rust_binder: Implement the BINDER_DEBUG_DEAD_TRANSACTION

logging mask to trace in-flight cancellations during teardown

This adds dynamic debug logs for:
- Releasing active transactions during thread stack unwinding.
- Discarded transaction error codes when a thread exits.
- Undelivered transaction acknowledgments (TRANSACTION_COMPLETE)
  upon thread exit.
- Undelivered process death and freeze notifications when processes
  exit or die.
- Undelivered transactions canceled due to target process death.

Change-Id: Iad322cb89497087dfc9e1d52850cf74afb55b6b5
Signed-off-by: Jahnavi MN <jahnavimn@google.com>

Author: jahnavi-MN496

drivers/android/binder/freeze.rs

@@ -140,7 +140,13 @@ impl DeliverToRead for FreezeMessage {
         }
     }
 
-    fn cancel(self: DArc<Self>) {}
+    fn cancel(self: DArc<Self>) {
+        binder_debug!(
+            DeadTransaction,
+            "undelivered freeze notification, {:016x}",
+            self.cookie.0
+        );
+    }
 
     fn should_sync_wakeup(&self) -> bool {
         false

drivers/android/binder/node.rs

@@ -1123,7 +1123,13 @@ impl DeliverToRead for NodeDeath {
         Ok(cmd != BR_DEAD_BINDER)
     }
 
-    fn cancel(self: DArc<Self>) {}
+    fn cancel(self: DArc<Self>) {
+        binder_debug!(
+            DeadTransaction,
+            "undelivered death notification, {:016x}",
+            self.cookie
+        );
+    }
 
     fn should_sync_wakeup(&self) -> bool {
         false

drivers/android/binder/rust_binder_main.rs

@@ -257,7 +257,14 @@ impl DeliverToRead for DeliverCode {
         Ok(true)
     }
 
-    fn cancel(self: DArc<Self>) {}
+    fn cancel(self: DArc<Self>) {
+        if !self.skip.load(Relaxed) {
+            binder_debug!(
+                DeadTransaction,
+                "undelivered TRANSACTION_COMPLETE"
+            );
+        }
+    }
 
     fn should_sync_wakeup(&self) -> bool {
         false

drivers/android/binder/thread.rs

@@ -1160,6 +1160,13 @@ impl Thread {
             let mut inner = thread.inner.lock();
             inner.pop_transaction_to_reply(thread.as_ref())
         } {
+            binder_debug!(
+                DeadTransaction,
+                "release process {} transaction {} in, still active",
+                self.process.task.pid(),
+                transaction.debug_id
+            );
+
             let reply = Err(BR_DEAD_REPLY);
             if !transaction
                 .from
@@ -1235,7 +1242,6 @@ impl Thread {
                     inner.push_reply_work(code)
                 }
             }
-            }
         };
 
         // Notify the thread now that we've released the inner lock.
@@ -1754,7 +1760,15 @@ impl DeliverToRead for ThreadError {
         Ok(true)
     }
 
-    fn cancel(self: DArc<Self>) {}
+    fn cancel(self: DArc<Self>) {
+        let code = self.error_code.load(Relaxed);
+        if code != BR_OK {
+            binder_debug!(
+                DeadTransaction,
+                "undelivered TRANSACTION_ERROR: {code}"
+            );
+        }
+    }
 
     fn should_sync_wakeup(&self) -> bool {
         false

drivers/android/binder/transaction.rs

@@ -534,6 +534,12 @@ impl DeliverToRead for Transaction {
         if self.target_node.is_some() && self.flags & TF_ONE_WAY == 0 {
             let reply = Err(BR_DEAD_REPLY);
             self.from.deliver_reply(reply, &self, None);
+        } else {
+            binder_debug!(
+                DeadTransaction,
+                "undelivered transaction {}, process died",
+                self.debug_id
+            );
         }
 
         self.drop_outstanding_txn();