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 <[email protected]>
---
tools/testing/selftests/bpf/cgroup_helpers.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c
b/tools/testing/selftests/bpf/cgroup_helpers.c
index 4d74f3c4619b..0fb910df5387 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.c
+++ b/tools/testing/selftests/bpf/cgroup_helpers.c
@@ -98,7 +98,7 @@ static int enable_all_controllers(char *cgroup_path)
*/
int setup_cgroup_environment(void)
{
- char cgroup_workdir[PATH_MAX + 1];
+ char cgroup_workdir[PATH_MAX - 24];
format_cgroup_path(cgroup_workdir, "");
--
2.17.1
