From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4339B1799D; Thu, 25 Jul 2024 04:56:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721883383; cv=none; b=uqwh41vws17E6JghhQlsWblB6YGaymtX0dnAyoggBZQmP0HptrTgDsXoC2uFYR3IXVunuyTEUrnNj5E/u5pRjUpdRy/0ZXTsIaiBv/yWhcqHBa15tI8yhXc3SXWQd0VMdff9i8tW6oK31CbtGFF6n+IBXWO3w6T53ZlEdMv61ZM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721883383; c=relaxed/simple; bh=zk/VhAHN1LPunJ+YJmUalCWwGgZ5WsvNLPHEGNo3DhM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=t9uI9f7n25MszQ+ru7qFB7bASbOFN6JanyZZDlw5F6DsK0Jm/yqH1Q64c3WxEexrpXuS+Vxe/+E5y1ptA1AeCfl4KjapHVrCeofhjnKKn+b+01U/JR5enHFXdbrCx40xu98xpSVzGFu/WIpidNJ2pt8pKlPdnfMxhEydHeyVZVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=w039w93K; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="w039w93K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52A14C116B1; Thu, 25 Jul 2024 04:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1721883382; bh=zk/VhAHN1LPunJ+YJmUalCWwGgZ5WsvNLPHEGNo3DhM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=w039w93KtKKREIAq9lY6f4/SJCMwGs1O5VIHAOZkgdJeZjpH99r/5aCIE+4GfeiRF wmglW/z+fQs2+2QUr4hd/8HTAFyDy+E+Zp1V/+WAOV9j0MTnhqUEoH5qauo/ix1w2t JcydWzM4H8SiPyJWCMJIK3wyK/mFQ9EXCYLYEWXk= Date: Thu, 25 Jul 2024 06:56:19 +0200 From: Greg Kroah-Hartman To: crwulff@gmail.com Cc: linux-usb@vger.kernel.org, Alan Stern , Roy Luo , Krishna Kurapati , Michael Grzeschik , yuan linyu , Paul Cercueil , Felipe Balbi , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] usb: gadget: core: Check for unset descriptor Message-ID: <2024072512-arguably-creole-a017@gregkh> References: <20240725010419.314430-2-crwulff@gmail.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: <20240725010419.314430-2-crwulff@gmail.com> On Wed, Jul 24, 2024 at 09:04:20PM -0400, crwulff@gmail.com wrote: > From: Chris Wulff > > Make sure the descriptor has been set before looking at maxpacket. > This fixes a null pointer panic in this case. > > This may happen if the gadget doesn't properly set up the endpoint > for the current speed, or the gadget descriptors are malformed and > the descriptor for the speed/endpoint are not found. > > No current gadget driver is known to have this problem, but this > may cause a hard-to-find bug during development of new gadgets. > > Fixes: 54f83b8c8ea9 ("USB: gadget: Reject endpoints with 0 maxpacket value") > Cc: stable@vger.kernel.org > Signed-off-by: Chris Wulff > --- > v2: Added WARN_ONCE message & clarification on causes > v1: https://lore.kernel.org/all/20240721192048.3530097-2-crwulff@gmail.com/ > --- > drivers/usb/gadget/udc/core.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c > index 2dfae7a17b3f..81f9140f3681 100644 > --- a/drivers/usb/gadget/udc/core.c > +++ b/drivers/usb/gadget/udc/core.c > @@ -118,12 +118,10 @@ int usb_ep_enable(struct usb_ep *ep) > goto out; > > /* UDC drivers can't handle endpoints with maxpacket size 0 */ > - if (usb_endpoint_maxp(ep->desc) == 0) { > - /* > - * We should log an error message here, but we can't call > - * dev_err() because there's no way to find the gadget > - * given only ep. > - */ > + if (!ep->desc || usb_endpoint_maxp(ep->desc) == 0) { > + WARN_ONCE(1, "%s: ep%d (%s) has %s\n", __func__, ep->address, ep->name, > + (!ep->desc) ? "NULL descriptor" : "maxpacket 0"); So you just rebooted a machine that hit this, that's not good at all. Please log the error and recover, don't crash a system (remember, panic-on-warn is enabled in billions of Linux systems.) thanks, greg k-h