kernfs: Acquire kernfs_rwsem in kernfs_notify_workfn().

kernfs_notify_workfn() dereferences kernfs_node::name and passes it
later to fsnotify(). If the node is renamed then the previously observed
name pointer becomes invalid.

Acquire kernfs_root::kernfs_rwsem to block renames of the node.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20250213145023.2820193-2-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sebastian Andrzej Siewior
2025-02-13 15:50:18 +01:00
committed by Greg Kroah-Hartman
parent a64dcfb451
commit 400188ae36
+2
View File
@@ -911,6 +911,7 @@ repeat:
/* kick fsnotify */
down_read(&root->kernfs_supers_rwsem);
down_read(&root->kernfs_rwsem);
list_for_each_entry(info, &kernfs_root(kn)->supers, node) {
struct kernfs_node *parent;
struct inode *p_inode = NULL;
@@ -947,6 +948,7 @@ repeat:
iput(inode);
}
up_read(&root->kernfs_rwsem);
up_read(&root->kernfs_supers_rwsem);
kernfs_put(kn);
goto repeat;