On Tue, Oct 27, 2020 at 12:52:30PM +0000, Parav Pandit wrote:

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From: hch@lst.de hch@lst.de Sent: Tuesday, October 27, 2020 1:41 PM

On Mon, Oct 26, 2020 at 05:23:48AM +0000, Parav Pandit wrote:

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Hi Christoph,

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From: Jakub Kicinski kuba@kernel.org Sent: Saturday, October 24, 2020 11:45 PM

CC: rdma, looks like rdma from the stack trace

On Fri, 23 Oct 2020 20:07:17 -0700 syzbot wrote:

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syzbot has found a reproducer for the following issue on:

HEAD commit: 3cb12d27 Merge tag 'net-5.10-rc1' of

git://git.kernel.org/..

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In [1] you mentioned that dma_mask should not be set for dma_virt_ops. So patch [2] removed it.

But check to validate the dma mask for all dma_ops was added in [3].

What is the right way? Did I misunderstood your comment about

dma_mask in [1]?

No, I did not say we don't need the mask. I said copying over the various dma-related fields from the parent is bogus.

I think rxe (and ther other drivers/infiniband/sw drivers) need a simple dma_coerce_mask_and_coherent and nothing else.

I see. Does below fix make sense? Is DMA_MASK_NONE correct?

DMA_MASK_NONE is gone in 5.10. I think you want DMA_BIT_MASK(64). That isn't actually correct for 32-bit platforms, but good enough.