From c3b739527258dae7ebe4b5d083a33ce527675082 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Tue, 9 Oct 2018 18:03:07 -0500
Subject: [PATCH] libmultipath: fix memory issue in path_latency prio

The path_latency prioriziter was assuming that prepare_directio_read()
always succeeds. However, it doesn't, and when it fails, the prioritizer
used buf without it pointing to alloced memory. Found by coverity.

Reviewed-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmultipath/prioritizers/path_latency.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libmultipath/prioritizers/path_latency.c b/libmultipath/prioritizers/path_latency.c
index 765265c0..eeee01e1 100644
--- a/libmultipath/prioritizers/path_latency.c
+++ b/libmultipath/prioritizers/path_latency.c
@@ -237,7 +237,8 @@ int getprio(struct path *pp, char *args, unsigned int timeout)
 	lg_maxavglatency = log(MAX_AVG_LATENCY) / lg_base;
 	lg_minavglatency = log(MIN_AVG_LATENCY) / lg_base;
 
-	prepare_directio_read(pp->fd, &blksize, &buf, &restore_flags);
+	if (prepare_directio_read(pp->fd, &blksize, &buf, &restore_flags) < 0)
+		return PRIO_UNDEF;
 
 	temp = io_num;
 	while (temp-- > 0) {
-- 
2.11.0