[for-linus][PATCH 5/7] eventfs: Initialize ei->children and ei->list in init_ei()

[Steven Rostedt]

From: Deepanshu Kartikey <kartikey406@xxxxxxxxx>

eventfs_create_dir() allocates the eventfs_inode and initializes it with
init_ei(). But this does not initialize the eventfs_inode list_heads. If
the eventfs_create_dir() fails due to memory pressure, it will call
free_ei() before it initialized the lists, and that checks to make sure
the eventfs_inode has no children. But because the list wasn't
initialized, it will give a false warning.

Fix it by moving the list initialization into init_ei().

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5790b1fb3d67 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: syzbot+3ef80b4ed02226d04a06@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=3ef80b4ed02226d04a06
Link: https://patch.msgid.link/20260824144653.54044-1-kartikey406@xxxxxxxxx
Signed-off-by: Deepanshu Kartikey <kartikey406@xxxxxxxxx>
[ Rewrote change log ]
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 fs/tracefs/event_inode.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 604ba3e841d2..6e3513b13cfa 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -438,6 +438,8 @@ static inline struct eventfs_inode *init_ei(struct eventfs_inode *ei, const char
 	if (!ei->name)
 		return NULL;
 	kref_init(&ei->kref);
+	INIT_LIST_HEAD(&ei->children);
+	INIT_LIST_HEAD(&ei->list);
 	return ei;
 }
 
@@ -729,8 +731,6 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
 	ei->entries = entries;
 	ei->nr_entries = size;
 	ei->data = data;
-	INIT_LIST_HEAD(&ei->children);
-	INIT_LIST_HEAD(&ei->list);
 
 	scoped_guard(mutex, &eventfs_mutex) {
 		if (!parent->is_freed)
@@ -802,9 +802,6 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
 	ei->attr.uid = uid;
 	ei->attr.gid = gid;
 
-	INIT_LIST_HEAD(&ei->children);
-	INIT_LIST_HEAD(&ei->list);
-
 	ti = get_tracefs(inode);
 	ti->flags |= TRACEFS_EVENT_INODE;
 	ti->private = ei;
-- 
2.53.0