Bug 296822 NullProgressMonitor is not thread safe for expected usage
NullProgressMonitor.setCanceled and isCanceled access the cancelled field, but there's no synchronization. The expected use is that setCanceled is called from a thread other than the one doing the work, which polls isCanceled(), so this needs to be thread safe. Could either make these two methods synchronized or make the field volatile. Should check other progress monitor implementations too.
bundles/org.eclipse.jface/src/org/eclipse/jface/action/StatusLine.java
private final StatusLineLayoutData DEFAULT_DATA = new StatusLineLayoutData();
		public Point computeSize(Composite composite, int wHint, int hHint,
				boolean changed) {
			if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT) {
				return new Point(wHint, hHint);
			}
			Control[] children = composite.getChildren();
			int totalWidth = 0;
			int maxHeight = 0;
			int totalCnt = 0;
			for (int i = 0; i < children.length; i++) {
				boolean useWidth = true;
				Control w = children[i];
				if (w == fProgressBarComposite && !fProgressIsVisible) {
					useWidth = false;
				} else if (w == fToolBar && !fCancelButtonIsVisible) {
					useWidth = false;
				}
				StatusLineLayoutData data = (StatusLineLayoutData) w
						.getLayoutData();
				if (data == null) {
					data = DEFAULT_DATA;
				}
				Point e = w.computeSize(data.widthHint, data.heightHint,
						changed);
				if (useWidth) {
					totalWidth += e.x;