This patch adds new helper functions to the kstackwatch module to aid in
debugging and testing.
- `ksw_watch_show()`: Displays information about the currently active hardware
breakpoint, such as its address and length. This is useful for verifying
that a breakpoint has been correctly installed.
- `ksw_watch_fire()`: Manually triggers the active hardware breakpoint. This
function is for testing the breakpoint handler to ensure it correctly
identifies and reports the stack corruption.
Signed-off-by: Jinchao Wang <wangjinchao...@gmail.com>
---
mm/kstackwatch/kstackwatch.h | 4 ++++
mm/kstackwatch/watch.c | 20 ++++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h
index c24a651977c0..27c71a9391ac 100644
--- a/mm/kstackwatch/kstackwatch.h
+++ b/mm/kstackwatch/kstackwatch.h
@@ -2,6 +2,8 @@
#ifndef _KSTACKWATCH_H
#define _KSTACKWATCH_H
+#include <linux/kprobes.h>
+#include <linux/perf_event.h>
#include <linux/types.h>
#define MAX_FUNC_NAME_LEN 64
@@ -48,5 +50,7 @@ int ksw_watch_init(struct ksw_config *config);
void ksw_watch_exit(void);
int ksw_watch_on(u64 watch_addr, u64 watch_len);
void ksw_watch_off(void);
+void ksw_watch_show(void);
+void ksw_watch_fire(void);
#endif /* _KSTACKWATCH_H */
diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c
index 1b4cf5d42db9..28ea24e4ae3a 100644
--- a/mm/kstackwatch/watch.c
+++ b/mm/kstackwatch/watch.c
@@ -218,3 +218,23 @@ void ksw_watch_off(void)
ksw_watch_on((unsigned long)&marker, sizeof(marker));
pr_info("KSW: All HWBPs disarmed\n");
}
+
+/* Debug functions */
+void ksw_watch_show(void)
+{
+ struct perf_event *bp;
+
+ bp = *this_cpu_ptr(watch_events);
+ pr_info("KSW: HWBP info test - bp_addr: 0x%px len:%llu\n",
+ (void *)bp->attr.bp_addr, bp->attr.bp_len);
+}
+
+void ksw_watch_fire(void)
+{
+ struct perf_event *bp;
+ char *ptr;
+
+ bp = *this_cpu_ptr(watch_events);
+ ptr = (char *)READ_ONCE(bp->attr.bp_addr);
+ *ptr = 0x42; // This should trigger immediately
+}
--
2.43.0
