbip-vudc-deque-fix-v2-1-d1913ab4611b@samcday.com> On Sat, Jun 20, 2026 at 10:18:09AM +1000, Sam Day via B4 Relay wrote: > From: Sam Day > > vep_alloc_request() wasn't initializing vrequest->udc, so cancellations > on the FunctionFS AIO path were arriving in vep_dequeue without a valid > UDC reference. > > Since vrequest->udc is never actually properly used anywhere, we opt to > remove it, and update vep_dequeue to obtain a reference to the udc with > ep_to_vudc(), consistent with the other vep_ ops. > > AFAICT this bug has existed for ~10 years. Seems that nobody has really > stressed the FunctionFS AIO path on usbip's vudc. > > I tested this fix in a QEMU aarch64 guest driving FunctionFS endpoints > via AIO. Before the fix, running `usbip attach` from the host would > cause the guest to oops with the following backtrace: > > Call trace: > vep_dequeue+0x1c/0xe4 (P) > usb_ep_dequeue+0x14/0x20 > ffs_aio_cancel+0x24/0x34 > __arm64_sys_io_cancel+0xb0/0x124 > do_el0_svc+0x68/0x100 > el0_svc+0x18/0x5c > el0t_64_sync_handler+0x98/0xdc > el0t_64_sync+0x154/0x158 > > Assisted-by: opencode:openai/gpt-5.5 > Fixes: b6a0ca111867 ("usbip: vudc: Add UDC specific ops") > Signed-off-by: Sam Day > --- > Changes in v2: > - Reworked to remove vrequest->udc entirely and a call to ep_to_vudc() > from vep_deqe > - Link to v1: https://lore.kernel.org/r/20260619-usbip-vudc-deque-fix-v1-1-9021463b1903@samcday.com > --- > drivers/usb/usbip/vudc.h | 1 - > drivers/usb/usbip/vudc_dev.c | 2 +- > 2 files changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/usb/usbip/vudc.h b/drivers/usb/usbip/vudc.h > index faf61c9c6a98..5ef0e7d9b23a 100644 > --- a/drivers/usb/usbip/vudc.h > +++ b/drivers/usb/usbip/vudc.h > @@ -38,7 +38,6 @@ struct vep { > > struct vrequest { > struct usb_request req; > - struct vudc *udc; > struct list_head req_entry; /* Request queue */ > }; > > diff --git a/drivers/usb/usbip/vudc_dev.c b/drivers/usb/usbip/vudc_dev.c > index c5f079c5a1ea..f0a1a44c18e3 100644 > --- a/drivers/usb/usbip/vudc_dev.c > +++ b/drivers/usb/usbip/vudc_dev.c > @@ -344,7 +344,7 @@ static int vep_dequeue(struct usb_ep *_ep, struct usb_request *_req) > > ep = to_vep(_ep); > req = to_vrequest(_req); > - udc = req->udc; > + udc = ep_to_vudc(ep); Why is "req" still needed now? Shouldn't that variable be removed also? thanks, greg k-h