[RFC] drm/tests: annotate intentional stack trace in drm_test_rect_calc_hscale()

[Dan Carpenter]

On Mon, Nov 06, 2023 at 02:58:12PM +0100, mripard at kernel.org wrote:
> > But a similar thing is happening here where we have so many bogus
> > warnings that we missed a real bug.
> 
> IIRC, there was a similar discussion for lockdep issues. IMO, any
> (unintended) warning should trigger a test failure.
> 
> I guess that would require adding some intrumentation to __WARN somehow,
> and also allowing tests to check whether a warning had been generated
> during their execution for tests that want to trigger one.

I think this is a good idea.  I was looking at how lockdep prints
warnings (see print_circular_bug_header()).  It doesn't use WARN() it
prints a bunch of pr_warn() statements and then a stack trace.  We would
have to have a increment the counter manually in that situation.

I'm writing a script to parse a dmesg and collect Oopses.  So now I know
to look for WARN(), lockdep, and KASAN.  What other bugs formats do we
have?  Probably someone like the syzbot devs have already has written a
script like this?

regards,
dan carpenter