Fix race condition in CleanupGVProxy when reading gvproxy PID file

When startVM fails quickly, CleanupGVProxy may attempt to read the
gvproxy.pid file before gvproxy has written it, causing cleanup to
fail.

This commit adds retry logic that waits up to 2 seconds for the PID
file to appear.

Signed-off-by: lstocchi <lstocchi@redhat.com>

pkg/machine/gvproxy.go

@@ -5,13 +5,37 @@ import (
 	"fmt"
 	"io/fs"
 	"strconv"
+	"time"
 
 	"github.com/containers/podman/v6/pkg/machine/define"
 )
 
+const (
+	pidFileWaitTimeout   = 2 * time.Second
+	pidFileCheckInterval = 50 * time.Millisecond
+)
+
+func readPIDFileWithRetry(f define.VMFile) ([]byte, error) {
+	deadline := time.Now().Add(pidFileWaitTimeout)
+
+	for time.Now().Before(deadline) {
+		gvPid, err := f.Read()
+		if err == nil {
+			return gvPid, nil
+		}
+		if !errors.Is(err, fs.ErrNotExist) {
+			return nil, err
+		}
+		time.Sleep(pidFileCheckInterval)
+	}
+
+	// Final attempt after timeout
+	return f.Read()
+}
+
 // CleanupGVProxy reads the --pid-file for gvproxy attempts to stop it
 func CleanupGVProxy(f define.VMFile) error {
-	gvPid, err := f.Read()
+	gvPid, err := readPIDFileWithRetry(f)
 	if err != nil {
 		// The file will also be removed by gvproxy when it exits so
 		// we need to account for the race and can just ignore it here.