On Mon, Feb 20, 2017 at 04:47:05PM -0800, James Bottomley wrote: [..] > +static struct dentry *shiftfs_lookup(struct inode *dir, struct dentry *dentry, > + unsigned int flags) > +{ > + struct dentry *real = dir->i_private, *new; > + struct inode *reali = real->d_inode, *newi; newi needs to be initialized to NULL. Otherwise if a file does not exist, we try to call d_splice_alias() with uninitialized value of newi. This crashes for the new file creation case. Vivek