[PATCH 83/94] ext4: fix potential null pointer dereference in ext4_free_inode

[Sam Asadi]

From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Signed-off-by: Ashish Sangwan <a.sangwan@xxxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx>
Signed-off-by: sam-the-6 <asadi.samuel@xxxxxxxxx>
---
 fs/ext4/ialloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 0840bf3..5b87fc3 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,
-- 
1.7.10.4

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