From: Namjae Jeon <namjae.jeon@samsung.com>
Date: Sat, 12 Jul 2014 20:11:42 +0000 (-0400)
Subject: ext4: fix potential null pointer dereference in ext4_free_inode
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=bf40c92635d63fcc574c52649f7cda13e0418ac1;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

ext4: fix potential null pointer dereference in ext4_free_inode

Fix potential null pointer dereferencing problem caused by e43bb4e612
("ext4: decrement free clusters/inodes counters when block group declared bad")

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
---

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 0840bf321cdb..5b87fc36aab8 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -338,7 +338,7 @@ out:
 			fatal = err;
 	} else {
 		ext4_error(sb, "bit already cleared for inode %lu", ino);
-		if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
+		if (gdp && !EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 			int count;
 			count = ext4_free_inodes_count(sb, gdp);
 			percpu_counter_sub(&sbi->s_freeinodes_counter,