==10268== Invalid read of size 4
==10268==    at 0xD04058: vert_mask_get (bmesh_log.c:171)
==10268==    by 0xD0462C: bm_log_vert_values_swap (bmesh_log.c:302)
==10268==    by 0xD084B0: BM_log_undo (bmesh_log.c:670)
==10268==    by 0xB20B55: sculpt_undo_bmesh_restore_generic (sculpt_undo.c:270)
==10268==    by 0xB20DED: sculpt_undo_bmesh_restore (sculpt_undo.c:361)
==10268==    by 0xB20F19: sculpt_undo_restore (sculpt_undo.c:398)
==10268==    by 0xAFC557: undo_restore (paint_undo.c:70)
==10268==    by 0xAFC885: undo_stack_step (paint_undo.c:163)
==10268==    by 0xAFCB91: ED_undo_paint_step (paint_undo.c:245)
==10268==    by 0x888ACE: ed_undo_step (undo.c:176)
==10268==    by 0x888E8A: ed_undo_exec (undo.c:274)
==10268==    by 0x6C1E09: wm_operator_invoke (wm_event_system.c:891)
==10268==    by 0x6C320C: wm_handler_operator_call (wm_event_system.c:1464)
==10268==    by 0x6C3AA3: wm_handlers_do_intern (wm_event_system.c:1732)
==10268==    by 0x6C3DE9: wm_handlers_do (wm_event_system.c:1839)
==10268==    by 0x6C4B34: wm_event_do_handlers (wm_event_system.c:2165)
==10268==    by 0x6BB66E: WM_main (wm.c:447)
==10268==    by 0x6BA9C6: main (creator.c:1579)
==10268==  Address 0x0 is not stack'd, malloc'd or (recently) free'd