From: Steven Rostedt (Google) <rostedt@goodmis.org>
Date: Sun, 12 Nov 2023 17:18:17 +0000 (-0500)
Subject: eventfs: Check for NULL ef in eventfs_set_attr()
X-Git-Tag: v6.6.17~3049
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d8f492a059728bbd397defbc9b8d2f4159d869b5;p=platform%2Fkernel%2Flinux-rpi.git

eventfs: Check for NULL ef in eventfs_set_attr()

The top level events directory dentry does not have a d_fsdata set to a
eventfs_file pointer. This dentry is still passed to eventfs_set_attr().
It can not assume that the d_fsdata is set. Check for that.

Link: https://lore.kernel.org/all/20231112104158.6638-1-milian.wolff@kdab.com/

Fixes: 9aaee3eebc91 ("eventfs: Save ownership and mode")
Reported-by: Milian Wolff <milian.wolff@kdab.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 5fcfb63..efbdc47 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -113,14 +113,14 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
 
 	mutex_lock(&eventfs_mutex);
 	ef = dentry->d_fsdata;
-	if (ef->is_freed) {
+	if (ef && ef->is_freed) {
 		/* Do not allow changes if the event is about to be removed. */
 		mutex_unlock(&eventfs_mutex);
 		return -ENODEV;
 	}
 
 	ret = simple_setattr(idmap, dentry, iattr);
-	if (!ret)
+	if (!ret && ef)
 		update_attr(ef, iattr);
 	mutex_unlock(&eventfs_mutex);
 	return ret;