Messages in this thread | | | Subject | Re: [patch 2.6.13-rc4] fix get_user_pages bug | From | Martin Schwidefsky <> | Date | Tue, 2 Aug 2005 14:01:29 +0200 |
| |
> > Any chance you can change the __follow_page test to account for > > writeable clean ptes? Something like > > > > if (write && !pte_dirty(pte) && !pte_write(pte)) > > goto out; > > > > And then you would re-add the set_page_dirty logic further on. > > Hmm.. That should be possible. I wanted to do the simplest possible code > sequence, but yeah, I guess there's nothing wrong with allowing the code > to dirty the page. > > Somebody want to send me a proper patch? Also, I haven't actually heard > from whoever actually noticed the problem in the first place (Robin?) > whether the fix does fix it. It "obviously does", but testing is always > good ;)
Why do we require the !pte_dirty(pte) check? I don't get it. If a writeable clean pte is just fine then why do we check the dirty bit at all? Doesn't pte_dirty() imply pte_write()?
With the additional !pte_write(pte) check (and if I haven't overlooked something which is not unlikely) s390 should work fine even without the software-dirty bit hack.
blue skies, Martin
Martin Schwidefsky Linux for zSeries Development & Services IBM Deutschland Entwicklung GmbH
- 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/
| |