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 ad6cd8a..66a4e20 100644 (file)
--- 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;