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SubjectRe: [PATCH] platform_driver_register: warn if probe is in .init.text
Hi Greg,

On Fri, Jun 19, 2009 at 04:43:54PM +0200, Uwe Kleine-König wrote:
> On Fri, Jun 19, 2009 at 07:11:28AM -0700, Greg KH wrote:
> > On Fri, Jun 19, 2009 at 03:42:19PM +0200, Uwe Kleine-König wrote:
> > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > > ---
> > > drivers/base/platform.c | 42 ++++++++++++++++++++++++++++++++++++------
> > > include/linux/kernel.h | 2 ++
> > > include/linux/module.h | 12 ++++++++++++
> > > kernel/extable.c | 12 ++++++++++++
> > > kernel/module.c | 36 ++++++++++++++++++++++++++++++++++++
> > > 5 files changed, 98 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> > > index 81cb01b..851ba84 100644
> > > --- a/drivers/base/platform.c
> > > +++ b/drivers/base/platform.c
> > > @@ -470,11 +470,7 @@ static void platform_drv_shutdown(struct device *_dev)
> > > drv->shutdown(dev);
> > > }
> > >
> > > -/**
> > > - * platform_driver_register
> > > - * @drv: platform driver structure
> > > - */
> > > -int platform_driver_register(struct platform_driver *drv)
> > > +static int __platform_driver_register(struct platform_driver *drv)
> > > {
> > > drv->driver.bus = &platform_bus_type;
> > > if (drv->probe)
> > > @@ -489,6 +485,40 @@ int platform_driver_register(struct platform_driver *drv)
> > >
> > > return driver_register(&drv->driver);
> > > }
> > > +
> > > +/**
> > > + * platform_driver_register
> > > + * @drv: platform driver structure
> > > + */
> > > +int platform_driver_register(struct platform_driver *drv)
> > > +{
> > > + int ret = __platform_driver_register(drv);
> > > +
> > > +#if defined(CONFIG_HOTPLUG)
> > > + /*
> > > + * drivers that are registered by platform_driver_register
> > > + * should not have their probe function in .init.text. The
> > > + * reason is that a probe can happen after .init.text is
> > > + * discarded which then results in an oops. The alternatives
> > > + * are using .devinit.text for the probe function or "register"
> > > + * with platform_driver_probe.
> > > + */
> >
> > That's not true, remember, drivers built into the system, like platform
> > ones, can have their probe function in .init.text, as it will be called
> > before we discard .init.text, and will never be called again as the
> > device will never be "hot added" at any future time.
> >
> > So this could trigger a lot of false positives :(
> IMHO this is not a false positive. You can still do
>
> for f in unbind bind do echo $deviceid > /sys/bus/platform/drivers/$drivername/$f; done
>
> This type of driver should use platform_driver_probe.
Are you conviced and took the patch or did you give up to convince me?

I still think the patch is correct and I'd like to have it applied.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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