Message-ID: <47B19628.8090003@movial.fi>
Date: Tue, 12 Feb 2008 14:50:48 +0200
From: Riku Voipio <riku.voipio@movial.fi>
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To: Thomas Gleixner <tglx@linutronix.de>
CC: Adrian Bunk <adrian.bunk@movial.fi>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org, Mikael Pettersson <mikpe@it.uu.se>,
       Lennert Buytenhek <buytenh@wantstofly.org>,
       Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: futex local DoS on most architectures
References: <20080211130700.GF27537@movial.fi> <alpine.LFD.1.00.0802111442130.12988@apollo.tec.linutronix.de>
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Thomas Gleixner wrote:
> We have to disable the complete PI/robust functionality for those
> archs, which do not implement futex_atomic_cmpxchg_inatomic(). The
> code in question relies on a valid implementation and does not expect
> -ENOSYS, which is returned by the stub implementation in
> asm-generic/futex.h
>
> Pointed out by: Mikael Pettersson, Riku Voipio and Adrian Bunk
>   
Original credits for finding this issue belong to Lennert Buytenhek.
> This patch is intended for easy backporting and needs to be cleaned up
> further for current mainline.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Acked-by: Ingo Molnar <mingo@elte.hu>
Looks good for me and kernel no longer deadlocks with this patch!
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