[PATCH] selftests: cgroup: Fix unsigned expression compared with zero

[PATCH] selftests: cgroup: Fix unsigned expression compared with zero

[Jiapeng Chong]

Fix the following coccicheck warnings:

./tools/testing/selftests/cgroup/cgroup_util.c:566:8-12: WARNING:
Unsigned expression compared with zero: size < 0.

Reported-by: Abaci Robot <abaci-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Signed-off-by: Jiapeng Chong <jiapeng.chong-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
---
 tools/testing/selftests/cgroup/cgroup_util.c | 2 +-
 tools/testing/selftests/cgroup/cgroup_util.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 4c52cc6f2f9c..661e06b94a43 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -552,7 +552,7 @@ int proc_mount_contains(const char *option)
 	return strstr(buf, option) != NULL;
 }
 
-ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size)
+ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, ssize_t size)
 {
 	char path[PATH_MAX];
 
diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
index c92df4e5d395..7b3865805f50 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.h
+++ b/tools/testing/selftests/cgroup/cgroup_util.h
@@ -53,7 +53,7 @@ extern int set_oom_adj_score(int pid, int score);
 extern int cg_wait_for_proc_count(const char *cgroup, int count);
 extern int cg_killall(const char *cgroup);
 int proc_mount_contains(const char *option);
-extern ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size);
+extern ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, ssize_t size);
 extern int proc_read_strstr(int pid, bool thread, const char *item, const char *needle);
 extern pid_t clone_into_cgroup(int cgroup_fd);
 extern int clone_reap(pid_t pid, int options);
-- 
2.20.1.7.g153144c

Re: [PATCH] selftests: cgroup: Fix unsigned expression compared with zero

[Tejun Heo]

On Wed, Apr 27, 2022 at 02:17:56PM +0800, Jiapeng Chong wrote:
> Fix the following coccicheck warnings:
> 
> ./tools/testing/selftests/cgroup/cgroup_util.c:566:8-12: WARNING:
> Unsigned expression compared with zero: size < 0.
> 
> Reported-by: Abaci Robot <abaci-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
> Signed-off-by: Jiapeng Chong <jiapeng.chong-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
> ---
>  tools/testing/selftests/cgroup/cgroup_util.c | 2 +-
>  tools/testing/selftests/cgroup/cgroup_util.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
> index 4c52cc6f2f9c..661e06b94a43 100644
> --- a/tools/testing/selftests/cgroup/cgroup_util.c
> +++ b/tools/testing/selftests/cgroup/cgroup_util.c
> @@ -552,7 +552,7 @@ int proc_mount_contains(const char *option)
>  	return strstr(buf, option) != NULL;
>  }
>  
> -ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size)
> +ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, ssize_t size)

Converting input size parameter to ssize_t doesn't make sense. I don't see
where it's doing size < 0 either but that's probably where it should be
fixed.

-- 
tejun