Fix process handle leak when launching a job container

kevpar · kevpar · commit 976716ed6294 · 2024-02-07T22:03:38.000-08:00
CreateProcess gives us back a handle to the newly created process.
Previously, we ignored this handle, which meant it was leaking every
time we created a new job container (or anything else that uses
internal/exec in the future).

Process handle leaks can be bad as an exited process is left as a
"zombie" until all handles to it have closed, continuing to use memory.

Fix this by closing the handle from CreateProcess.

Signed-off-by: Kevin Parsons &lt;kevpar@microsoft.com&gt;
diff --git a/internal/exec/exec.go b/internal/exec/exec.go
@@ -209,8 +209,8 @@ func (e *Exec) Start() error {
 	if err != nil {
 		return fmt.Errorf("failed to create process: %w", err)
 	}
-	// Don't need the thread handle for anything.
 	defer func() {
+		_ = windows.CloseHandle(windows.Handle(pi.Process))
 		_ = windows.CloseHandle(windows.Handle(pi.Thread))
 	}()
 

Original file line number	Diff line number	Diff line change
`@@ -209,8 +209,8 @@ func (e *Exec) Start() error {`
`209`	`209`	`if err != nil {`
`210`	`210`	`return fmt.Errorf("failed to create process: %w", err)`
`211`	`211`	`}`
`212`		`- // Don't need the thread handle for anything.`
`213`	`212`	`defer func() {`
	`213`	`+ _ = windows.CloseHandle(windows.Handle(pi.Process))`
`214`	`214`	`_ = windows.CloseHandle(windows.Handle(pi.Thread))`
`215`	`215`	`}()`
`216`	`216`