linux-kernel - [PATCH] mm: add NULL check to avoid potential NULL pointer dereference

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Date:   Tue, 30 May 2017 16:24:36 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     linux-mm@...ck.org
Cc:     linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: [PATCH] mm: add NULL check to avoid potential NULL pointer
 dereference

NULL check at line 1226: if (!pgdat), implies that pointer pgdat
might be NULL.
Function rollback_node_hotadd() dereference this pointer.
Add NULL check to avoid a potential NULL pointer dereference.

Addresses-Coverity-ID: 1369133
Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
---
 mm/memory_hotplug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 599c675..ea3bc3e 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1273,7 +1273,7 @@ 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);
 
-- 
2.5.0