From: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Date: Sun, 9 Jan 2022 18:53:22 +0000 (+0100)
Subject: bpf: adjust comment about not calling sym_bpf_link__destroy
X-Git-Tag: v251-rc1~556^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d179b8d3683a38e1fa591b0079851ce2aff7d7dd;p=thirdparty%2Fsystemd.git

bpf: adjust comment about not calling sym_bpf_link__destroy
---

diff --git a/src/shared/bpf-link.c b/src/shared/bpf-link.c
index 85eab090328..fea49b2ecbb 100644
--- a/src/shared/bpf-link.c
+++ b/src/shared/bpf-link.c
@@ -32,12 +32,12 @@ int bpf_serialize_link(FILE *f, FDSet *fds, const char *key, struct bpf_link *li
 }
 
 struct bpf_link *bpf_link_free(struct bpf_link *link) {
-
-        /* Avoid a useless dlopen() if link == NULL */
-        if (!link)
-                return NULL;
-
-        (void) sym_bpf_link__destroy(link);
+        /* If libbpf wasn't dlopen()ed, sym_bpf_link__destroy might be unresolved (NULL), so let's not try to
+         * call it if link is NULL. link might also be a non-null "error pointer", but such a value can only
+         * originate from a call to libbpf, but that means that libbpf is available, and we can let
+         * bpf_link__destroy() handle it. */
+        if (link)
+                (void) sym_bpf_link__destroy(link);
 
         return NULL;
 }