From 838234ed7e9cf87b740556c5e15e3e236b723fa4 Mon Sep 17 00:00:00 2001
From: hubin <hubin73@huawei.com>
Date: Thu, 18 May 2023 16:14:41 +0800
Subject: [PATCH 46/85] ras-events: quit loop in read_ras_event when kbuf data
 is broken

when kbuf data is broken, kbuffer_next_event() may move kbuf->index back to
the current kbuf->index position, causing dead loop.

In this situation, rasdaemon will repeatedly parse an invalid event, and
print warning like "ug! negative record size -8!", pushing cpu utilization
rate to 100%.

when kbuf data is broken, discard current page and continue reading next page
kbuf.

Signed-off-by: hubin <hubin73@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
---
 ras-events.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/ras-events.c b/ras-events.c
index e1326f3..2cc54b3 100644
--- a/ras-events.c
+++ b/ras-events.c
@@ -546,6 +546,11 @@ static int read_ras_event_all_cpus(struct pthread_data *pdata,
 				kbuffer_load_subbuffer(kbuf, page);
 
 				while ((data = kbuffer_read_event(kbuf, &time_stamp))) {
+					if (kbuffer_curr_size(kbuf) < 0) {
+						log(TERM, LOG_ERR, "invalid kbuf data, discard\n");
+						break;
+					}
+
 					parse_ras_data(&pdata[i],
 						       kbuf, data, time_stamp);
 
-- 
2.33.1