sort_iter_sort(iter, sort_keys_cmp);
 
        while ((in = sort_iter_next(iter, sort_keys_cmp))) {
+               bool needs_whiteout = false;
+
                if (bkey_whiteout(in) &&
                    (filter_whiteouts || !in->needs_whiteout))
                        continue;
 
-               if (bkey_whiteout(in) &&
-                   (next = sort_iter_peek(iter)) &&
-                   !bkey_cmp_packed(iter->b, in, next)) {
+               while ((next = sort_iter_peek(iter)) &&
+                      !bkey_cmp_packed(iter->b, in, next)) {
                        BUG_ON(in->needs_whiteout &&
                               next->needs_whiteout);
-                       /*
-                        * XXX racy, called with read lock from write path
-                        *
-                        * leads to spurious BUG_ON() in bkey_unpack_key() in
-                        * debug mode
-                        */
-                       next->needs_whiteout |= in->needs_whiteout;
-                       continue;
+                       needs_whiteout |= in->needs_whiteout;
+                       in = sort_iter_next(iter, sort_keys_cmp);
                }
 
                if (bkey_whiteout(in)) {
                } else {
                        bkey_copy(out, in);
                }
+               out->needs_whiteout |= needs_whiteout;
                out = bkey_next(out);
        }
 
 
                if (btree_keys_expensive_checks(b)) {
                        struct bkey dst2 = __bch2_bkey_unpack_key(&b->format, src);
 
-                       /*
-                        * hack around a harmless race when compacting whiteouts
-                        * for a write:
-                        */
-                       dst2.needs_whiteout = dst->needs_whiteout;
-
                        BUG_ON(memcmp(dst, &dst2, sizeof(*dst)));
                }
        }
 
                if (debug_check_iterators(iter->trans->c)) {
                        struct bkey k = bkey_unpack_key(l->b, _k);
 
-                       /*
-                        * this flag is internal to the btree code,
-                        * we don't care if it doesn't match - if it's now set
-                        * it just means the key has been written out to disk:
-                        */
-                       k.needs_whiteout = iter->k.needs_whiteout;
                        BUG_ON(memcmp(&k, &iter->k, sizeof(k)));
                }