> panic: kernel diagnostic assertion "me" failed: file "/usr/src/sys/uvm/uvm_map.c", line 481

> db{0}> trace
> cpu_Debugger(0xf02874a0, 0xf0254fa8, 0xf0268790, 0xf0277ef8, 0x100, 0xf02a4c00) at netbsd:__assert+0x18
> __assert(0xf0254fa8, 0xf0277ef8, 0x1e1, 0xf0268790, 0x0, 0x0) at netbsd:uvm_map_clip_end+0x2a0
> uvm_map_clip_end(0xf02c44d8, 0xf08f31f8, 0xf4300000, 0xf00, 0x40500, 0xf42e5000) at netbsd:uvm_unmap_remove+0x388
> uvm_unmap_remove(0xf02c44d8, 0xf42e5000, 0xf4300000, 0xf029f04c, 0xf029f050, 0xffffffff) at netbsd:uvm_unmap1+0xcc
> uvm_unmap1(0xf02c44d8, 0xf42e5000, 0xf4300000, 0xf02c4590, 0xffffffff, 0xc00000) at netbsd:_bus_dma_valloc_skewed+0xa4
> _bus_dma_valloc_skewed(0xf4300000, 0xf42e5000, 0x40000, 0x0, 0x0, 0xf08fe880) at netbsd:iommu_dmamem_map+0x50
> iommu_dmamem_map(0xf09fe900, 0xf029f1a8, 0x1, 0x65000, 0xf0a0f6c8, 0x5) at netbsd:hme_config+0x90

i think it's a symptom of PR/29117.
a workaround is to make _bus_dma_valloc_skewed use uvm_map directly
as -current does.

YAMAMOTO Takashi