On Tue, 23 Oct 2012 12:21:53 +0200 Jan Kara <jack@xxxxxxx> wrote: > > That seems a fairly serious problem. To which kernel version(s) should > > we apply the fix? > Well, XFS will crash starting from 2.6.36 kernel where the assertion was > added. Previously XFS just silently added buffers (as other filesystems do > it) and wrote / redirtied the page (unnecessarily). So looking into > maintained -stable branches I think pushing the patch to -stable from 3.0 > on should be enough. OK, thanks, I made it so. > > > diff --git a/mm/rmap.c b/mm/rmap.c > > > > It's a bit surprising that none of the added comments mention the s390 > > pte-dirtying oddity. I don't see an obvious place to mention this, but > > I for one didn't know about this and it would be good if we could > > capture the info _somewhere_? > As Hugh says, the comment before page_test_and_clear_dirty() is somewhat > updated. But do you mean recording somewhere the catch that s390 HW dirty > bit gets set also whenever we write to a page from kernel? Yes, this. It's surprising behaviour which we may trip over again, so how do we inform developers about it? > I guess we could > add that also to the comment before page_test_and_clear_dirty() in > page_remove_rmap() and also before definition of > page_test_and_clear_dirty(). So most people that will add / remove these > calls will be warned. OK? Sounds good, thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>