Re: [PATCH] ubsan: fix tree-wide -Wmaybe-uninitialized false positives

From: Andrew Morton
Date: Mon Jan 25 2016 - 16:42:08 EST

On Mon, 25 Jan 2016 19:01:34 +0300 Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> wrote:

> -fsanitize=* options makes GCC less smart than usual and increase number
> of 'maybe-uninitialized' false-positives. So this patch does two things:
> * Add -Wno-maybe-uninitialized to CFLAGS_UBSAN which will disable all
> such warnings for instrumented files.
> * Remove CONFIG_UBSAN_SANITIZE_ALL from all[yes|mod]config builds. So
> the all[yes|mod]config build goes without -fsanitize=* and still with
> -Wmaybe-uninitialized.

hm, that's a bit sad.

We have no means of working out whether we should re-enable
maybe-uninitialized for later gcc's, as they become smarter about this.
What do we do, just "remember" to try it later on?

Do you know if this issue is on the gcc developer' radar?