Pádraig Brady wrote:
for UBSAN we should probably build with _STRING_ARCH_unaligned defined globally to avoid warning for the cases we already handle.
Yes. Translating this for non-experts: the problem here is a bug in the bug-finding procedure, not a bug in GNU coreutils or in Gnulib.
Recent glibc (since 2016-02-18) does not define _STRING_ARCH_unaligned, which means that this code in gnulib md5.c etc. is no longer exercised on recent platforms. So in some sense the originally-reported bug is already fixed (via an unexpected glibc change), though this does mean Gnulib md5 etc. is now slower on x86-64 etc., which is a performance bug on newer platforms. If we fix the performance bug I suppose we'll start getting false alarms from UBSAN again.
