Re: [PATCH] x86/numa: Use cpumask_available instead of hardcoded NULL check

From: Ingo Molnar
Date: Wed Aug 03 2022 - 04:48:29 EST



* Siddh Raman Pant <code@xxxxxxxx> wrote:

> On Tue, 02 Aug 2022 16:37:44 +0530 Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> > Your fix makes sense I suppose, but I'm wondering how testing didn't
> > trigger this warning.
> >
> > Off-stack isn't a rare config option:
> >
> > kepler:~/tip> make allmodconfig
> > #
> > # No change to .config
> > #
> > kepler:~/tip> grep CPUMASK_OFFSTACK .config
> > CONFIG_CPUMASK_OFFSTACK=y
> > kepler:~/tip>
> >
> > What am I missing?
>
> Maybe this triggers on certain config options set, or maybe due to new
> gcc version? (I'm using gcc-12, I also likely saw while on gcc-11.)
> It nevertheless is a helpful warning.
>
> I just now tried `make defconfig` (default configuration based on
> 'x86_64_defconfig') and compiling with `make -j13 all`, and gcc doesn't
> give any warning. (CONFIG_CPUMASK_OFFSTACK isn't even listed in the
> .config file produced, grep fails.)

Does 'allmodconfig' reproduce the warning for you:

$ make allmodconfig
$ make arch/x86/mm/numa.o

?

If yes, then this could be due to gcc-12, as it doesn't reproduce with
gcc-11 for me:

gcc version 11.2.0 (Ubuntu 11.2.0-19ubuntu1)

Thanks,

Ingo