Re: [PATCH v4 3/6] iommu: add ARM short descriptor page table allocator.

From: Robin Murphy
Date: Fri Oct 09 2015 - 13:42:00 EST


On 09/10/15 16:57, Will Deacon wrote:
On Tue, Sep 22, 2015 at 03:12:47PM +0100, Yong Wu wrote:
I would like to show you a problem I met, The recursion here may
lead to stack overflow while we test FHD video decode.

From the log, I get the internal variable in the error case: the
"size" is 0x100000, the "iova" is 0xfea00000, but at that time the
"blk_size" is 0x1000 as it was the map of small-page. so it enter the
recursion here.

After check the unmap flow, there is only a iommu_unmap in
__iommu_dma_unmap, and it won't check the physical address align in
iommu_unmap.

That sounds like a bug in __iommu_dma_unmap. Robin?

Isn't it just cf27ec930be9 again wearing different trousers? All I do is call iommu_unmap with the same total size that was mapped originally.

Robin.

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