mm/balloon_compaction: assert that the balloon_pages_lock is held

Let's add some sanity checks for holding the balloon_pages_lock when we're
effectively inflating/deflating a page.

Link: https://lkml.kernel.org/r/20260119230133.3551867-17-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 30fa7ee8e1f3a8c9ab8574d3e422d4e7596498b4..f77b305b04592c40f320c491c64c44239086a3e3 100644 (file)
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -28,6 +28,7 @@ static DEFINE_SPINLOCK(balloon_pages_lock);
 static void balloon_page_insert(struct balloon_dev_info *balloon,
                                       struct page *page)
 {
+       lockdep_assert_held(&balloon_pages_lock);
        __SetPageOffline(page);
        if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) {
                SetPageMovableOps(page);
@@ -45,6 +46,7 @@ static void balloon_page_insert(struct balloon_dev_info *balloon,
  */
 static void balloon_page_finalize(struct page *page)
 {
+       lockdep_assert_held(&balloon_pages_lock);
        if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
                set_page_private(page, 0);
        /* PageOffline is sticky until the page is freed to the buddy. */