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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@osdl.org>,
	linuxppc-dev list <linuxppc-dev@ozlabs.org>,
	Paul Mackerras <paulus@samba.org>,
	Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] powerpc vdso updates
Date: Tue, 30 May 2006 17:21:40 +1000	[thread overview]
Message-ID: <1148973700.15722.34.camel@localhost.localdomain> (raw)
In-Reply-To: <20060530062447.GD19870@elte.hu>


> get_unmapped_area() without holding the mmap semaphore seems dangerous. 
> The VDSO setup itself should be 'private' to the process, but i'm not 
> totally sure that no other kernel code could get access to this mm. For 
> example the swapout code? Am i missing something?

Well, all of this happens so early, I doubt anything will cause actual
harm, for get_unmapped_area to be a problem, something would have to
concurrently allocate a VMA (or dispose of) I think that can't happen at
this point before we even run the binary but yes, better safe than
sorry... I supose the whole patch could get in 2.6.17 even without the
arch_vma_name (that is it can be there, it wont be used though until
your patch gets in).

Ben.

  reply	other threads:[~2006-05-30  7:22 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-30  3:51 [PATCH] powerpc vdso updates Benjamin Herrenschmidt
2006-05-30  6:24 ` Ingo Molnar
2006-05-30  7:21   ` Benjamin Herrenschmidt [this message]
2006-06-10  3:15 ` Anton Blanchard
2006-06-10  6:30   ` Benjamin Herrenschmidt

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