fs: ubootvarfs: fix double-free unlinking U-Boot variables

We free the struct ubootvarfs_inode::var as part of destroy_inode. In
case we have unlinked the U-Boot variable beforehand, we will end up
double-freeing. Set the member to NULL, so it's skipped in
destory_inode. We keep the free in destroy_inode, because that's still
needed for all the other inodes that aren't unlinked.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20220819105521.3848169-1-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/ubootvarfs.c b/fs/ubootvarfs.c
index 475e4b7a79..147fee1ea6 100644
--- a/fs/ubootvarfs.c
+++ b/fs/ubootvarfs.c
@@ -259,6 +259,7 @@ static int ubootvarfs_unlink(struct inode *dir, struct dentry *dentry)
 
 		list_del(&var->list);
 		free(var);
+		node->var = NULL;
 	}
 
 	return simple_unlink(dir, dentry);