selftests/bpf: Fix trampoline_count clean up logic

Libbpf's Travis CI tests caught this issue. Ensure bpf_link and bpf_object
clean up is performed correctly.

Fixes: d633d57902a5 ("selftest/bpf: Add test for allowed trampolines count")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20200220230546.769250-1-andriin@fb.com

diff --git a/tools/testing/selftests/bpf/prog_tests/trampoline_count.c b/tools/testing/selftests/bpf/prog_tests/trampoline_count.c
index 1f6ccda..781c8d1 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/trampoline_count.c
+++ b/tools/testing/selftests/bpf/prog_tests/trampoline_count.c
@@ -55,31 +55,40 @@ void test_trampoline_count(void)
        /* attach 'allowed' 40 trampoline programs */
        for (i = 0; i < MAX_TRAMP_PROGS; i++) {
                obj = bpf_object__open_file(object, NULL);
-               if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj)))
+               if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) {
+                       obj = NULL;
                        goto cleanup;
+               }
 
                err = bpf_object__load(obj);
                if (CHECK(err, "obj_load", "err %d\n", err))
                        goto cleanup;
                inst[i].obj = obj;
+               obj = NULL;
 
                if (rand() % 2) {
-                       link = load(obj, fentry_name);
-                       if (CHECK(IS_ERR(link), "attach prog", "err %ld\n", PTR_ERR(link)))
+                       link = load(inst[i].obj, fentry_name);
+                       if (CHECK(IS_ERR(link), "attach prog", "err %ld\n", PTR_ERR(link))) {
+                               link = NULL;
                                goto cleanup;
+                       }
                        inst[i].link_fentry = link;
                } else {
-                       link = load(obj, fexit_name);
-                       if (CHECK(IS_ERR(link), "attach prog", "err %ld\n", PTR_ERR(link)))
+                       link = load(inst[i].obj, fexit_name);
+                       if (CHECK(IS_ERR(link), "attach prog", "err %ld\n", PTR_ERR(link))) {
+                               link = NULL;
                                goto cleanup;
+                       }
                        inst[i].link_fexit = link;
                }
        }
 
        /* and try 1 extra.. */
        obj = bpf_object__open_file(object, NULL);
-       if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj)))
+       if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) {
+               obj = NULL;
                goto cleanup;
+       }
 
        err = bpf_object__load(obj);
        if (CHECK(err, "obj_load", "err %d\n", err))
@@ -104,7 +113,9 @@ void test_trampoline_count(void)
 cleanup_extra:
        bpf_object__close(obj);
 cleanup:
-       while (--i) {
+       if (i >= MAX_TRAMP_PROGS)
+               i = MAX_TRAMP_PROGS - 1;
+       for (; i >= 0; i--) {
                bpf_link__destroy(inst[i].link_fentry);
                bpf_link__destroy(inst[i].link_fexit);
                bpf_object__close(inst[i].obj);