From: Miklos Szeredi mszeredi@redhat.com
stable inclusion from linux-4.19.177 commit 1d775f15e900453c78eb43f5b9ff0bc10f229119
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commit cef4cbff06fbc3be54d6d79ee139edecc2ee8598 upstream.
There was a syzbot report with this warning but insufficient information...
Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/overlayfs/super.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index c5aa30aa902d..40fd013871a3 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -82,7 +82,7 @@ static void ovl_dentry_release(struct dentry *dentry) 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) @@ -101,9 +101,10 @@ static struct dentry *ovl_d_real(struct dentry *dentry, 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); @@ -111,8 +112,10 @@ static struct dentry *ovl_d_real(struct dentry *dentry, 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; }