[PATCH 14/17] ns: add asserts for initial namespace active reference counts

Christian Brauner
2025-11-10T15:09:54Z

They always remain fixed at one. Notice when that assumptions is broken.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
include/linux/ns_common.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index dfb6b798ba82..43f709ab846a 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h
@@ -69,6 +69,7 @@ static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns)
{
if (is_ns_init_id(ns)) {
VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+ VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
return false;
}
if (refcount_dec_and_test(&ns->__ns_ref)) {
@@ -82,6 +83,7 @@ static __always_inline __must_check bool __ns_ref_get(struct ns_common *ns)
{
if (is_ns_init_id(ns)) {
VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+ VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
return true;
}
if (refcount_inc_not_zero(&ns->__ns_ref))
@@ -94,6 +96,7 @@ static __always_inline void __ns_ref_inc(struct ns_common *ns)
{
if (is_ns_init_id(ns)) {
VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+ VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
return;
}
refcount_inc(&ns->__ns_ref);
@@ -104,6 +107,7 @@ static __always_inline __must_check bool __ns_ref_dec_and_lock(struct ns_common
{
if (is_ns_init_id(ns)) {
VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+ VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
return false;
}
return refcount_dec_and_lock(&ns->__ns_ref, ns_lock);

--
2.47.3