From: "Daniel T. Lee" <danieltimlee@gmail.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org
Subject: [bpf-next v4 3/3] samples/bpf: fix uninitialized warning with test_current_task_under_cgroup
Date: Sun, 18 Dec 2022 15:14:53 +0900 [thread overview]
Message-ID: <20221218061453.6287-4-danieltimlee@gmail.com> (raw)
In-Reply-To: <20221218061453.6287-1-danieltimlee@gmail.com>
Currently, compiling samples/bpf with LLVM warns about the uninitialized
use of variable with test_current_task_under_cgroup.
./samples/bpf/test_current_task_under_cgroup_user.c:57:6:
warning: variable 'cg2' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (setup_cgroup_environment())
^~~~~~~~~~~~~~~~~~~~~~~~~~
./samples/bpf/test_current_task_under_cgroup_user.c:106:8:
note: uninitialized use occurs here
close(cg2);
^~~
./samples/bpf/test_current_task_under_cgroup_user.c:57:2:
note: remove the 'if' if its condition is always false
if (setup_cgroup_environment())
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./samples/bpf/test_current_task_under_cgroup_user.c:19:9:
note: initialize the variable 'cg2' to silence this warning
int cg2, idx = 0, rc = 1;
^
= 0
1 warning generated.
This commit resolve this compiler warning by pre-initialize the variable
with error for safeguard.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
samples/bpf/test_current_task_under_cgroup_user.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/samples/bpf/test_current_task_under_cgroup_user.c b/samples/bpf/test_current_task_under_cgroup_user.c
index ac251a417f45..6fb25906835e 100644
--- a/samples/bpf/test_current_task_under_cgroup_user.c
+++ b/samples/bpf/test_current_task_under_cgroup_user.c
@@ -14,9 +14,9 @@
int main(int argc, char **argv)
{
pid_t remote_pid, local_pid = getpid();
+ int cg2 = -1, idx = 0, rc = 1;
struct bpf_link *link = NULL;
struct bpf_program *prog;
- int cg2, idx = 0, rc = 1;
struct bpf_object *obj;
char filename[256];
int map_fd[2];
@@ -103,7 +103,9 @@ int main(int argc, char **argv)
rc = 0;
err:
- close(cg2);
+ if (cg2 != -1)
+ close(cg2);
+
cleanup_cgroup_environment();
cleanup:
--
2.34.1
prev parent reply other threads:[~2022-12-18 6:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-18 6:14 [bpf-next v4 0/3] samples/bpf: fix LLVM compilation warning Daniel T. Lee
2022-12-18 6:14 ` [bpf-next v4 1/3] samples/bpf: remove unused function with test_lru_dist Daniel T. Lee
2022-12-18 6:14 ` [bpf-next v4 2/3] samples/bpf: replace meaningless counter with tracex4 Daniel T. Lee
2022-12-18 6:14 ` Daniel T. Lee [this message]
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