[PATCH v4 10/21] sched: add per-task KStackWatch context

Jinchao Wang
2025-09-12T10:12:46Z

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