From: Tony Ambardar <tony.ambardar@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: Tony Ambardar <Tony.Ambardar@gmail.com>,
Andrii Nakryiko <andriin@fb.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH bpf v1] libbpf: fix build failure from uninitialized variable warning
Date: Sun, 30 Aug 2020 17:03:04 -0700 [thread overview]
Message-ID: <20200831000304.1696435-1-Tony.Ambardar@gmail.com> (raw)
While compiling libbpf, some GCC versions (at least 8.4.0) have difficulty
determining control flow and a emit warning for potentially uninitialized
usage of 'map', which results in a build error if using "-Werror":
In file included from libbpf.c:56:
libbpf.c: In function '__bpf_object__open':
libbpf_internal.h:59:2: warning: 'map' may be used uninitialized in this function [-Wmaybe-uninitialized]
libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
^~~~~~~~~~~~
libbpf.c:5032:18: note: 'map' was declared here
struct bpf_map *map, *targ_map;
^~~
The warning/error is false based on code inspection, so silence it with a
NULL initialization.
Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support")
Ref: 063e68813391 ("libbpf: Fix false uninitialized variable warning")
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
---
tools/lib/bpf/libbpf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b688aadf09c5..46d727b45c81 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5804,8 +5804,8 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
int i, j, nrels, new_sz;
const struct btf_var_secinfo *vi = NULL;
const struct btf_type *sec, *var, *def;
+ struct bpf_map *map = NULL, *targ_map;
const struct btf_member *member;
- struct bpf_map *map, *targ_map;
const char *name, *mname;
Elf_Data *symbols;
unsigned int moff;
--
2.25.1
next reply other threads:[~2020-08-31 0:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 0:03 Tony Ambardar [this message]
2020-08-31 14:59 ` [PATCH bpf v1] libbpf: fix build failure from uninitialized variable warning Daniel Borkmann
2020-09-02 7:39 ` Tony Ambardar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200831000304.1696435-1-Tony.Ambardar@gmail.com \
--to=tony.ambardar@gmail.com \
--cc=andriin@fb.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).