On Thu, Jun 13, 2019 at 09:44:46PM -0300, Jason Gunthorpe wrote: > From: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > > No other register/unregister kernel API attempts to provide this kind of > protection as it is inherently racy, so just drop it. > > Callers should provide their own protection, it appears nouveau already > does, but just in case drop a debugging POISON. I don't even think we even need to bother with the POISON, normal list debugging will already catch a double unregistration anyway. Otherwise looks fine: Reviewed-by: Christoph Hellwig <hch@xxxxxx>