rust_binder: track caller location in BinderError

Record the caller's location in BinderError using #[track_caller] and a
new ErrorLocation wrapper around &'static Location<'static> across all
BinderError constructors and From implementations. ErrorLocation
implements Display by stripping the directory prefix so locations are
formatted as filename.rs:line (e.g. process.rs:422).

In Context::get_manager_node and Process::buffer_alloc, avoid passing
BinderError::new_dead() or BinderError::from() as function pointers to
Option::ok_or_else() and Result::map_err() so that #[track_caller]
captures the call site in rust_binder correctly.

Include the error location in the FailedTransaction debug print and
prepare for recording it in the binder transaction log. Example output:

  rust_binder: 840:4583 transaction async to 7656:0 failed ESRCH, code 1 size 428-16 line thread.rs:711

Assisted-by: LLM
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260930-binder-transaction-log-v2-2-8a15e9b8cae3@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/android/binder/thread.rs b/drivers/android/binder/thread.rs
index b5dece7d2285..78dc0ca6f630 100644
--- a/drivers/android/binder/thread.rs
+++ b/drivers/android/binder/thread.rs
@@ -1340,7 +1340,7 @@ impl Thread {
 
                     binder_debug!(
                         FailedTransaction,
-                        "transaction {} to {}:{} failed {:?}, code {} size {}-{}",
+                        "transaction {} to {}:{} failed {:?}, code {} size {}-{} line {}",
                         if info.is_reply {
                             "reply"
                         } else if info.is_oneway() {
@@ -1353,7 +1353,8 @@ impl Thread {
                         err,
                         info.code,
                         info.data_size,
-                        info.offsets_size
+                        info.offsets_size,
+                        err.line
                     );
                 }
             }