From: Gustavo A. R. Silva <garsilva@embeddedor.com>
Date: Mon, 10 Jul 2017 22:47:23 +0000 (-0700)
Subject: mm/memory_hotplug.c: add NULL check to avoid potential NULL pointer dereference
X-Git-Tag: v4.13-rc1~62^2~110
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=dbac61a3f2afac562efa51b0a196ed71b6b8d109;p=linux.git

mm/memory_hotplug.c: add NULL check to avoid potential NULL pointer dereference

The NULL check at line 1226: if (!pgdat), implies that pointer pgdat
might be NULL.

rollback_node_hotadd() dereferences this pointer.  Add NULL check to
avoid a potential NULL pointer dereference.

Addresses-Coverity-ID: 1369133
Link: http://lkml.kernel.org/r/20170530212436.GA6195@embeddedgus
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index f79aac7a12b5..7b1311ac5f7b 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1268,7 +1268,7 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
 
 error:
 	/* rollback pgdat allocation and others */
-	if (new_pgdat)
+	if (new_pgdat && pgdat)
 		rollback_node_hotadd(nid, pgdat);
 	memblock_remove(start, size);