kasan: simplify async check in end_report()

Currently, end_report() does not call trace_error_report_end() for bugs
detected in either async or asymm mode (when kasan_async_fault_possible()
returns true), as the address of the bad access might be unknown.

However, for asymm mode, the address is known for faults triggered by read
operations.

Instead of using kasan_async_fault_possible(), simply check that the addr
is not NULL when calling trace_error_report_end().

Link: https://lkml.kernel.org/r/1c8ce43f97300300e62c941181afa2eb738965c5.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index d60ee8b..2d892ec 100644 (file)
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -112,7 +112,7 @@ static void start_report(unsigned long *flags)
 
 static void end_report(unsigned long *flags, unsigned long addr)
 {
-       if (!kasan_async_fault_possible())
+       if (addr)
                trace_error_report_end(ERROR_DETECTOR_KASAN, addr);
        pr_err("==================================================================\n");
        add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);