RE: mcs7830 usb net: "scheduling while atomic" danger?
From: Julia Lawall
Date: Tue Jan 19 2010 - 01:26:14 EST
So you will fix /var/linuxes/linux-next/drivers/usb/host/ehci-hub.c?
I think it is a bit out of my expertise...
On Tue, 19 Jan 2010, Du, Alek wrote:
> I confirm that thing is bad, I need to prepare another patch to fix that.
> >-----Original Message-----
> >From: Arnd Bergmann [mailto:arnd@xxxxxxxx]
> >Sent: Tuesday, January 19, 2010 5:24 AM
> >To: Julia Lawall
> >Cc: Andreas Mohr; linux-kernel@xxxxxxxxxxxxxxx; Greg KH; Du, Alek; Pan, Jacob
> >jun; Alan Stern
> >Subject: Re: mcs7830 usb net: "scheduling while atomic" danger?
> >On Monday 18 January 2010, Julia Lawall wrote:
> >> On Mon, 18 Jan 2010, Andreas Mohr wrote:
> >> >
> >> > Forgive me, but doesn't that mutex_lock()/msleep() (ab)use mean
> >> > risking a "scheduling while atomic"?
> >> > (such as discussed in e.g.
> >> > http://search.luky.org/linux-kernel.2004/msg92817.html )
> >> >
> >> >
> >> > And, if that is the case, shouldn't all such cases simply be killed for
> >> > good via a capable semantic patch?
> >> The semantic match shown below finds 55 matches. All but two involve
> >> mutex_lock. Those are in the file
> >> /var/linuxes/linux-next/drivers/usb/host/ehci-hub.c
> >> in the functions ehci_bus_suspend and ehci_hub_control.
> >That code looks indeed broken as was added las July as part of 331ac6b288d9
> >"USB: EHCI: Add Intel Moorestown EHCI controller HOSTPCx extensions and
> >support phy low power mode". The reason that this hasn't triggered is
> >probably the lack of Moorestown machines in the field.
> > Arnd
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