Jeffrey Walton <[email protected]> writes: > On Tue, Dec 2, 2025 at 4:56 PM Bruno Haible via Gnulib discussion list > <[email protected]> wrote: >> >> I wrote: >> > The buggy commit is FreeBSD commit >> > e19d46c808267f53455e96a28ff7654211523d2c. >> >> One can also say that the buggy commit is >> 90253d49db09a9b1490c448d05314f3e4bbfa468. >> >> The reproducer crashes at the instruction >> movdqa 0x10(%rsi),%xmm0 >> at line 230 of src/lib/libc/amd64/string/stpncpy.S. > > If the code is changed from an aligned load (movdqa) to a non-aligned > load (movdqu), the problem will likely go away. It is easier than > trying to get the compiler to use a non-aligned string with fixups and > casts. > > In the old days there might be a small performance gain by using > aligned words and movdqa. Nowaday it is not worth it for most cases.
According to the author of that code it is an off-by-one error [1]. Collin [1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=291359#c2
