-diff -urN mesa-18.1.2.orig/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c mesa-18.1.2/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
---- mesa-18.1.2.orig/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c 2018-07-04 12:45:31.057803594 +0200
-+++ mesa-18.1.2/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c 2018-07-04 12:47:02.030220461 +0200
-@@ -368,10 +368,14 @@
- DEBUG_PRINT("KMS-DEBUG: unmapped buffer %u (was %p)\n", kms_sw_dt->handle, kms_sw_dt->mapped);
- DEBUG_PRINT("KMS-DEBUG: unmapped buffer %u (was %p)\n", kms_sw_dt->handle, kms_sw_dt->ro_mapped);
-
-- munmap(kms_sw_dt->mapped, kms_sw_dt->size);
-- kms_sw_dt->mapped = NULL;
-- munmap(kms_sw_dt->ro_mapped, kms_sw_dt->size);
-- kms_sw_dt->ro_mapped = NULL;
-+ if (kms_sw_dt->mapped != NULL) {
-+ munmap(kms_sw_dt->mapped, kms_sw_dt->size);
-+ kms_sw_dt->mapped = NULL;
-+ }
-+ if (kms_sw_dt->ro_mapped != NULL) {
-+ munmap(kms_sw_dt->ro_mapped, kms_sw_dt->size);
-+ kms_sw_dt->ro_mapped = NULL;
-+ }
- }
-
- static struct sw_displaytarget *