Merge tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipgrafted

Pull futex fix from Ingo Molnar:

 - Also allocate a default private futex hash on vfork() as well, to
   avoid races with (private) futex waiters (Peter Zijlstra)

* tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Also allocate private hash on vfork()

1 files changed, 72 insertions, 0 deletions

diff --git a/drivers/dma-buf/sync_debug.h b/drivers/dma-buf/sync_debug.h
new file mode 100644
index 000000000..c49324505
--- /dev/null
+++ b/drivers/dma-buf/sync_debug.h
@@ -0,0 +1,72 @@
+/*
+ * Sync File validation framework and debug infomation
+ *
+ * Copyright (C) 2012 Google, Inc.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _LINUX_SYNC_H
+#define _LINUX_SYNC_H
+
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/dma-fence.h>
+
+#include <linux/sync_file.h>
+#include <uapi/linux/sync_file.h>
+
+/**
+ * struct sync_timeline - sync object
+ * @kref:		reference count on fence.
+ * @name:		name of the sync_timeline. Useful for debugging
+ * @lock:		lock protecting @pt_list and @value
+ * @pt_tree:		rbtree of active (unsignaled/errored) sync_pts
+ * @pt_list:		list of active (unsignaled/errored) sync_pts
+ * @sync_timeline_list:	membership in global sync_timeline_list
+ */
+struct sync_timeline {
+	struct kref		kref;
+	char			name[32];
+
+	/* protected by lock */
+	u64			context;
+	int			value;
+
+	struct rb_root		pt_tree;
+	struct list_head	pt_list;
+	spinlock_t		lock;
+
+	struct list_head	sync_timeline_list;
+};
+
+static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence)
+{
+	return container_of(fence->extern_lock, struct sync_timeline, lock);
+}
+
+/**
+ * struct sync_pt - sync_pt object
+ * @base: base fence object
+ * @link: link on the sync timeline's list
+ * @node: node in the sync timeline's tree
+ * @deadline: the earliest fence deadline hint
+ */
+struct sync_pt {
+	struct dma_fence base;
+	struct list_head link;
+	struct rb_node node;
+	ktime_t deadline;
+};
+
+extern const struct file_operations sw_sync_debugfs_fops;
+
+void sync_timeline_debug_add(struct sync_timeline *obj);
+void sync_timeline_debug_remove(struct sync_timeline *obj);
+
+#endif /* _LINUX_SYNC_H */