Messages in this thread |  | | Date | Fri, 16 Feb 2007 09:30:12 -0500 (EST) | From | James Morris <> | Subject | Re: 2.6.20-mm1 [kernel BUG at mm/swap.c:442] |
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On Thu, 15 Feb 2007, Christoph Lameter wrote:
> On Thu, 15 Feb 2007, Andrew Morton wrote: > > > I don't immediately see why that code isn't racy: the page can remain > > in the pagevec for arbitrary amounts of time and someone can come along > > and mlock it again. But given the ease with which you're hitting this, > > it may not be a race. > > As long as the page is on the pagevec it should be off the LRU. > Marking a page PageMlocked requires the page to be on the LRU. So a page > cannot be marked PageMlocked as long as it is on the regular pagevecs. > > Somehow a page off the LRU was marked PageMlocked. Or a new anonymous page > was allocated and marked PageMlocked and then some later processing put it > onto the LRU? > > Maybe try_to_set_mlocked does work some havoc here. > > Could you see if this patch fixes it? This just disabled an optimization > to set PageMlocked early.
Nope, doesn't fix the problem.
> Index: linux-2.6.20-mm1/mm/memory.c > =================================================================== > --- linux-2.6.20-mm1.orig/mm/memory.c 2007-02-15 14:35:41.000000000 -0800 > +++ linux-2.6.20-mm1/mm/memory.c 2007-02-15 14:35:54.000000000 -0800 > @@ -930,6 +930,8 @@ static void try_to_set_mlocked(struct pa > struct zone *zone; > unsigned long flags; > > + return; > + > if (!PageLRU(page) || PageMlocked(page)) > return; > >
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