freevxfs: possible null pointer dereference fix

sb_read may return NULL, so let's explicitly check it.

Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/freevxfs/vxfs_bmap.c b/fs/freevxfs/vxfs_bmap.c
index 2d71128..f86fd3c 100644 (file)
--- a/fs/freevxfs/vxfs_bmap.c
+++ b/fs/freevxfs/vxfs_bmap.c
@@ -137,7 +137,7 @@ vxfs_bmap_indir(struct inode *ip, long indir, int size, long block)
 
                bp = sb_bread(ip->i_sb,
                                indir + (i / VXFS_TYPED_PER_BLOCK(ip->i_sb)));
-               if (!buffer_mapped(bp))
+               if (!bp || !buffer_mapped(bp))
                        return 0;
 
                typ = ((struct vxfs_typed *)bp->b_data) +

diff --git a/fs/freevxfs/vxfs_inode.c b/fs/freevxfs/vxfs_inode.c
index 098a915..d1f7c5b 100644 (file)
--- a/fs/freevxfs/vxfs_inode.c
+++ b/fs/freevxfs/vxfs_inode.c
@@ -99,7 +99,7 @@ vxfs_blkiget(struct super_block *sbp, u_long extent, ino_t ino)
        offset = ((ino % (sbp->s_blocksize / VXFS_ISIZE)) * VXFS_ISIZE);
        bp = sb_bread(sbp, block);
 
-       if (buffer_mapped(bp)) {
+       if (bp && buffer_mapped(bp)) {
                struct vxfs_inode_info  *vip;
                struct vxfs_dinode      *dip;