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References: <20221105110611.28920-1-yuehaibing@huawei.com>
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From:   Yosry Ahmed <yosryahmed@google.com>
Date:   Sat, 5 Nov 2022 15:29:54 -0700
Message-ID: <CAJD7tkb06mjZ3bvoiR4U47+XknM4nTHY06RYZ8SULOxJ4mAOwQ@mail.gmail.com>
Subject: Re: [PATCH] selftests: cgroup: Fix unsigned comparison with less than zero
To:     YueHaibing <yuehaibing@huawei.com>
Cc:     tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org,
        shuah@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com,
        rientjes@google.com, akpm@linux-foundation.org,
        cgroups@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Sat, Nov 5, 2022 at 4:06 AM YueHaibing <yuehaibing@huawei.com> wrote:
>
> 'size' is unsigned, it never less than zero.
>
> Fixes: 6c26df84e1f2 ("selftests: cgroup: return -errno from cg_read()/cg_write() on failure")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>

Thanks for fixing this!
FWIW,

Reviewed-by: Yosry Ahmed <yosryahmed@google.com>


> ---
>  tools/testing/selftests/cgroup/cgroup_util.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
> index 4c52cc6f2f9c..e8bbbdb77e0d 100644
> --- a/tools/testing/selftests/cgroup/cgroup_util.c
> +++ b/tools/testing/selftests/cgroup/cgroup_util.c
> @@ -555,6 +555,7 @@ int proc_mount_contains(const char *option)
>  ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size)
>  {
>         char path[PATH_MAX];
> +       ssize_t ret;
>
>         if (!pid)
>                 snprintf(path, sizeof(path), "/proc/%s/%s",
> @@ -562,8 +563,8 @@ ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t
>         else
>                 snprintf(path, sizeof(path), "/proc/%d/%s", pid, item);
>
> -       size = read_text(path, buf, size);
> -       return size < 0 ? -1 : size;
> +       ret = read_text(path, buf, size);
> +       return ret < 0 ? -1 : ret;
>  }
>
>  int proc_read_strstr(int pid, bool thread, const char *item, const char *needle)
> --
> 2.17.1
>