[PATCH v11 3/5] kasan: Add report for async mode

[Vincenzo Frascino]

KASAN provides an asynchronous mode of execution.

Add reporting functionality for this mode.

Cc: Dmitry Vyukov <dvyukov at google.com>
Cc: Andrey Ryabinin <aryabinin at virtuozzo.com>
Cc: Alexander Potapenko <glider at google.com>
Cc: Andrey Konovalov <andreyknvl at google.com>
Reviewed-by: Andrey Konovalov <andreyknvl at google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino at arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
---
 include/linux/kasan.h |  6 ++++++
 mm/kasan/report.c     | 17 ++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 1011e4f30284..6d8f3227c264 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -367,6 +367,12 @@ static inline void *kasan_reset_tag(const void *addr)
 
 #endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS*/
 
+#ifdef CONFIG_KASAN_HW_TAGS
+
+void kasan_report_async(void);
+
+#endif /* CONFIG_KASAN_HW_TAGS */
+
 #ifdef CONFIG_KASAN_SW_TAGS
 void __init kasan_init_sw_tags(void);
 #else
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 87b271206163..f147633f1f2b 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -87,7 +87,8 @@ static void start_report(unsigned long *flags)
 
 static void end_report(unsigned long *flags, unsigned long addr)
 {
-	trace_error_report_end(ERROR_DETECTOR_KASAN, addr);
+	if (!kasan_flag_async)
+		trace_error_report_end(ERROR_DETECTOR_KASAN, addr);
 	pr_err("==================================================================\n");
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irqrestore(&report_lock, *flags);
@@ -360,6 +361,20 @@ void kasan_report_invalid_free(void *object, unsigned long ip)
 	end_report(&flags, (unsigned long)object);
 }
 
+#ifdef CONFIG_KASAN_HW_TAGS
+void kasan_report_async(void)
+{
+	unsigned long flags;
+
+	start_report(&flags);
+	pr_err("BUG: KASAN: invalid-access\n");
+	pr_err("Asynchronous mode enabled: no access details available\n");
+	pr_err("\n");
+	dump_stack();
+	end_report(&flags, 0);
+}
+#endif /* CONFIG_KASAN_HW_TAGS */
+
 static void __kasan_report(unsigned long addr, size_t size, bool is_write,
 				unsigned long ip)
 {
-- 
2.30.0