| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 11 Nov 2008 21:10:45 -0600 (CST) From: Christoph Lameter <cl@...ux-foundation.org> To: Andrea Arcangeli <aarcange@...hat.com> cc: Andrew Morton <akpm@...ux-foundation.org>, Izik Eidus <ieidus@...hat.com>, linux-kernel@...r.kernel.org, linux-mm@...ck.org, kvm@...r.kernel.org, chrisw@...hat.com, avi@...hat.com, izike@...ranet.com Subject: Re: [PATCH 2/4] Add replace_page(), change the mapping of pte from one page into another On Wed, 12 Nov 2008, Andrea Arcangeli wrote: > So are you checking if there's an unresolved reference only in the > very place I just quoted in the previous email? If answer is yes: what > should prevent get_user_pages from running in parallel from another > thread? get_user_pages will trigger a minor fault and get the elevated > reference just after you read page_count. To you it looks like there > is no o_direct in progress when you proceed to the core of migration > code, but in effect o_direct just started a moment after you read the > page count. get_user_pages() cannot get to it since the pagetables have already been modified. If get_user_pages runs then the fault handling will occur which will block the thread until migration is complete. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists