On Oct 2, 2019, at 5:04 AM, Ivan Khoronzhuk ivan.khoronzhuk@linaro.org 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 ‘setup_cgroup_environment’: samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:52:34: warning: ‘/cgroup.controllers’ 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: ‘snprintf’ 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: ‘/cgroup.subtree_control’ 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: ‘snprintf’ 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@linaro.org
Acked-by: Song Liu songliubraving@fb.com