rust_binder: freeze_notif_done should resend if wrong state

Consider the following scenario:
1. A freeze notification is delivered to thread 1.
2. The process becomes frozen or unfrozen.
3. The message for step 2 is delivered to thread 2 and ignored because
   there is already a pending notification from step 1.
4. Thread 1 acknowledges the notification from step 1.
In this case, step 4 should ensure that the message ignored in step 3 is
resent as it can now be delivered.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/android/binder/freeze.rs b/drivers/android/binder/freeze.rs
index e68c3c8bc55a..74bebb8d4d9b 100644
--- a/drivers/android/binder/freeze.rs
+++ b/drivers/android/binder/freeze.rs
@@ -245,8 +245,9 @@ impl Process {
                 );
                 return Err(EINVAL);
             }
-            if freeze.is_clearing {
-                // Immediately send another FreezeMessage for BR_CLEAR_FREEZE_NOTIFICATION_DONE.
+            let is_frozen = freeze.node.owner.inner.lock().is_frozen;
+            if freeze.is_clearing || freeze.last_is_frozen != Some(is_frozen) {
+                // Immediately send another FreezeMessage.
                 clear_msg = Some(FreezeMessage::init(alloc, cookie));
             }
             freeze.is_pending = false;