> The trouble was that in that context, a null pointer dereference didn't trap, (because it was kernel code? not sure.) so the bug was not detected. Yes, becau

> The trouble was that in that context, a null pointer dereference didn't trap, (because it was kernel code? not sure.) so the bug was not detected. Yes, because it was kernel code. Because that dereference is completely legal in kernel code. The C code was fine, assuming that it was compiled with appropriate kernel flags. This was not a bug in Linux, at least not on the level of the C code itself. > The linux kernel now uses -fno-delete-null-pointer-checks to ensure that doesn't happen again. I also seem to remember that it was already using other "please compile this as kernel code" flags that should have implied "no-delete-null-pointer-checks" behavior, and that the lack of this implication was considered a bug in GCC and fixed.