[PATCH 2/3] kfence: use error_report_end tracepoint

[Alexander Potapenko <glider@xxxxxxxxxx>]

Make it possible to trace KFENCE error reporting. A good usecase is
watching for trace events from the userspace to detect and process
memory corruption reports from the kernel.

Suggested-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>

---
v3:
 - dropped error_report_start

v2:
 - change error_report_start and error_report_end prototypes
   to accept enum error_detector instead of char*
   (as suggested by Steven Rostedt)
---
 mm/kfence/report.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/kfence/report.c b/mm/kfence/report.c
index 901bd7ee83d8..f9fc93b2fe2e 100644
--- a/mm/kfence/report.c
+++ b/mm/kfence/report.c
@@ -14,6 +14,7 @@
 #include <linux/seq_file.h>
 #include <linux/stacktrace.h>
 #include <linux/string.h>
+#include <trace/events/error_report.h>
 
 #include <asm/kfence.h>
 
@@ -246,6 +247,7 @@ void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r
 		show_regs(regs);
 	else
 		dump_stack_print_info(KERN_ERR);
+	trace_error_report_end(ERROR_DETECTOR_KFENCE, address);
 	pr_err("==================================================================\n");
 
 	lockdep_on();
-- 
2.30.0.296.g2bfb1c46d8-goog