binder: Remove bogus warning on failed same-process transaction

While binder transactions with the same binder_proc as sender and recipient
are forbidden, transactions with the same task_struct as sender and
recipient are possible (even though currently there is a weird check in
binder_transaction() that rejects them in the target==0 case).
Therefore, task_struct identities can't be used to distinguish whether
the caller is running in the context of the sender or the recipient.

Since I see no easy way to make this WARN_ON() useful and correct, let's
just remove it.

Fixes: 44d8047 ("binder: use standard functions to allocate fds")
Reported-by: [email protected]
Acked-by: Christian Brauner <[email protected]>
Acked-by: Todd Kjos <[email protected]>
Signed-off-by: Jann Horn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/android/binder.c

@@ -2344,8 +2344,6 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
 			 * file is done when the transaction is torn
 			 * down.
 			 */
-			WARN_ON(failed_at &&
-				proc->tsk == current->group_leader);
 		} break;
 		case BINDER_TYPE_PTR:
 			/*