From: Miklos Szeredi <mszeredi@xxxxxxxxxx> commit cef4cbff06fbc3be54d6d79ee139edecc2ee8598 upstream. There was a syzbot report with this warning but insufficient information... Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/overlayfs/super.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -79,7 +79,7 @@ static void ovl_dentry_release(struct de static struct dentry *ovl_d_real(struct dentry *dentry, const struct inode *inode) { - struct dentry *real; + struct dentry *real = NULL, *lower; /* It's an overlay file */ if (inode && d_inode(dentry) == inode) @@ -98,9 +98,10 @@ static struct dentry *ovl_d_real(struct if (real && !inode && ovl_has_upperdata(d_inode(dentry))) return real; - real = ovl_dentry_lowerdata(dentry); - if (!real) + lower = ovl_dentry_lowerdata(dentry); + if (!lower) goto bug; + real = lower; /* Handle recursion */ real = d_real(real, inode); @@ -108,8 +109,10 @@ static struct dentry *ovl_d_real(struct if (!inode || inode == d_inode(real)) return real; bug: - WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, - inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); + WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", + __func__, dentry, inode ? inode->i_sb->s_id : "NULL", + inode ? inode->i_ino : 0, real, + real && d_inode(real) ? d_inode(real)->i_ino : 0); return dentry; }