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authorRitesh Harjani <riteshh@linux.ibm.com>2020-05-10 11:54:49 +0530
committerTheodore Ts'o <tytso@mit.edu>2020-06-03 23:16:52 -0400
commiteb2b8ebb867fa895d5c4768310998bc940f6506c (patch)
tree79a7a2e2c068c0ea6d0097b4148c0bc0c0b173e9 /fs/ext4
parenta345021553f7e6343b05b1ad1c25ed931140b47c (diff)
ext4: mballoc: fix possible NULL ptr & remove BUG_ONs from DOUBLE_CHECK
Make sure to check for e4b->bd_info->bb_bitmap == NULL, in mb_cmp_bitmaps() and return if NULL, to avoid possible NULL ptr dereference. Similar to how we do this in other ifdef DOUBLE_CHECK functions. Also remove the BUG_ON() logic if kmalloc() or ext4_read_block_bitmap() fails. We should simply mark grp->bb_bitmap as NULL if above happens. In fact ext4_read_block_bitmap() may even return an error in case of resize ioctl. Hence remove this BUG_ON logic (fstests ext4/032 may trigger this). Link: https://lore.kernel.org/r/9a54f8a696ff17c057cd571be3d15ac3ec1407f1.1589086800.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/mballoc.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 3555e72f149c..c713d06e70b7 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -493,6 +493,8 @@ static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
+ if (unlikely(e4b->bd_info->bb_bitmap == NULL))
+ return;
if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
unsigned char *b1, *b2;
int i;
@@ -517,10 +519,15 @@ static void mb_group_bb_bitmap_alloc(struct super_block *sb,
struct buffer_head *bh;
grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS);
- BUG_ON(grp->bb_bitmap == NULL);
+ if (!grp->bb_bitmap)
+ return;
bh = ext4_read_block_bitmap(sb, group);
- BUG_ON(IS_ERR_OR_NULL(bh));
+ if (IS_ERR_OR_NULL(bh)) {
+ kfree(grp->bb_bitmap);
+ grp->bb_bitmap = NULL;
+ return;
+ }
memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize);
put_bh(bh);