diff options
| -rw-r--r-- | tools/lib/bpf/linker.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index d7069780984a..5ced96d99f8c 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -1115,7 +1115,19 @@ static int extend_sec(struct bpf_linker *linker, struct dst_sec *dst, struct src if (src->shdr->sh_type != SHT_NOBITS) { tmp = realloc(dst->raw_data, dst_final_sz); - if (!tmp) + /* If dst_align_sz == 0, realloc() behaves in a special way: + * 1. When dst->raw_data is NULL it returns: + * "either NULL or a pointer suitable to be passed to free()" [1]. + * 2. When dst->raw_data is not-NULL it frees dst->raw_data and returns NULL, + * thus invalidating any "pointer suitable to be passed to free()" obtained + * at step (1). + * + * The dst_align_sz > 0 check avoids error exit after (2), otherwise + * dst->raw_data would be freed again in bpf_linker__free(). + * + * [1] man 3 realloc + */ + if (!tmp && dst_align_sz > 0) return -ENOMEM; dst->raw_data = tmp; |