Index: mesa-19.1.0/src/glx/drisw_glx.c
===================================================================
--- mesa-19.1.0.orig/src/glx/drisw_glx.c	2019-06-11 15:12:51.000000000 +0000
+++ mesa-19.1.0/src/glx/drisw_glx.c	2019-09-12 09:50:31.411325087 +0000
@@ -84,10 +84,12 @@ static Bool
 XCreateDrawable(struct drisw_drawable * pdp, int shmid, Display * dpy)
 {
    if (pdp->ximage) {
       XDestroyImage(pdp->ximage);
       pdp->ximage = NULL;
+      if ((pdp->shminfo.shmid > 0) && ( shmid != pdp->shminfo.shmid))
+	XShmDetach(dpy, &pdp->shminfo);
    }
 
    if (!xshm_error && shmid >= 0) {
       pdp->shminfo.shmid = shmid;
       pdp->ximage = XShmCreateImage(dpy,