Re: [PATCH bpf-next V2 2/2] selftests/bpf: test_progs avoid minus shell exit codes

[Jesper Dangaard Brouer <brouer@redhat.com>]

On Mon, 6 Jul 2020 15:17:57 -0700
Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:

> On Mon, Jul 6, 2020 at 10:00 AM Jesper Dangaard Brouer
> <brouer@redhat.com> wrote:
> >
> > There are a number of places in test_progs that use minus-1 as the argument
> > to exit(). This improper use as a process exit status is masked to be a
> > number between 0 and 255 as defined in man exit(3).  
> 
> nit: I wouldn't call it improper use, as it's a well defined behavior
> (lower byte of returned integer).
> 
> >
> > This patch use two different positive exit codes instead, to allow a shell  
> 
> typo: uses
> 
> > script to tell the two error cases apart.
> >
> > Fixes: fd27b1835e70 ("selftests/bpf: Reset process and thread affinity after each test/sub-test")
> > Fixes: 811d7e375d08 ("bpf: selftests: Restore netns after each test")
> > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> > ---
> >  tools/testing/selftests/bpf/test_progs.c |   12 +++++++-----
> >  1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
> > index e8f7cd5dbae4..50803b080593 100644
> > --- a/tools/testing/selftests/bpf/test_progs.c
> > +++ b/tools/testing/selftests/bpf/test_progs.c
> > @@ -12,7 +12,9 @@
> >  #include <string.h>
> >  #include <execinfo.h> /* backtrace */
> >
> > -#define EXIT_NO_TEST 2
> > +#define EXIT_NO_TEST           2
> > +#define EXIT_ERR_NETNS         3
> > +#define EXIT_ERR_RESET_AFFINITY        4  
> 
> Let's not overdo this with too granular error codes? All of those seem
> to be just a failure, is there any practical need to differentiate
> between NETNS vs RESET_AFFINITY failure?

I agree, because both cases (NETNS vs RESET_AFFINITY) print to stderr,
which makes it possible to troubleshoot for a human afterwards.  The
shell script just need to differentiate that is an "infra" setup issue,
as we e.g. might want to allow the RPM build to continue in those cases.


> I'd go with 3 values:
> 
> 1 - at least one test failed
> 2 - no tests were selected
> 3 - "infra" (not a test-specific failure) error (like netns or affinity failed).
> 
> Thoughts?

Sure, I can do this.

What define name reflect this best:
 EXIT_ERR_SETUP ?
 EXIT_ERR_INFRA ?
 EXIT_ERR_SETUP_INFRA ?

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer