From 24daf290f93e3af5804872997a7a8c59adcfb7ce Mon Sep 17 00:00:00 2001
From: Mark Yen <mark.yen@suse.com>
Date: Wed, 4 Oct 2023 13:15:07 -0700
Subject: [PATCH] Rename cgroupNamespaceSupported, add details

This responds to review feedback from
https://github.com/moby/buildkit/pull/4308#pullrequestreview-1658246195

Signed-off-by: Mark Yen <mark.yen@suse.com>
---
 executor/oci/spec.go         | 2 +-
 executor/oci/spec_freebsd.go | 2 +-
 executor/oci/spec_linux.go   | 5 ++++-
 executor/oci/spec_windows.go | 2 +-
 4 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/executor/oci/spec.go b/executor/oci/spec.go
index 96aff5ffac55..849a70b90b5c 100644
--- a/executor/oci/spec.go
+++ b/executor/oci/spec.go
@@ -138,7 +138,7 @@ func GenerateSpec(ctx context.Context, meta executor.Meta, mounts []executor.Mou
 		return nil, nil, err
 	}
 
-	if cgroupNamespaceSupported() {
+	if cgroupV2NamespaceSupported() {
 		s.Linux.Namespaces = append(s.Linux.Namespaces, specs.LinuxNamespace{
 			Type: specs.CgroupNamespace,
 		})
diff --git a/executor/oci/spec_freebsd.go b/executor/oci/spec_freebsd.go
index 2707c6b4d887..abb18799de77 100644
--- a/executor/oci/spec_freebsd.go
+++ b/executor/oci/spec_freebsd.go
@@ -56,6 +56,6 @@ func getTracingSocket() string {
 	return ""
 }
 
-func cgroupNamespaceSupported() bool {
+func cgroupV2NamespaceSupported() bool {
 	return false
 }
diff --git a/executor/oci/spec_linux.go b/executor/oci/spec_linux.go
index 50121f79064b..5cf8e6c7ee68 100644
--- a/executor/oci/spec_linux.go
+++ b/executor/oci/spec_linux.go
@@ -148,7 +148,10 @@ func getTracingSocket() string {
 	return fmt.Sprintf("unix://%s", tracingSocketPath)
 }
 
-func cgroupNamespaceSupported() bool {
+func cgroupV2NamespaceSupported() bool {
+	// Check if cgroups v2 namespaces are supported.  Trying to do cgroup
+	// namespaces with cgroups v1 results in EINVAL when we encounter a
+	// non-standard hierarchy.
 	cgroupNSOnce.Do(func() {
 		if _, err := os.Stat("/proc/self/ns/cgroup"); os.IsNotExist(err) {
 			return
diff --git a/executor/oci/spec_windows.go b/executor/oci/spec_windows.go
index 0201bcd7689d..63266bb640fe 100644
--- a/executor/oci/spec_windows.go
+++ b/executor/oci/spec_windows.go
@@ -97,6 +97,6 @@ func getTracingSocket() string {
 	return fmt.Sprintf("npipe://%s", filepath.ToSlash(tracingSocketPath))
 }
 
-func cgroupNamespaceSupported() bool {
+func cgroupV2NamespaceSupported() bool {
 	return false
 }