From: "Maxime Villard" <m...@netbsd.org> Date: Wed, 16 Apr 2014 18:55:20 +0000
An (un)privileged user can easily make the kernel dereference a NULL pointer. The kernel allows 'data' to be NULL; it's the fs's responsibility to ensure that it isn't NULL (if the fs actually needs data). In most cases of the changes you made, there is already a test for the length of the data buffer. Is this not guaranteed to be zero if data is null? It seems to me that the length test ought to suffice, and if anything the null pointer test should be an assertion, not a check.