From: Vahram Martirosyan <vmartirosyan@gmail.com>
Date: Wed, 28 Nov 2012 17:44:16 +0000 (-0500)
Subject: ext4: fixed potential NULL dereference in ext4_calculate_overhead()
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=766f44d46a726cb59f52a75c5c87425a10c4bade;p=deliverable%2Flinux.git

ext4: fixed potential NULL dereference in ext4_calculate_overhead()

The memset operation before check can cause a BUG if the memory
allocation failed.  Since we are using get_zeroed_age, there is no
need to use memset anyway.

Found by the Spruce system in cooperation with the KEDR Framework.

Signed-off-by: Vahram Martirosyan <vmartirosyan@linuxtesting.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ad6cd8aeb946..66a4e20424cf 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3206,7 +3206,6 @@ int ext4_calculate_overhead(struct super_block *sb)
 	ext4_fsblk_t overhead = 0;
 	char *buf = (char *) get_zeroed_page(GFP_KERNEL);
 
-	memset(buf, 0, PAGE_SIZE);
 	if (!buf)
 		return -ENOMEM;