Date: Wed, 25 May 2011 10:18:40 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Milton Miller <miltonm@bga.com>
cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] irq: radix_tree_insert can fail
In-Reply-To: <radix-insert-can-fail@mdm.bga.com>
Message-ID: <alpine.LFD.2.02.1105251017460.3078@ionos>
References: <generic-irq-changes@mdm.bga.com> <radix-insert-can-fail@mdm.bga.com>
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On Wed, 25 May 2011, Milton Miller wrote:

> Check the insert, and if it fails cleanup and free all partial work.
> 
> Sparse irq was not checking the return code from radix_tree_insert,
> but it may need to allocate memory and can fail.  If it failed,
> it still claimed success to the caller but the affected irq(s) are
> unavailable and the reference to the affected descriptors is leaked.
> 
> Signed-off-by: Milton Miller <miltonm@bga.com>
> ---
> I started by tring to change free_desc to take the descriptor pointer
> and pushing that down, but that soon ran into conflicts between the
> array and sparse implementations, and/or the old dynamic irq cleanup
> function that is still used by some architectures.  This version is
> targeted, and also protects against scribbles to irq_data.irq.

The simpler solution is to move irq_insert_desc() into alloc_desc()
and deal with the error case there.

Thanks,

	tglx
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