From: Andrew Morton <akpm@linux-foundation.org>
To: Paul Mundt <lethal@linux-sh.org>
Cc: adrian@newgolddream.dyndns.info, lkmladrian@gmail.com,
linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org,
penberg@cs.helsinki.fi, dbaryshkov@gmail.com,
penguin-kernel@i-love.sakura.ne.jp, lg@denx.de,
hannes@cmpxchg.org
Subject: Re: [PATCH] dma: fix up broken comparison in dma_alloc_from_coherent
Date: Tue, 27 Jan 2009 13:48:31 -0800 [thread overview]
Message-ID: <20090127134831.3dd04182.akpm@linux-foundation.org> (raw)
In-Reply-To: <20090121081118.GA14537@linux-sh.org>
On Wed, 21 Jan 2009 17:11:19 +0900
Paul Mundt <lethal@linux-sh.org> wrote:
> @@ -118,31 +118,32 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size,
> mem = dev->dma_mem;
> if (!mem)
> return 0;
> - if (unlikely(size > mem->size))
> - return 0;
> +
> + *ret = NULL;
> +
> + if (unlikely(size > (mem->size << PAGE_SHIFT)))
> + goto err;
Looks a bit broken on 64-bit.
`size' is ssize_t (long).
`mem->size' is `int'.
The left shift can overflow and cause badnesses.
> + *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
> + *ret = mem->virt_base + (pageno << PAGE_SHIFT);
Ditto.
Maybe it's a can't-happen (why?), but...
next prev parent reply other threads:[~2009-01-27 21:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-20 21:48 [PATCH] dma: fix up broken comparison in dma_alloc_from_coherent Adrian McMenamin
2009-01-20 21:55 ` Adrian McMenamin
2009-01-21 3:39 ` Paul Mundt
2009-01-21 8:11 ` Paul Mundt
2009-01-21 8:29 ` Guennadi Liakhovetski
2009-01-21 8:30 ` Paul Mundt
2009-01-27 21:48 ` Andrew Morton [this message]
2009-01-27 22:54 ` Paul Mundt
2009-01-28 8:36 ` Guennadi Liakhovetski
2009-02-06 12:22 ` [PATCH] fix broken size test in bitmap_find_free_region() Guennadi Liakhovetski
2009-02-06 21:29 ` Andrew Morton
2009-02-06 22:30 ` Guennadi Liakhovetski
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