[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20241022172329.3871958-3-ezulian@redhat.com>
Date: Tue, 22 Oct 2024 19:23:28 +0200
From: Eder Zulian <ezulian@...hat.com>
To: bpf@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: ast@...nel.org,
daniel@...earbox.net,
andrii@...nel.org,
martin.lau@...ux.dev,
eddyz87@...il.com,
song@...nel.org,
yonghong.song@...ux.dev,
john.fastabend@...il.com,
kpsingh@...nel.org,
sdf@...ichev.me,
haoluo@...gle.com,
jolsa@...nel.org,
acme@...hat.com,
vmalik@...hat.com,
williams@...hat.com
Subject: [PATCH v2 2/3] libbpf: Prevent compiler warnings/errors
Initialize 'new_off' and 'pad_bits' to 0 and 'pad_type' to NULL in
btf_dump_emit_bit_padding to prevent compiler warnings/errors which are
observed when compiling with 'EXTRA_CFLAGS=-g -Og' options, but do not
happen when compiling with current default options.
For example, when compiling libbpf with
$ make "EXTRA_CFLAGS=-g -Og" -C tools/lib/bpf/ clean all
Clang version 17.0.6 and GCC 13.3.1 fail to compile btf_dump.c due to
following errors:
btf_dump.c: In function ‘btf_dump_emit_bit_padding’:
btf_dump.c:903:42: error: ‘new_off’ may be used uninitialized [-Werror=maybe-uninitialized]
903 | if (new_off > cur_off && new_off <= next_off) {
| ~~~~~~~~^~~~~~~~~~~
btf_dump.c:870:13: note: ‘new_off’ was declared here
870 | int new_off, pad_bits, bits, i;
| ^~~~~~~
btf_dump.c:917:25: error: ‘pad_type’ may be used uninitialized [-Werror=maybe-uninitialized]
917 | btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
918 | in_bitfield ? new_off - cur_off : 0);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
btf_dump.c:871:21: note: ‘pad_type’ was declared here
871 | const char *pad_type;
| ^~~~~~~~
btf_dump.c:930:20: error: ‘pad_bits’ may be used uninitialized [-Werror=maybe-uninitialized]
930 | if (bits == pad_bits) {
| ^
btf_dump.c:870:22: note: ‘pad_bits’ was declared here
870 | int new_off, pad_bits, bits, i;
| ^~~~~~~~
cc1: all warnings being treated as errors
Signed-off-by: Eder Zulian <ezulian@...hat.com>
---
tools/lib/bpf/btf_dump.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 8440c2c5ad3e..468392f9882d 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -867,8 +867,8 @@ static void btf_dump_emit_bit_padding(const struct btf_dump *d,
} pads[] = {
{"long", d->ptr_sz * 8}, {"int", 32}, {"short", 16}, {"char", 8}
};
- int new_off, pad_bits, bits, i;
- const char *pad_type;
+ int new_off = 0, pad_bits = 0, bits, i;
+ const char *pad_type = NULL;
if (cur_off >= next_off)
return; /* no gap */
--
2.46.2
Powered by blists - more mailing lists