eventfs: Use list_add_tail_rcu() for SRCU-protected children list

Commit d2603279c7d6 ("eventfs: Use list_del_rcu() for SRCU protected
list variable") converted the removal side to pair with the
list_for_each_entry_srcu() walker in eventfs_iterate(). The insertion
in eventfs_create_dir() was left as a plain list_add_tail(), which on
weakly-ordered architectures can expose a new entry to the SRCU reader
before its list pointers and fields are observable.

Use list_add_tail_rcu() so the publication pairs with the existing
list_del_rcu() and list_for_each_entry_srcu().

Fixes: 43aa6f97c2d0 ("eventfs: Get rid of dentry pointers without refcounts")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260418152251.199343-1-devnexen@gmail.com
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 81df94038f2e24d9fc30c2bf6c3c12e377a4dde4..8dd554508828b8142bf39831d266b2c56bf27d2c 100644 (file)
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -706,7 +706,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
 
        scoped_guard(mutex, &eventfs_mutex) {
                if (!parent->is_freed)
-                       list_add_tail(&ei->list, &parent->children);
+                       list_add_tail_rcu(&ei->list, &parent->children);
        }
        /* Was the parent freed? */
        if (list_empty(&ei->list)) {