On Sat, Oct 04, 2014 at 05:00:36PM +0900, Kohji Okuno wrote: > Hi, Konstantin, > > Thank you for your comment. > And, your change is better than mine. At the end of the mail is commit candidate. I did not even compiled this. Can you test and report back, please ? > > > Do you mean that this panic is related to missed pmap_remove() ? > > I doubt it, since pmap_mapdev() does not establish managed mappings. > > Yes, pmap_mapdev() does not establish managed mappings. But, if > kernel_pmap.pm_stats.resident_count is zero, then any managed pages > (for example pipe_map, exec_map, or etc.) are not able to change > unmanaged status, because pmap_remove() returns without calling > pmap_remove_pte(). > > In this result, I encounterd the panic. Could you refer the following? Yes, kmem_back() indeed uses managed mapping. Index: amd64/amd64/pmap.c =================================================================== --- amd64/amd64/pmap.c (revision 272506) +++ amd64/amd64/pmap.c (working copy) _at__at_ -5040,6 +5040,9 _at__at_ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, in pa = trunc_page(pa); for (tmpsize = 0; tmpsize < size; tmpsize += PAGE_SIZE) pmap_kenter_attr(va + tmpsize, pa + tmpsize, mode); + PMAP_LOCK(kernel_pmap); + kernel_pmap.pm_stats.resident_count += OFF_TO_IDX(size); + PMAP_UNLOCK(kernel_pmap); pmap_invalidate_range(kernel_pmap, va, va + tmpsize); pmap_invalidate_cache_range(va, va + tmpsize); return ((void *)(va + offset)); Index: i386/i386/pmap.c =================================================================== --- i386/i386/pmap.c (revision 272506) +++ i386/i386/pmap.c (working copy) _at__at_ -5066,10 +5066,14 _at__at_ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, in size = roundup(offset + size, PAGE_SIZE); pa = pa & PG_FRAME; - if (pa < KERNLOAD && pa + size <= KERNLOAD) + if (pa < KERNLOAD && pa + size <= KERNLOAD) { va = KERNBASE + pa; - else + } else { va = kmem_alloc_nofault(kernel_map, size); + PMAP_LOCK(kernel_pmap); + kernel_pmap.pm_stats.resident_count += OFF_TO_IDX(size); + PMAP_UNLOCK(kernel_pmap); + } if (!va) panic("pmap_mapdev: Couldn't alloc kernel virtual memory");Received on Sat Oct 04 2014 - 06:29:48 UTC
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