Messages in this thread | | | Date | Tue, 02 Aug 2022 21:59:05 +0530 | From | Siddh Raman Pant <> | Subject | Re: [PATCH] x86/numa: Use cpumask_available instead of hardcoded NULL check |
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On Tue, 02 Aug 2022 16:37:44 +0530 Ingo Molnar <mingo@kernel.org> 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.)
The config on which I can reproduce the warning can be found here: https://gist.github.com/siddhpant/0197ea2b9873e8719d5d7ef991e2cd89 (It has 8969 lines, thus uploaded as a gist.)
This is a modification of a config found on syzkaller, which I was using to compile and test some bug. I had noticed the gcc warning earlier while on similar detours and usually ignored it, but now I finally took a look.
I tested compiling with it 5 times (`make clean` and `make -j13 all`), and gcc gave the warning in all attempts. I also tried `make -j1 all`, which also had gcc spitting out the warning, so it cannot be any race.
> > Fixes: c032ef60d1aa ("cpumask: convert node_to_cpumask_map[] to cpumask_var_t") > > Fixes: de2d9445f162 ("x86: Unify node_to_cpumask_map handling between 32 and 64bit") > > These are ancient commits from 2009 & 2011.
Yes, that's where blaming the file leads me to.
Thanks, Siddh
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