Re: [PATCH] x86: BUILD_IRQ say .text to avoid .data.percpu

From: Ingo Molnar
Date: Thu Jul 24 2008 - 06:45:33 EST



* Hugh Dickins <hugh@xxxxxxxxxxx> wrote:

> When I edit the x86_64 Makefile to -fno-unit-at-a-time, bootup panics
> on 0xCCs in IRQ0x3e_interrupt(): IRQ0x20_interrupt etc. have got linked
> into .data.percpu. Perhaps there are other ways of triggering that:
> specify ".text" in the BUILD_IRQ() macro for safety.
>
> Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>

applied to tip/x86/urgent, thanks Hugh.

> I've been using -fno-unit-at-a-time (to lessen inlining, for easier
> debugging) for a long time, but never saw this until Mike's percpu
> mods came in: I mention this so you're on the lookout, just in case
> other things are more likely to go into the wrong section now. (I did
> give Mike a private headsup on this a couple of weeks ago, in case it
> helped with problems he was having with percpu, but in fact it didn't
> help.)

Should we perhaps enable this automatically on CONFIG_FRAME_POINTER=y
builds? Although a separate, default-off config option might be better,
i'd not be surprised if there were more regressions in this area, it's a
seldom used build vector.

Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/