Re: [PATCH bpf-next 2/2] selftests/bpf: correct path to include msg + path

[Song Liu]

> On Oct 2, 2019, at 5:04 AM, Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> wrote:
> 
> The "path" buf is supposed to contain path + printf msg up to 24 bytes.
> It will be cut anyway, but compiler generates truncation warns like:
> 
> "
> samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c: In
> function âsetup_cgroup_environmentâ:
> samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:52:34:
> warning: â/cgroup.controllersâ directive output may be truncated
> writing 19 bytes into a region of size between 1 and 4097
> [-Wformat-truncation=]
> snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path);
> 				  ^~~~~~~~~~~~~~~~~~~
> samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:52:2:
> note: âsnprintfâ output between 20 and 4116 bytes into a destination
> of size 4097
> snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:72:34:
> warning: â/cgroup.subtree_controlâ directive output may be truncated
> writing 23 bytes into a region of size between 1 and 4097
> [-Wformat-truncation=]
> snprintf(path, sizeof(path), "%s/cgroup.subtree_control",
> 				  ^~~~~~~~~~~~~~~~~~~~~~~
> cgroup_path);
> samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:72:2:
> note: âsnprintfâ output between 24 and 4120 bytes into a destination
> of size 4097
> snprintf(path, sizeof(path), "%s/cgroup.subtree_control",
> cgroup_path);
> "
> 
> In order to avoid warns, lets decrease buf size for cgroup workdir on
> 24 bytes with assumption to include also "/cgroup.subtree_control" to
> the address. The cut will never happen anyway.
> 
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>


Acked-by: Song Liu <songliubraving@xxxxxx>