linux-kernel - Re: [PATCH/RFC] usb: fix renesas_usbhs to not schedule in atomic context

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20120206103158.GK15652@legolas.emea.dhcp.ti.com>
Date:	Mon, 6 Feb 2012 12:31:59 +0200
From:	Felipe Balbi <balbi@...com>
To:	Guennadi Liakhovetski <g.liakhovetski@....de>
Cc:	Felipe Balbi <balbi@...com>,
	"Shimoda, Yoshihiro" <yoshihiro.shimoda.uh@...esas.com>,
	linux-kernel@...r.kernel.org, linux-sh@...r.kernel.org,
	Vinod Koul <vinod.koul@...el.com>,
	Magnus Damm <magnus.damm@...il.com>, linux-mmc@...r.kernel.org,
	alsa-devel@...a-project.org, linux-serial@...r.kernel.org,
	Paul Mundt <lethal@...ux-sh.org>, linux-usb@...r.kernel.org
Subject: Re: [PATCH/RFC] usb: fix renesas_usbhs to not schedule in atomic
 context

Hi,

On Mon, Feb 06, 2012 at 11:11:45AM +0100, Guennadi Liakhovetski wrote:
> Hi Felipe
> 
> On Sun, 5 Feb 2012, Felipe Balbi wrote:
> 
> > Hi,
> > 
> > On Fri, Feb 03, 2012 at 04:43:20PM +0100, Guennadi Liakhovetski wrote:
> > > The current renesas_usbhs driver triggers
> > > 
> > > BUG: scheduling while atomic: ksoftirqd/0/3/0x00000102
> > > 
> > > with enabled CONFIG_DEBUG_ATOMIC_SLEEP, by submitting DMA transfers from 
> > > an atomic (tasklet) context, which is not supported by the shdma dmaengine 
> > > driver. Fix it by switching to a work. Also simplify some list 
> > > manipulations.
> > 
> > you are doing much more than what you say.
> 
> Are those two list macro changes what you refer to as "a lot?" ;-) You're 
> right in principle, they are not directly related to the purpose of this 
> patch, they are just something that occurred to me, while tracking down 
> DMA packets. But yes, it can be extracted to a separate cosmetic patch...

please do so ;-)

> > Also, instead of using a
> > workqueue, have you considered using threaded_irqs ?
> > 
> > (I didn't go over the driver again to see if it makes sense to use
> > threaded_irqs in this case, but doesn't hurt asking)
> 
> From a first glance these tasklets are not directly enough related to 
> IRQs, so, doing that is either impossible, or would require a _much_ 
> deeper change to the driver and _this_ would indeed be a much bigger 
> change than just fixing the Oops.

I see.. so please just split the list changes to separate patch and
resend.

-- 
balbi

Download attachment "signature.asc" of type "application/pgp-signature" (837 bytes)