Re: [PATCH] m68k: fix assembler constraint to prevent overeager gcc optimisation

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On Sun, Jan 22, 2012 at 11:15, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
On Mon, Jan 9, 2012 at 15:10, Andreas Schwab <schwab@xxxxxxxxxxxxxx> wrote:
Passing the address of a variable as an operand to an asm statement
doesn't mark the value of this variable as used, so gcc may optimize its
initialisation away.  Fix this by using the "m" constraint instead.

Thanks! I'll apply and queue for -stable.

BTW, is it reasonable to assume we never saw the problem before because
there used to be a set_fs() call in flush_thread()?
Cfr. commit b7de110044b4e26adcb7b278d14da93133692ed7 ("m68k, exec:
remove redundant set_fs(USER_DS)"),
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=b7de110044b4e26adcb7b278d14da93133692ed7

That would mean it happens in 3.1 and later only.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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