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Subject[PATCH]: iommu fix potential overflow in alloc_iommu()
(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.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>

diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index faf3229..baecb47 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -91,7 +91,7 @@ static unsigned long alloc_iommu(struct device *dev, int size)

base_index = ALIGN(iommu_bus_base & dma_get_seg_boundary(dev),
PAGE_SIZE) >> PAGE_SHIFT;
- boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
+ boundary_size = ALIGN((unsigned long long)dma_get_seg_boundary(dev) + 1,
PAGE_SIZE) >> PAGE_SHIFT;

spin_lock_irqsave(&iommu_bitmap_lock, flags);

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