linux-kernel - Re: [PATCH 13/12] ksm: fix munlock during exit

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.00.0908261457140.12052@chino.kir.corp.google.com>
Date:	Wed, 26 Aug 2009 15:00:12 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Andrea Arcangeli <aarcange@...hat.com>
cc:	Izik Eidus <ieidus@...hat.com>,
	Hugh Dickins <hugh.dickins@...cali.co.uk>,
	Rik van Riel <riel@...hat.com>,
	Chris Wright <chrisw@...hat.com>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Justin M. Forbes" <jmforbes@...uxtx.org>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 13/12] ksm: fix munlock during exit_mmap deadlock

On Wed, 26 Aug 2009, Andrea Arcangeli wrote:

> In oom deadlock terms madvise(UNMERGEABLE) is the only place that is
> 100% fine at breaking KSM pages, because it runs with right tsk->mm
> and page allocation will notice TIF_MEMDIE set on tsk.
> 

Be aware that the page allocator in Linus' git will not notice TIF_MEMDIE 
for current if that task is chosen for oom kill since alloc_flags are not 
updated for that particular allocation.  My patch in -mm,
mm-update-alloc_flags-after-oom-killer-has-been-called.patch, fixes that 
but is not yet merged (I assume it's on hold for 2.6.32?).

I'd hate for you to run into this in testing and spend time debugging it 
when the problem already has a fix.
--
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/