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[PATCH 4.9 18/78] hfs: prevent crash on exit from failed search




4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Ernesto A. Fern�ez" <ernesto.mnd.fernandez@xxxxxxxxx>

[ Upstream commit dc2572791d3a41bab94400af2b6bca9d71ccd303 ]

hfs_find_exit() expects fd->bnode to be NULL after a search has failed.
hfs_brec_insert() may instead set it to an error-valued pointer.  Fix
this to prevent a crash.

Link: http://lkml.kernel.org/r/53d9749a029c41b4016c495fc5838c9dba3afc52.1530294815.git.ernesto.mnd.fernandez@xxxxxxxxx
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@xxxxxxxxx>
Cc: Anatoly Trosinenko <anatoly.trosinenko@xxxxxxxxx>
Cc: Viacheslav Dubeyko <slava@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/hfs/brec.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -74,9 +74,10 @@ int hfs_brec_insert(struct hfs_find_data
 	if (!fd->bnode) {
 		if (!tree->root)
 			hfs_btree_inc_height(tree);
-		fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
-		if (IS_ERR(fd->bnode))
-			return PTR_ERR(fd->bnode);
+		node = hfs_bnode_find(tree, tree->leaf_head);
+		if (IS_ERR(node))
+			return PTR_ERR(node);
+		fd->bnode = node;
 		fd->record = -1;
 	}
 	new_node = NULL;