libbpf: fix memory leak in attach_tp for target-less tracepoint program

Fix sec_name memory leak if user defines target-less SEC("tp").

Fixes: 9af8efc45eb1 ("libbpf: Allow "incomplete" basic tracing SEC() definitions")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220516184547.3204674-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9aae886cbabfbd8a38a162e12272918960da3fb9..ef7f302e542f8ba1b8d2b7c7c860eaec47fa7315 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -11592,16 +11592,16 @@ static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_lin
 {
        char *sec_name, *tp_cat, *tp_name;
 
-       sec_name = strdup(prog->sec_name);
-       if (!sec_name)
-               return -ENOMEM;
-
        *link = NULL;
 
        /* no auto-attach for SEC("tp") or SEC("tracepoint") */
        if (strcmp(prog->sec_name, "tp") == 0 || strcmp(prog->sec_name, "tracepoint") == 0)
                return 0;
 
+       sec_name = strdup(prog->sec_name);
+       if (!sec_name)
+               return -ENOMEM;
+
        /* extract "tp/<category>/<name>" or "tracepoint/<category>/<name>" */
        if (str_has_pfx(prog->sec_name, "tp/"))
                tp_cat = sec_name + sizeof("tp/") - 1;