Re: [syzbot] [udf?] general protection fault in udf_read_folio

[Edward Adam Davis]

In erofs_bread(),
	folio = read_mapping_folio(buf->mapping, index, NULL);
file is NULL, it triger this issue.

#syz test

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 4726a4d014b6..fb8121edee8f 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -220,7 +220,7 @@ static void udf_adinicb_read_folio(struct folio *folio)
 
 static int udf_read_folio(struct file *file, struct folio *folio)
 {
-	struct udf_inode_info *iinfo = UDF_I(file_inode(file));
+	struct udf_inode_info *iinfo = UDF_I(folio->mapping->host);
 
 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 		udf_adinicb_read_folio(folio);