On Fri, Jan 29, 2021 at 6:44 PM Vincenzo Frascino
[off-list ref] wrote:

On 1/29/21 5:40 PM, Andrey Konovalov wrote:

quoted

On Tue, Jan 26, 2021 at 2:46 PM Vincenzo Frascino
[off-list ref] wrote:

quoted

KASAN provides an asynchronous mode of execution.

Add reporting functionality for this mode.

Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <redacted>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <redacted>
Reviewed-by: Andrey Konovalov <redacted>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
 include/linux/kasan.h |  6 ++++++
 mm/kasan/report.c     | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index bb862d1f0e15..b6c502dad54d 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h

@@ -360,6 +360,12 @@ 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..69bad9c01aed 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c

@@ -360,6 +360,19 @@ 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");

Could you also add an empty line here before the stack trace while at it?

quoted

quoted

+       dump_stack();
+       end_report(&flags);

This conflicts with "kasan: use error_report_end tracepoint" that's in mm.

I suggest to call end_report(&flags, 0) here and check addr !=0 in
end_report() before calling trace_error_report_end().

I just noticed and about to post a rebased version with end_report(&flags, 0).

quoted

quoted

+}
+#endif /* CONFIG_KASAN_HW_TAGS */
+
 static void __kasan_report(unsigned long addr, size_t size, bool is_write,
                                unsigned long ip)
 {
--
2.30.0

--
Regards,
Vincenzo

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