>> It is probably clear that the function call “kfree(NULL)” does not perform >> data processing which is really useful for the caller. >> Such a call is kept in some cases because programmers did not like to invest >> development resources for its avoidance. > > on the contrary, it is extremely useful for callers to not have to perform > the NULL check themselves. Some function calls indicate a resource allocation failure by a null pointer. Such pointer checks are generally performed for error detection so that appropriate exception handling can be chosen. > It also mirrors userspace where free(NULL) > is valid according to ISO/ANSI C, so eases the transition for programmers > who are coming from userspace. It costs nothing in the implementation > as it is part of the check for the ZERO_PTR. How many development efforts do you dare to spend on more complete and efficient error/exception handling? Regards, Markus
