Re: [PATCH bpf-next] selftest/bpf: Switch recursion test to use htab_map_delete_elem
From: Song Liu <song@kernel.org>
Date: 2021-10-04 17:38:47
Also in:
bpf
On Sun, Oct 3, 2021 at 9:58 AM Jiri Olsa [off-list ref] wrote:
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>
Acked-by: Song Liu <redacted>
quoted hunk ↗ jump to hunk
--- tools/testing/selftests/bpf/prog_tests/recursion.c | 10 +++++----- tools/testing/selftests/bpf/progs/recursion.c | 9 +++------ 2 files changed, 8 insertions(+), 11 deletions(-)diff --git a/tools/testing/selftests/bpf/prog_tests/recursion.c b/tools/testing/selftests/bpf/prog_tests/recursion.c index 0e378d63fe18..f3af2627b599 100644 --- a/tools/testing/selftests/bpf/prog_tests/recursion.c +++ b/tools/testing/selftests/bpf/prog_tests/recursion.c@@ -20,18 +20,18 @@ void test_recursion(void) goto out; ASSERT_EQ(skel->bss->pass1, 0, "pass1 == 0"); - bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash1), &key, 0); + bpf_map_delete_elem(bpf_map__fd(skel->maps.hash1), &key); ASSERT_EQ(skel->bss->pass1, 1, "pass1 == 1"); - bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash1), &key, 0); + bpf_map_delete_elem(bpf_map__fd(skel->maps.hash1), &key); ASSERT_EQ(skel->bss->pass1, 2, "pass1 == 2"); ASSERT_EQ(skel->bss->pass2, 0, "pass2 == 0"); - bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash2), &key, 0); + bpf_map_delete_elem(bpf_map__fd(skel->maps.hash2), &key); ASSERT_EQ(skel->bss->pass2, 1, "pass2 == 1"); - bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash2), &key, 0); + bpf_map_delete_elem(bpf_map__fd(skel->maps.hash2), &key); ASSERT_EQ(skel->bss->pass2, 2, "pass2 == 2"); - err = bpf_obj_get_info_by_fd(bpf_program__fd(skel->progs.on_lookup), + err = bpf_obj_get_info_by_fd(bpf_program__fd(skel->progs.on_delete), &prog_info, &prog_info_len); if (!ASSERT_OK(err, "get_prog_info")) goto out;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; } --2.31.1