Forwarded: Testing for v3 scsi: target: fix recursive locking in __configfs_open_file()

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Subject: Testing for v3 scsi: target: fix recursive locking in __configfs_open_file()
Author: activprithvi@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 3a8660878839faadb4f1a6dd72c3179c1df56787 

---
 drivers/target/target_core_configfs.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index b19acd662726..f29052e6a87d 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -108,8 +108,8 @@ static ssize_t target_core_item_dbroot_store(struct config_item *item,
 					const char *page, size_t count)
 {
 	ssize_t read_bytes;
-	struct file *fp;
 	ssize_t r = -EINVAL;
+	struct path path = {};
 
 	mutex_lock(&target_devices_lock);
 	if (target_devices) {
@@ -131,17 +131,18 @@ static ssize_t target_core_item_dbroot_store(struct config_item *item,
 		db_root_stage[read_bytes - 1] = '\0';
 
 	/* validate new db root before accepting it */
-	fp = filp_open(db_root_stage, O_RDONLY, 0);
-	if (IS_ERR(fp)) {
+	r = kern_path(db_root_stage, LOOKUP_FOLLOW, &path);
+	if (r) {
 		pr_err("db_root: cannot open: %s\n", db_root_stage);
 		goto unlock;
 	}
-	if (!S_ISDIR(file_inode(fp)->i_mode)) {
-		filp_close(fp, NULL);
+	if (!d_is_dir(path.dentry)) {
+		path_put(&path);
 		pr_err("db_root: not a directory: %s\n", db_root_stage);
+		r = -ENOTDIR;
 		goto unlock;
 	}
-	filp_close(fp, NULL);
+	path_put(&path);
 
 	strscpy(db_root, db_root_stage);
 	pr_debug("Target_Core_ConfigFS: db_root set to %s\n", db_root);

base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
-- 
2.34.1