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

[Athira Rajeev]

> 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 ?

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
>