On Wed, May 22, 2013 at 11:25:36AM +0200, Arnd Bergmann wrote: > Given the most commonly used functions and a couple of architectures > I'm familiar with, these are the ones that currently call might_fault() > > x86-32 x86-64 arm arm64 powerpc s390 generic > copy_to_user - x - - - x x > copy_from_user - x - - - x x > put_user x x x x x x x > get_user x x x x x x x > __copy_to_user x x - - x - - > __copy_from_user x x - - x - - > __put_user - - x - x - - > __get_user - - x - x - - > > WTF? I think your table is rather screwed - especially on ARM. Tell me - how can __copy_to_user() use might_fault() but copy_to_user() not when copy_to_user() is implemented using __copy_to_user() ? Same for copy_from_user() but the reverse argument - there's nothing special in our copy_from_user() which would make it do might_fault() when __copy_from_user() wouldn't. The correct position for ARM is: our (__)?(pu|ge)t_user all use might_fault(), but (__)?copy_(to|from)_user do not. Neither does (__)?clear_user. We might want to fix those to use might_fault(). -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>