On Thu, Dec 01, 2022 at 05:04:14PM -0800, Kees Cook wrote: > GCC 12 appears to perform constant propagation incompletely(?) and can > no longer notice that "len" is always 0 when "data" is NULL. Expand the > check to avoid warnings about memcpy() having a NULL argument: Is there a gcc option to turn off the "memcpy with NULL and len=0 is undefined behavior" thing? It's basically a bug in the C standard. Note that the kernel already uses options that make other types of undefined behavior defined: -fno-strict-overflow, -fno-strict-aliasing, and -fno-delete-null-pointer-checks. - Eric
