Date: Wed, 11 Nov 2009 11:37:19 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>, Izik Eidus <ieidus@redhat.com>,
       Andrea Arcangeli <aarcange@redhat.com>,
       Minchan Kim <minchan.kim@gmail.com>, Andi Kleen <andi@firstfloor.org>,
       Wu Fengguang <fengguang.wu@intel.com>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org
Subject: Re: [PATCH 6/6] mm: sigbus instead of abusing oom
Message-Id: <20091111113719.589e61d7.kamezawa.hiroyu@jp.fujitsu.com>
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	<Pine.LNX.4.64.0911102202500.2816@sister.anvils>
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On Tue, 10 Nov 2009 22:06:49 +0000 (GMT)
Hugh Dickins <hugh.dickins@tiscali.co.uk> wrote:

> When do_nonlinear_fault() realizes that the page table must have been
> corrupted for it to have been called, it does print_bad_pte() and
> returns ... VM_FAULT_OOM, which is hard to understand.
> 
> It made some sense when I did it for 2.6.15, when do_page_fault()
> just killed the current process; but nowadays it lets the OOM killer
> decide who to kill - so page table corruption in one process would
> be liable to kill another.
> 
> Change it to return VM_FAULT_SIGBUS instead: that doesn't guarantee
> that the process will be killed, but is good enough for such a rare
> abnormality, accompanied as it is by the "BUG: Bad page map" message.
> 
> And recent HWPOISON work has copied that code into do_swap_page(),
> when it finds an impossible swap entry: fix that to VM_FAULT_SIGBUS too.
> 
> Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>

Thank you !
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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