kasan: Add report for async mode

KASAN provides an asynchronous mode of execution.

Add reporting functionality for this mode.

Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/20210315132019.33202-5-vincenzo.frascino@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index b91732bd05d781975a1da533170ae71cf2a31d08..e7c20c79b342610e13e07fc26ad51da6b55b7358 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -376,6 +376,12 @@ 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/kasan.h b/mm/kasan/kasan.h
index a3d0d165d97d1f4376067247cf1ba81f9aeffe1a..02e9656b857fbe70b139acdb794edf82ddc2b32b 100644 (file)
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -7,17 +7,33 @@
 #include <linux/stackdepot.h>
 
 #ifdef CONFIG_KASAN_HW_TAGS
+
 #include <linux/static_key.h>
+
 DECLARE_STATIC_KEY_FALSE(kasan_flag_stacktrace);
+extern bool kasan_flag_async __ro_after_init;
+
 static inline bool kasan_stack_collection_enabled(void)
 {
        return static_branch_unlikely(&kasan_flag_stacktrace);
 }
+
+static inline bool kasan_async_mode_enabled(void)
+{
+       return kasan_flag_async;
+}
 #else
+
 static inline bool kasan_stack_collection_enabled(void)
 {
        return true;
 }
+
+static inline bool kasan_async_mode_enabled(void)
+{
+       return false;
+}
+
 #endif
 
 extern bool kasan_flag_panic __ro_after_init;

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 87b271206163b8682f818276158812a1c01fe3eb..8b0843a2cdd711515a8ff32a9f5e2807faa472b2 100644 (file)
--- 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_async_mode_enabled())
+               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)
 {