On Thu, Jan 12, 2017 at 09:27:47AM -0600, Benjamin Herrenschmidt wrote: > On Thu, 2017-01-12 at 11:30 +0100, Greg KH wrote: > > > > And don't call access_ok(), it's racy and no driver should ever do that. > > > > > > > > > > Oh, duly noted. I'll be sure to check out how and why. Perhaps it > > > would be wise that no driver actually do that, I'm quite sure I used > > > other drivers as examples of best practice. > > > > You did? Please point me at that code so we can fix them up properly. > > Cargo-cult coding is not a good thing, but it happens, so if we can at > > least provide clean code to fixate on, it's good overall for everyone. > > How so ? I mean, access_ok followed by __get/__put_user is still a > classic, what's wrong with it ? No "normal" driver should do that, just call copy_to/from_user and be done with it. That way all of the proper locking and validation checks like this are done correctly for you. Why would a driver ever call the "raw" __get/__put_user functions? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
