Re: [PATCH] sched/all: Change BUG_ON() instances to WARN_ON()

Jason Gunthorpe
2022-08-11T23:23:02Z

On Thu, Aug 11, 2022 at 10:28:27PM +0100, Matthew Wilcox wrote:
> On Thu, Aug 11, 2022 at 01:43:09PM -0700, Linus Torvalds wrote:
> > May I suggest going one step further, and making these WARN_ON_ONCE() instead.
> >
> > >From personal experience, once some scheduler bug (or task struct
> > corruption) happens, ti often *keeps* happening, and the logs just
> > fill up with more and more data, to the point where you lose sight of
> > the original report (and the machine can even get unusable just from
> > the logging).
>
> I've been thinking about magically turning all the WARN_ON_ONCE() into
> (effectively) WARN_ON_RATELIMIT(). I had some patches in that direction
> a while ago but never got round to tidying them up for submission.

I often wonder if we have a justification for WARN_ON to even exist, I
see a lot of pressure to make things into WARN_ON_ONCE based on the
logic that spamming makes it useless..

Maybe a global limit of 10 warn ons per minute or something would be
interesting?

Jason