Re: [PATCH]: iommu fix potential overflow in alloc_iommu()

From: Prarit Bhargava
Date: Mon Jul 21 2008 - 11:48:23 EST

FUJITA Tomonori wrote:
On Mon, 21 Jul 2008 11:21:39 -0400
Prarit Bhargava <prarit@xxxxxxxxxx> wrote:

FUJITA Tomonori wrote:
On Mon, 21 Jul 2008 10:15:22 -0400
Prarit Bhargava <prarit@xxxxxxxxxx> wrote:

(This didn't appear on LKML or any of the mirrors ... trying again)

It is possible that alloc_iommu()'s boundary_size overflows as
dma_get_seg_boundary can return 0xffffffff. In that case, further usage of
boundary_size triggers a BUG_ON() in the iommu code.
Did you actually hit this? pci-gart_64.c is used only by X86_64.
I hit this by declaring a device struct and not declaring a value for dev->dma_parms->segment_boundary_mask.

What do you mean? You set dev->dma_params but does't set
dev->dma_parms->segment_boundary_mask? If so, you need to fix your
code. If you set dev->dma_parms, dma_parms needs to be initialized

No, I didn't set dev->dma_params.


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