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

From: Tejun Heo <tj@kernel.org>
To: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Cc: lizefan.x@bytedance.com, hannes@cmpxchg.org, shuah@kernel.org,
	cgroups@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Abaci Robot <abaci@linux.alibaba.com>
Subject: Re: [PATCH] selftests: cgroup: Fix unsigned expression compared with zero
Date: Wed, 27 Apr 2022 06:18:42 -1000	[thread overview]
Message-ID: <Ymls4pydYPMBtyCm@slm.duckdns.org> (raw)
In-Reply-To: <20220427061756.56893-1-jiapeng.chong@linux.alibaba.com>

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@linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> ---
>  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