[PATCH] perf test bpf: Skip test if kernel-debuginfo is not present

[Arnaldo Carvalho de Melo]

Em Thu, Nov 03, 2022 at 12:27:01PM +0530, Athira Rajeev escreveu:
> > On 28-Oct-2022, at 9:12 PM, Kajol Jain <kjain at linux.ibm.com> wrote:
> > 
> > Perf BPF filter test fails in environment where "kernel-debuginfo"
> > is not installed.
> > 
> > Test failure logs:
> > <<>>
> > 42: BPF filter                            :
> > 42.1: Basic BPF filtering                 : Ok
> > 42.2: BPF pinning                         : Ok
> > 42.3: BPF prologue generation             : FAILED!
> > <<>>
> > 
> > Enabling verbose option provided debug logs, which says debuginfo
> > needs to be installed. Snippet of verbose logs:
> > 
> > <<>>
> > 42.3: BPF prologue generation                                       :
> > --- start ---
> > test child forked, pid 28218
> > <<>>
> > Rebuild with CONFIG_DEBUG_INFO=y, or install an appropriate debuginfo
> > package.
> > bpf_probe: failed to convert perf probe events
> > Failed to add events selected by BPF
> > test child finished with -1
> > ---- end ----
> > BPF filter subtest 3: FAILED!
> > <<>>
> > 
> > Here subtest, "BPF prologue generation" failed and
> > logs shows debuginfo is needed. After installing
> > kernel-debuginfo package, testcase passes.
> > 
> > Subtest "BPF prologue generation" failed because, the "do_test"
> > function returns "TEST_FAIL" without checking the error type
> > returned by "parse_events_load_bpf_obj" function.
> > Function parse_events_load_bpf_obj can also return error of type
> > "-ENOENT" incase kernel-debuginfo package is not installed. Fix this
> > by adding check for -ENOENT error.
> > 
> > Test result after the patch changes:
> > 
> > Test failure logs:
> > <<>>
> > 42: BPF filter                 :
> > 42.1: Basic BPF filtering      : Ok
> > 42.2: BPF pinning              : Ok
> > 42.3: BPF prologue generation  : Skip (clang/debuginfo isn't
> > installed or environment missing BPF support)
> > 
> > Fixes: ba1fae431e74bb42 ("perf test: Add 'perf test BPF'")
> > Signed-off-by: Kajol Jain <kjain at linux.ibm.com>
> > Reviewed-by: Madhavan Srinivasan <maddy at linux.ibm.com>
> > ---
> > tools/perf/tests/bpf.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
> > index 17c023823713..57cecadc1da2 100644
> > --- a/tools/perf/tests/bpf.c
> > +++ b/tools/perf/tests/bpf.c
> > @@ -126,6 +126,10 @@ static int do_test(struct bpf_object *obj, int (*func)(void),
> > 
> > 	err = parse_events_load_bpf_obj(&parse_state, &parse_state.list, obj, NULL);
> > 	parse_events_error__exit(&parse_error);
> > +	if (err == -ENOENT) {
> > +		pr_debug("Failed to add events selected by BPF, debuginfo package not installed\n");
> > +		return TEST_SKIP;
> > +	}
> 
> Hi Kajol,
> 
> Here, you have used ENOENT to skip the test. But there could be other places in the code path for “parse_events_load_bpf_obj”
> which also returns ENOENT. In that case, for any exit that returns ENOENT, test will get skipped.
> 
> Can we look at the logs, example we have this in commit logs:
> 
> 	Rebuild with CONFIG_DEBUG_INFO=y, or install an appropriate debuginfo
> 	package.
> 
> so as to decide whether to skip for debug info ?

Kajol?

- Arnaldo
 
> Thanks
> Athira
> 
> > 	if (err || list_empty(&parse_state.list)) {
> > 		pr_debug("Failed to add events selected by BPF\n");
> > 		return TEST_FAIL;
> > @@ -368,7 +372,7 @@ static struct test_case bpf_tests[] = {
> > 			"clang isn't installed or environment missing BPF support"),
> > #ifdef HAVE_BPF_PROLOGUE
> > 	TEST_CASE_REASON("BPF prologue generation", bpf_prologue_test,
> > -			"clang isn't installed or environment missing BPF support"),
> > +			"clang/debuginfo isn't installed or environment missing BPF support"),
> > #else
> > 	TEST_CASE_REASON("BPF prologue generation", bpf_prologue_test, "not compiled in"),
> > #endif
> > -- 
> > 2.31.1