On Wed, Aug 19, 2020 at 8:19 AM Yonghong Song <yhs@xxxxxx> wrote: > > > > On 8/18/20 7:34 PM, Yauheni Kaliuta wrote: > > The error path in libbpf.c:load_program() has calls to pr_warn() > > which ends up for global_funcs tests to > > test_global_funcs.c:libbpf_debug_print(). > > > > For the tests with no struct test_def::err_str initialized with a > > string, it causes call of strstr() with NULL as the second argument > > and it segfaults. > > > > Fix it by calling strstr() only for non-NULL err_str. > > > > The patch does not fix the test itself. > > So this happens in older kernel, right? Could you clarify more > in which kernel and what environment? It probably no need to > fix the issue for really old kernel but some clarification > will be good. I'll test it with the very recent kernel on that architecture soon, for sure. But it's not related to the patch. > > > > > Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx> > > --- > > tools/testing/selftests/bpf/prog_tests/test_global_funcs.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c b/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c > > index 25b068591e9a..6ad14c5465eb 100644 > > --- a/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c > > +++ b/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c > > @@ -19,7 +19,7 @@ static int libbpf_debug_print(enum libbpf_print_level level, > > log_buf = va_arg(args, char *); > > if (!log_buf) > > goto out; > > - if (strstr(log_buf, err_str) == 0) > > + if ((err_str != NULL) && (strstr(log_buf, err_str) == 0)) > > Looks good but the code can be simplified as > if (err_str && strstr(log_buf, err_str) == 0) > found = true; Yes, but I prefer to use NULL explicitly when I deal with pointers. It demonstrates intention better. You also can simplify strstr() == 0 with !. Actually, strstr() returns char *, so comparation to 0 (totally legal by standard) breaks my feelings too :). If you insist, I'll send v2 of course. > > found = true; > > out: > > printf(format, log_buf); > > > -- WBR, Yauheni
