[PATCH v4 5/7] rust_binder: Implement BINDER_DEBUG_FAILED_TRANSACTION

[Jahnavi MN via B4 Relay <devnull+jahnavimn.google.com@kernel.org>]

From: Jahnavi MN <jahnavimn@google.com>

This adds dynamic debug logs for:
- Failed replies, target process deaths, and error code deliveries.
- Detailed transaction failure diagnostics (including sender/receiver
  PIDs, TIDs, transaction IDs, buffer sizes, and error codes).

Reviewed-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Jahnavi MN <jahnavimn@google.com>
---
 drivers/android/binder/thread.rs      | 21 ++++++++++++++++-----
 drivers/android/binder/transaction.rs |  8 ++++++++
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/android/binder/thread.rs b/drivers/android/binder/thread.rs
index 9f0178a13d6f..38b90c79c057 100644
--- a/drivers/android/binder/thread.rs
+++ b/drivers/android/binder/thread.rs
@@ -1275,11 +1275,22 @@ fn transaction(self: &Arc<Self>, cmd: u32, reader: &mut UserSliceReader) -> Resu
                     }
                 }
 
-                pr_warn!(
-                    "{}:{} transaction to {} failed: {err:?}",
-                    info.from_pid,
-                    info.from_tid,
-                    info.to_pid
+                binder_debug!(
+                    FailedTransaction,
+                    "transaction {} to {}:{} failed {:?}, code {} size {}-{}",
+                    if info.is_reply {
+                        "reply"
+                    } else if info.is_oneway() {
+                        "async"
+                    } else {
+                        "call"
+                    },
+                    info.to_pid,
+                    info.to_tid,
+                    err,
+                    info.code,
+                    info.data_size,
+                    info.offsets_size
                 );
             }
         }
diff --git a/drivers/android/binder/transaction.rs b/drivers/android/binder/transaction.rs
index afef5b46eac2..069c792d2200 100644
--- a/drivers/android/binder/transaction.rs
+++ b/drivers/android/binder/transaction.rs
@@ -404,6 +404,14 @@ fn do_work(
         } else {
             // On failure to process the list, we send a reply back to the sender and ignore the
             // transaction on the recipient.
+            binder_debug!(
+                FailedTransaction,
+                "transaction {} to {} failed, fd fixups failed, size {}-{}",
+                self.debug_id,
+                self.to.task.pid(),
+                self.data_size,
+                self.offsets_size
+            );
             return Ok(true);
         };
 

-- 
2.55.0.229.g6434b31f56-goog