Re: [PATCH] Driver core: fix race in __device_release_driver

From: Greg KH
Date: Fri Nov 16 2007 - 15:41:59 EST


On Fri, Nov 16, 2007 at 11:57:28AM -0500, Alan Stern wrote:
> This patch (as1013) was suggested by David Woodhouse; it fixes a race
> in the driver core. If a device is unregistered at the same time as
> its driver is unloaded, the driver's code pages may be unmapped while
> the remove method is still running. The calls to get_driver() and
> put_driver() were intended to prevent this, but they don't work if the
> driver's module count has already dropped to 0.
>
> Instead, the patch keeps the device on the driver's list until after
> the remove method has returned. This forces the necessary
> synchronization to occur.

Is this something that you all feel is worth getting in for 2.6.24?
Does it fix a regression that just showed up, or is just a bugfix for
something that people finally realized has always been there?

Can it wait for 2.6.25 to get some more testing in -mm?

thanks,

greg k-h
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