Comment 2 for bug 1231207

StacktraceTop:
 list_add (head=0x18, entry=0x7fd1aa11a148) at ../../../src/intel_list.h:161
 list_move (head=0x18, list=0x7fd1aa11a148) at ../../../src/intel_list.h:248
 __kgem_bo_mark_dirty (bo=0x7fd1aa11a120) at ../../../src/sna/kgem.h:686
 kgem_add_reloc (kgem=kgem@entry=0x7fd1a8fe2000, pos=<optimized out>, bo=bo@entry=0x7fd1aa11a120, read_write_domain=read_write_domain@entry=163842, delta=<optimized out>, delta@entry=0) at ../../../src/sna/kgem.c:4798
 sna_blt_copy_boxes (sna=sna@entry=0x7fd1a8fe2000, alu=<optimized out>, src_bo=src_bo@entry=0x7fd1aa11a240, src_dx=src_dx@entry=0, src_dy=src_dy@entry=0, dst_bo=dst_bo@entry=0x7fd1aa11a120, dst_dx=dst_dx@entry=0, dst_dy=dst_dy@entry=0, bpp=32, box=box@entry=0x7fffb4db36d0, nbox=0, nbox@entry=1) at ../../../src/sna/sna_blt.c:2925