Messages in this thread | | | Date | Wed, 26 Sep 2012 13:36:26 -0700 | From | Greg Kroah-Hartman <> | Subject | Re: [BUG] Deferred probing in driver model is racy, resulting in lost probes |
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On Wed, Sep 26, 2012 at 09:23:21PM +0100, Russell King - ARM Linux wrote: > On Wed, Sep 26, 2012 at 01:08:33PM -0700, Greg Kroah-Hartman wrote: > > On Sun, Sep 16, 2012 at 09:24:43PM +0800, Ming Lei wrote: > > > diff --git a/drivers/base/bus.c b/drivers/base/bus.c > > > index 181ed26..17d7437 100644 > > > --- a/drivers/base/bus.c > > > +++ b/drivers/base/bus.c > > > @@ -714,12 +714,12 @@ int bus_add_driver(struct device_driver *drv) > > > if (error) > > > goto out_unregister; > > > > > > + klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers); > > > if (drv->bus->p->drivers_autoprobe) { > > > error = driver_attach(drv); > > > if (error) > > > goto out_unregister; > > > } > > > - klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers); > > > module_add_driver(drv->owner, drv); > > > > > > error = driver_create_file(drv, &driver_attr_uevent); > > > > > > > > > > > > > Did the above patch ever prove to solve the issue or not? > > To be honest, I've not bothered to test the above patch, and now when I > look at it, I notice it's broken - in that on error it will corrupt the > driver list. Take a look at the error path. > > priv is drv->p. We add priv->knode_bus to the driver list. If > driver_attach() returns an error, then we go to out_unregister, which > does: > > out_unregister: > kobject_put(&priv->kobj); > kfree(drv->p); > drv->p = NULL; > > thereby freeing the node we just added to the driver list without first > removing it. > > I suspect it will fix the problem, but let's get the patch to be correct > before it gets tested...
Good catch. Ming, care to redo this?
greg k-h
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