Re: [PATCH] rust_binder: avoid name mangling for get_work[_local]

[gary@garyguo.net]

(Sorry Alice, resending as I didn't hit "Reply All". I was travelling 
and not on my usual email setup).

On 2026-02-13 11:37, Alice Ryhl wrote:
> Currently ps -A shows processes waiting on schedule() in functions with
> names such as do_epoll_wait, wait_woken, and the impeccably named
> _RNvMs2_NtCs8QPsHWIn21X_16rust_binder_main6threadNtB5_6Thread8get_work.
> 
> To improve how ps output looks, give explicit non-mangled names to the
> functions where Rust Binder calls schedule(), since these are the most
> likely places to show up on ps output.
> 
> The name of rust_binder_waitlcl is truncated instead of using _local
> suffix because rust_binder_wait_local is sufficiently long that ps 
> shows
> unaligned output.
> 
> Suggested-by: Matthew Maurer <mmaurer@google.com>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>

I don't think this the direction that we should head for. It's not 
feasible to
do this for all users that can possibly call `schedule()`. In edition 
2024
forwards, `export_name` is also an unsafe attribute and it will become 
tedious to
justify all usages.

I think if the function names are demangled, it won't be too bad?

Best,
Gary


> ---
>  drivers/android/binder/process.rs | 1 +
>  drivers/android/binder/thread.rs  | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/drivers/android/binder/process.rs 
> b/drivers/android/binder/process.rs
> index 
> 132055b4790f0ec69a87635b498909df2bf475e2..cf7425e74183966063ab53114637aec7b3672ac8 
> 100644
> --- a/drivers/android/binder/process.rs
> +++ b/drivers/android/binder/process.rs
> @@ -1436,6 +1436,7 @@ pub(crate) fn drop_outstanding_txn(&self) {
>          }
>      }
> 
> +    #[export_name = "rust_binder_freeze"]
>      pub(crate) fn ioctl_freeze(&self, info: &BinderFreezeInfo) -> 
> Result {
>          if info.enable == 0 {
>              let msgs = self.prepare_freeze_messages()?;
> diff --git a/drivers/android/binder/thread.rs 
> b/drivers/android/binder/thread.rs
> index 
> 1f1709a6a77abc1c865cc9387e7ba7493448c71d..2ca8ed8962314b58a3cfeb3ae0aa0ed60f179433 
> 100644
> --- a/drivers/android/binder/thread.rs
> +++ b/drivers/android/binder/thread.rs
> @@ -514,6 +514,7 @@ pub(crate) fn has_current_transaction(&self) -> 
> bool {
>      /// Attempts to fetch a work item from the thread-local queue. The 
> behaviour if the queue is
>      /// empty depends on `wait`: if it is true, the function waits for 
> some work to be queued (or a
>      /// signal); otherwise it returns indicating that none is 
> available.
> +    #[export_name = "rust_binder_waitlcl"]
>      fn get_work_local(self: &Arc<Self>, wait: bool) -> 
> Result<Option<DLArc<dyn DeliverToRead>>> {
>          {
>              let mut inner = self.inner.lock();
> @@ -552,6 +553,7 @@ fn get_work_local(self: &Arc<Self>, wait: bool) -> 
> Result<Option<DLArc<dyn Deliv
>      ///
>      /// This must only be called when the thread is not participating 
> in a transaction chain. If it
>      /// is, the local version (`get_work_local`) should be used 
> instead.
> +    #[export_name = "rust_binder_wait"]
>      fn get_work(self: &Arc<Self>, wait: bool) -> 
> Result<Option<DLArc<dyn DeliverToRead>>> {
>          // Try to get work from the thread's work queue, using only a 
> local lock.
>          {
> 
> ---
> base-commit: cee73b1e840c154f64ace682cb477c1ae2e29cc4
> change-id: 20260213-rust-binder-ps-46d9d060243a
> 
> Best regards,