selftest/bpf: Switch recursion test to use htab_map_delete_elem

Currently the recursion test is hooking __htab_map_lookup_elem
function, which is invoked both from bpf_prog and bpf syscall.

But in our kernel build, the __htab_map_lookup_elem gets inlined
within the htab_map_lookup_elem, so it's not trigered and the
test fails.

Fixing this by using htab_map_delete_elem, which is not inlined
for bpf_prog calls (like htab_map_lookup_elem is) and is used
directly as pointer for map_delete_elem, so it won't disappear
by inlining.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/YVnfFTL/3T6jOwHI@krava

1 files changed, 3 insertions, 6 deletions

diff --git a/tools/testing/selftests/bpf/progs/recursion.c b/tools/testing/selftests/bpf/progs/recursion.c
index 49f679375b9d..3c2423bb19e2 100644
--- a/tools/testing/selftests/bpf/progs/recursion.c
+++ b/tools/testing/selftests/bpf/progs/recursion.c
@@ -24,8 +24,8 @@ struct {
 int pass1 = 0;
 int pass2 = 0;
 
-SEC("fentry/__htab_map_lookup_elem")
-int BPF_PROG(on_lookup, struct bpf_map *map)
+SEC("fentry/htab_map_delete_elem")
+int BPF_PROG(on_delete, struct bpf_map *map)
 {
 	int key = 0;
 
@@ -35,10 +35,7 @@ int BPF_PROG(on_lookup, struct bpf_map *map)
 	}
 	if (map == (void *)&hash2) {
 		pass2++;
-		/* htab_map_gen_lookup() will inline below call
-		 * into direct call to __htab_map_lookup_elem()
-		 */
-		bpf_map_lookup_elem(&hash2, &key);
+		bpf_map_delete_elem(&hash2, &key);
 		return 0;
 	}