From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jahnavi MN <jahnavimn@google.com>
Date: Thu, 16 Jul 2026 08:37:47 +0000
Subject: [PATCH v4 5/7] rust_binder: Implement
 BINDER_DEBUG_FAILED_TRANSACTION
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Message-Id: <20260716-rust_binder_debug_mask-v4-5-3d7436c2d2f2@google.com>
References: <20260716-rust_binder_debug_mask-v4-0-3d7436c2d2f2@google.com>
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To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
 =?utf-8?q?Arve_Hj=C3=B8nnev=C3=A5g?= <arve@android.com>, 
 Todd Kjos <tkjos@android.com>, Christian Brauner <brauner@kernel.org>, 
 Carlos Llamas <cmllamas@google.com>, Alice Ryhl <aliceryhl@google.com>, 
 Miguel Ojeda <ojeda@kernel.org>, Boqun Feng <boqun@kernel.org>, 
 Gary Guo <gary@garyguo.net>, 
 =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>, 
 Benno Lossin <lossin@kernel.org>, Andreas Hindborg <a.hindborg@kernel.org>, 
 Trevor Gross <tmgross@umich.edu>, Danilo Krummrich <dakr@kernel.org>, 
 Daniel Almeida <daniel.almeida@collabora.com>, 
 Tamir Duberstein <tamird@kernel.org>, 
 Alexandre Courbot <acourbot@nvidia.com>, 
 =?utf-8?q?Onur_=C3=96zkan?= <work@onurozkan.dev>
Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, 
 Jahnavi MN <jahnavimn@google.com>
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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