On 06/04/16 15:02, Konstantin Belousov wrote: > On Sat, Jun 04, 2016 at 02:59:01PM -0400, Michael Butler wrote: >> On 06/04/16 13:47, Konstantin Belousov wrote: >> >> [ .. snip .. ] >> >>> I believe that this is a bug in amd64 pmap. Fictitious pages are not >>> promoted, in particular, the pv_table array does not span over the >>> dynamically registered fictitious ranges. As result, pa_to_pvh() returns >>> garbage and pvh must not be accessed in the case of 'small_mappings' in >>> several pmap functions. It is typically not accessed, except in case >>> when we have to drop and reacquire pv lock, to avoid LOR with pmap. >>> >>> i386 does not have the issue, due to pvh_global_lock. >>> >>> Below is the supposed fix (not tested). >> >> [ .. snip .. ] >> >> Is this something I should test and, should it not introduce any other >> issues, might get committed? > > Would be nice to test. I expect that this patch is going to be committed, > after the review. > I will do so this evening and add a kprintf to the previous band-aid to see if it prevents the problematic condition from occurring. If it counts, my test laptop has a Core-2 Duo so it is entirely possible that multiple threads are running concurrently, imbReceived on Sat Jun 04 2016 - 17:11:24 UTC
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