xenbus: don't BUG() on user mode induced condition
Inability to locate a user mode specified transaction ID should not
lead to a kernel crash. For other than XS_TRANSACTION_START also
don't issue anything to xenbus if the specified ID doesn't match that
of any active transaction.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index cacf30d..7487971 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -316,11 +316,18 @@
rc = -ENOMEM;
goto out;
}
+ } else {
+ list_for_each_entry(trans, &u->transactions, list)
+ if (trans->handle.id == u->u.msg.tx_id)
+ break;
+ if (&trans->list == &u->transactions)
+ return -ESRCH;
}
reply = xenbus_dev_request_and_reply(&u->u.msg);
if (IS_ERR(reply)) {
- kfree(trans);
+ if (msg_type == XS_TRANSACTION_START)
+ kfree(trans);
rc = PTR_ERR(reply);
goto out;
}
@@ -333,12 +340,7 @@
list_add(&trans->list, &u->transactions);
}
} else if (u->u.msg.type == XS_TRANSACTION_END) {
- list_for_each_entry(trans, &u->transactions, list)
- if (trans->handle.id == u->u.msg.tx_id)
- break;
- BUG_ON(&trans->list == &u->transactions);
list_del(&trans->list);
-
kfree(trans);
}