Messages in this thread | | | Date | Tue, 30 Mar 2004 00:45:26 +0200 | From | Andrea Arcangeli <> | Subject | Re: 2.6.5-rc2-aa5 |
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On Mon, Mar 29, 2004 at 12:48:03PM -0800, Andrew Morton wrote: > Andrea Arcangeli <andrea@suse.de> wrote: > > > > Notably there is a BUG_ON(page->mapping) triggering in > > page_remove_rmap in the pagecache case. that could be ex-pagecache being > > removed from pagecache before all ptes have been zapped, infact the > > page_remove_rmap triggers in the vmtruncate path. > > Confused. vmtruncate zaps the ptes before removing pages from pagecache, > so I'd expect a non-null ->mapping in page_remove_rmap() is a very common
the bugcheck was for NULL ->mapping in page_remove_rmap:
BUG_ON(!page->mapping);
I tend to forget the ! in the pseudocode in emails sorry (today I did it twice, luckily I didn't get it wrong in the actual patches ;).
> thing. truncate a file which someone has mmapped and it'll happen every > time, will it not?
as you say vmtruncate zaps the pte _first_, so the page->mapcount should be down to 0 by the time we set page->mapping = NULL.
the thing I was wondering about is the controlled race where some page can go out of pagecache despite still being mapped somewhere, that could happen in the past IIRC. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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