[pbs-devel] applied: [PATCH proxmox-backup v2] api2/node/termproxy: fix zombies on worker abort
Wolfgang Bumiller
w.bumiller at proxmox.com
Thu Jul 30 10:39:44 CEST 2020
applied
On Wed, Jul 29, 2020 at 01:50:27PM +0200, Dominik Csapak wrote:
> tokios kill_on_drop sometimes leaves zombies around, especially
> when there is not another tokio::process::Command spawned after
>
> so instead of relying on the 'kill_on_drop' feature, we explicitly
> kill the child on a worker abort. to be able to do this
> we have to use 'tokio::select' instead of 'futures::select' since
> the latter requires the future to be fused, which consumes the
> child handle, leaving us no possibility to kill it after fusing.
> (tokio::select does not need the futures to be fused, so we
> can reuse the child future after the select again)
>
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
> changes from v1:
> * if the worker future is ok, bubble errors up from child kill/await
> if the worker future is err, log errors from kill/await and return
> the error from the abort
> src/api2/node.rs | 36 ++++++++++++++++++++++++++----------
> 1 file changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/src/api2/node.rs b/src/api2/node.rs
> index 9be5fe6d..5a3ea0ff 100644
> --- a/src/api2/node.rs
> +++ b/src/api2/node.rs
> @@ -2,10 +2,7 @@ use std::net::TcpListener;
> use std::os::unix::io::AsRawFd;
>
> use anyhow::{bail, format_err, Error};
> -use futures::{
> - future::{FutureExt, TryFutureExt},
> - select,
> -};
> +use futures::future::{FutureExt, TryFutureExt};
> use hyper::body::Body;
> use hyper::http::request::Parts;
> use hyper::upgrade::Upgraded;
> @@ -172,7 +169,6 @@ async fn termproxy(
> let mut cmd = tokio::process::Command::new("/usr/bin/termproxy");
>
> cmd.args(&arguments)
> - .kill_on_drop(true)
> .stdout(std::process::Stdio::piped())
> .stderr(std::process::Stdio::piped());
>
> @@ -199,8 +195,9 @@ async fn termproxy(
> Ok::<(), Error>(())
> };
>
> - select!{
> - res = child.fuse() => {
> + let mut needs_kill = false;
> + let res = tokio::select!{
> + res = &mut child => {
> let exit_code = res?;
> if !exit_code.success() {
> match exit_code.code() {
> @@ -210,10 +207,29 @@ async fn termproxy(
> }
> Ok(())
> },
> - res = stdout_fut.fuse() => res,
> - res = stderr_fut.fuse() => res,
> - res = worker.abort_future().fuse() => res.map_err(Error::from),
> + res = stdout_fut => res,
> + res = stderr_fut => res,
> + res = worker.abort_future() => {
> + needs_kill = true;
> + res.map_err(Error::from)
> + }
> + };
> +
> + if needs_kill {
> + if res.is_ok() {
> + child.kill()?;
> + child.await?;
> + return Ok(());
> + }
> +
> + if let Err(err) = child.kill() {
> + worker.warn(format!("error killing termproxy: {}", err));
> + } else if let Err(err) = child.await {
> + worker.warn(format!("error awaiting termproxy: {}", err));
> + }
> }
> +
> + res
> },
> )?;
>
> --
> 2.20.1
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