Messages in this thread | | | Date | Wed, 9 Jul 2014 01:15:06 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [PATCH] mm: Don't forget to set softdirty on file mapped fault |
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On Tue, Jul 08, 2014 at 02:05:01PM -0700, Andrew Morton wrote: > > > > In case if page fault happend on dirty filemapping the newly created pte > > may loose softdirty bit thus if a userspace program is tracking memory > > changes with help of a memory tracker (CONFIG_MEM_SOFT_DIRTY) it might > > miss modification of a memory page (which in worts case may lead to > > data inconsistency). > > Much better, thanks. > > It's a rather gross-looking bug and data inconsistency sounds serious. > Do you think a -stable backport is needed?
It seems the memory tracker is not that widespread in userspace programs (I mean at the moment as far as I know only we use it intensively) so I don't consider it as critical but moving it into stable won't hurt. Still I fear in 3.16 the mm/memory.c code has been significantly reworked so this patch won't apply on its own. I can prepare a patch for 3.15 though, just say a word.
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