Re: linux-next: build failure after merge of the tip tree

Will Deacon
2020-05-21T17:35:28Z

Hi Stephen,

[+Marco and Boris]

On Fri, May 22, 2020 at 03:31:19AM +1000, Stephen Rothwell wrote:
> After merging the tip tree, all my linux-next builds took signficantly
> longer and used much more memory. In some cases, builds would seg fault
> due to running out of memory :-(
>
> I have eventaully bisected it to commit
>
> cdd28ad2d811 ("READ_ONCE: Use data_race() to avoid KCSAN instrumentation")
>
> For my (e.g.) x86_64 allmodconfig builds (cross compiled on PowerPC le,
> -j80) the elapsed time went from around 9 minutes to over 17 minutes
> and the maximum resident size (as reported by /usr/bin/time) from around
> 500M to around 2G (I saw lots of cc1 processes over 2G in size).
>
> For tomorrow's linux-next (well, later today :-() I will revert that
> commit (and its child) when I merge the tip tree.

Sorry about that, seems we can't avoid running into compiler problems with
this lot. The good news is that there's a series to fix this here:

https://lore.kernel.org/r/20200521142047.169334-1-elver@google.com

so hopefully this be fixed in -tip soon (but I agree that reverting the
thing in -next in the meantime makes sense).

Will