Introduce struct kstackwatch_ctx to enable lockless per-task state
tracking.  This is required because KStackWatch operates in NMI context
(via kprobe handler) where traditional locking is unsafe.

Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
---
 include/linux/kstackwatch_types.h | 13 +++++++++++++
 include/linux/sched.h             |  5 +++++
 2 files changed, 18 insertions(+)
 create mode 100644 include/linux/kstackwatch_types.h

diff --git a/include/linux/kstackwatch_types.h b/include/linux/kstackwatch_types.h
new file mode 100644
index 000000000000..93855fcc7981
--- /dev/null
+++ b/include/linux/kstackwatch_types.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KSTACK_WATCH_TYPES_H
+#define _LINUX_KSTACK_WATCH_TYPES_H
+#include <linux/types.h>
+
+struct kstackwatch_ctx {
+	ulong watch_addr;
+	u16 watch_len;
+	u16 depth;
+	bool watch_on;
+};
+
+#endif /* _LINUX_KSTACK_WATCH_TYPES_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index f8188b833350..1b324b458309 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -22,6 +22,7 @@
 #include <linux/sem_types.h>
 #include <linux/shm.h>
 #include <linux/kmsan_types.h>
+#include <linux/kstackwatch_types.h>
 #include <linux/mutex_types.h>
 #include <linux/plist_types.h>
 #include <linux/hrtimer_types.h>
@@ -1481,6 +1482,10 @@ struct task_struct {
 	struct kmsan_ctx		kmsan_ctx;
 #endif
 
+#if IS_ENABLED(CONFIG_KSTACK_WATCH)
+	struct kstackwatch_ctx		kstackwatch_ctx;
+#endif
+
 #if IS_ENABLED(CONFIG_KUNIT)
 	struct kunit			*kunit_test;
 #endif
-- 
2.43.0