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From: Andrew Morton <akpm@digeo.com>
To: "dada1" <dada1@cosmosbay.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Strong kernel lock with linux-2.5.59 : futex in Huge Pages
Date: Thu, 23 Jan 2003 01:41:45 -0800	[thread overview]
Message-ID: <20030123014145.633b6517.akpm@digeo.com> (raw)
In-Reply-To: <00e201c2c2c0$838954c0$760010ac@edumazet>

"dada1" <dada1@cosmosbay.com> wrote:
>
> Hello
> 
> I found a way to lock a linux-2.5.59 in all cases, in using futexes landing
> in a HugeTLB page.
> 
> You need to be root to be able to obtain HugePages (or CAP_IPC_LOCK
> capability)
> 
> I suspect that the kernel/futex.c:__pin_page(unsigned long addr) or
> mm/memory.c:follow_page() are not HugeTLB page aware.
> 
> How you can reproduce it. (dont do it of course, unless you really want to
> debug the thing)

Yup, futexes and direct-io against hugepages are bust.  I was going to fix
that up this week, but got distracted.



  reply	other threads:[~2003-01-23  9:32 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-01-23  8:52 OOPS in idescsi_end_request Andrey Borzenkov
2003-01-23  9:19 ` Strong kernel lock with linux-2.5.59 : futex in Huge Pages dada1
2003-01-23  9:41   ` Andrew Morton [this message]
2003-01-24  3:15 ` OOPS in idescsi_end_request Brian King
2003-01-24  6:21   ` Re[2]: " Andrey Borzenkov
2003-01-24  9:06     ` James Stevenson
2003-01-24 13:39       ` Brian King

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