Yes, there's no good excuse for the kernel failing to ignore what is clearly whitespace. Someone please fix Linux already. This bug has existed for way too long.

( And how come it seems that there aren't any Linux users that know that she-bang lines are handled by the kernel? I think that change even predates Linux so there never was a Linux where the shell had to do the #!-handling. How many decades does it take for people to catch on? :)

Interestingly, the kernel code in question (C, not perl I'm afraid :-) already does this:

    while (cp > bprm->buf) {
        cp--;
        if ((*cp == ' ') || (*cp == '\t'))
            *cp = '\0';
        else
            break;
    }
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i.e. it finished the executable name at the first space or tab. I guess a better patch would be to change that if test to also null out '\r' (hmm...and probably form-feed and others whilst we're at it).

I wonder how loudly people would scream if this were proposed as a kosher kernel patch. It breaks backwards compatability quite badly, but perhaps only for people who deserve it...

Just change that to:

  if (isspace(*cp))
    *cp = '\0';
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Don't forget to #include <linux/ctype.h> up top, though, to get this macro...

When I first started with openbsd and freebsd 6 years ago I assumed the shell was responsible for the shebang, and never revisited the topic to challenge that assumption. It was never quite important enough for me to research it.