--- modules/http/http_filters.c	(revision 1522486)
+++ modules/http/http_filters.c	(working copy)
@@ -353,6 +353,9 @@ apr_status_t ap_http_filter(ap_filter_t *f, apr_bu
             }
 
             if (rv != APR_SUCCESS) {
+                if (rv == APR_EOF) {
+                    return APR_INCOMPLETE;
+                }
                 return rv;
             }
 
@@ -410,6 +413,10 @@ apr_status_t ap_http_filter(ap_filter_t *f, apr_bu
                 }
 
                 if (rv != APR_SUCCESS) {
+                    if (rv == APR_EOF && ctx->remaining > 0 &&
+                            ctx->state != BODY_NONE) {
+                        return APR_INCOMPLETE;
+                    }
                     return rv;
                 }
 
@@ -474,6 +481,9 @@ apr_status_t ap_http_filter(ap_filter_t *f, apr_bu
             }
 
             if (rv != APR_SUCCESS) {
+                if (rv == APR_EOF) {
+                    return APR_INCOMPLETE;
+                }
                 return rv;
             }
 
--- modules/http/chunk_filter.c	(revision 1522486)
+++ modules/http/chunk_filter.c	(working copy)
@@ -72,15 +72,17 @@ apr_status_t ap_http_chunk_filter(ap_filter_t *f,
                 eos = e;
                 break;
             }
-            if (AP_BUCKET_IS_ERROR(e)
-                && (((ap_bucket_error *)(e->data))->status
-                    == HTTP_BAD_GATEWAY)) {
-                /*
-                 * We had a broken backend. Memorize this in the filter
-                 * context.
-                 */
-                f->ctx = &bad_gateway_seen;
-                continue;
+            if (AP_BUCKET_IS_ERROR(e)) {
+                switch (((ap_bucket_error *)(e->data))->status) {
+                case HTTP_BAD_GATEWAY:
+                case HTTP_GATEWAY_TIME_OUT:
+                    /*
+                     * We had a broken backend. Memorize this in the filter
+                     * context.
+                     */
+                    f->ctx = &bad_gateway_seen;
+                    continue;
+                }
             }
             if (APR_BUCKET_IS_FLUSH(e)) {
                 flush = e;