Sorry I realise it's version 7, but although the above looks correct it's
kind of dense.

I think the below would also work and is (I think) easier to follow, and
is more obviously similar to the existing code. I'm sure your version is
faster, but I don't think it's that performance critical.

static void dedotify_ext_version_names(char *str_seq, unsigned long size)
{
        char *end = str_seq + size;
        char *p = str_seq;

        while (p < end) {
                if (*p == '.')
                        memmove(p, p + 1, end - p - 1);

                p += strlen(p) + 1;
        }
}

The tail of str_seq will be filled with nulls as long as the last string
was null terminated.

cheers

As you alluded to, what you're providing is potentially O(n^2) in the
number of symbols a module depends on - the existing code is O(n).
If leading dots on names are rare, this is probably fine. If they're
common, this will potentially make loading modules with a large number
of imported symbols actually take a measurable amount of additional
time.

That said, I take your point about complexity, and trust you to know
your arch's inputs/requirements, so if I don't hear back again I will
incorporate that into the next revision of the patch (to be produced
after the gendwarfksyms update comes out).