staging: lustre: fix error deref in ll_splice_alias().

d_splice_alias() can return an ERR_PTR().
If it does while debugging is enabled, the following
CDEBUG() will dereference that error and crash.

So add appropriate checking, and provide a separate
debug message for the error case.

Reported-and-tested-by: James Simmons <jsimmons@infradead.org>
Fixes: e9d4f0b9f5 ("staging: lustre: llite: use d_splice_alias for directories.")
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
NeilBrown 2018-05-07 10:54:48 +10:00 committed by Greg Kroah-Hartman
parent 9604c7ac20
commit 1d6e65bedf
1 changed files with 7 additions and 2 deletions

View File

@ -442,11 +442,16 @@ struct dentry *ll_splice_alias(struct inode *inode, struct dentry *de)
} else {
struct dentry *new = d_splice_alias(inode, de);
if (IS_ERR(new))
CDEBUG(D_DENTRY,
"splice inode %p as %pd gives error %lu\n",
inode, de, PTR_ERR(new));
if (new)
de = new;
}
CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n",
de, d_inode(de), d_count(de), de->d_flags);
if (!IS_ERR(de))
CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n",
de, d_inode(de), d_count(de), de->d_flags);
return de;
}