Unverified Commit 2b60d56a authored by Christian Brauner's avatar Christian Brauner
Browse files

ns: add asserts for initial namespace reference counts 

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

Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-13-e8a9264e0fb9@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 657aeb43

include/linux/ns_common.h

+17 −9
Original line number Diff line number Diff line
@@ -60,10 +60,17 @@ static __always_inline __must_check int __ns_ref_active_read(const struct ns_com 
	return atomic_read(&ns->__ns_ref_active);

}



static __always_inline __must_check int __ns_ref_read(const struct ns_common *ns)

{

	return refcount_read(&ns->__ns_ref);

}



static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns)

{

	if (is_ns_init_id(ns))

	if (is_ns_init_id(ns)) {

		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);

		return false;

	}

	if (refcount_dec_and_test(&ns->__ns_ref)) {

		VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));

		return true;
@@ -73,31 +80,32 @@ static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns) 


static __always_inline __must_check bool __ns_ref_get(struct ns_common *ns)

{

	if (is_ns_init_id(ns))

	if (is_ns_init_id(ns)) {

		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);

		return true;

	}

	if (refcount_inc_not_zero(&ns->__ns_ref))

		return true;

	VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));

	return false;

}



static __always_inline __must_check int __ns_ref_read(const struct ns_common *ns)

{

	return refcount_read(&ns->__ns_ref);

}



static __always_inline void __ns_ref_inc(struct ns_common *ns)

{

	if (is_ns_init_id(ns))

	if (is_ns_init_id(ns)) {

		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);

		return;

	}

	refcount_inc(&ns->__ns_ref);

}



static __always_inline __must_check bool __ns_ref_dec_and_lock(struct ns_common *ns,

							       spinlock_t *ns_lock)

{

	if (is_ns_init_id(ns))

	if (is_ns_init_id(ns)) {

		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);

		return false;

	}

	return refcount_dec_and_lock(&ns->__ns_ref, ns_lock);

}