Need some pointers to debug a KASAN splat in NVMe over Fabrics with rdma-rxe

[Johannes Thumshirn]

Hi Moni,

On 03/08/2017 05:33 PM, Moni Shoua wrote:
> Your report and analysis seem to be accurate (regarding value of wqe->iova)
> Unfortunately we didn't have a chance yet to run kernel application
> tests but I will try to add them soon and be able to debug it myself.
> In the meantime

OK, thanks. This is highly appreciated as I think Soft RoCE is the
coolest thing since sliced bread for quick NVMf/iSER and SRP tests.

> 1. DId the test fail completely or is it just the KASAN error that
> made you look at init_send_wqe()?

No it fails completely. I can see both hosts talk RDMA/NVMf to each
other but the initiator side can't establish a connection. Without KASAN
I couldn't find a reason for it other than the following log message:
rdma_rxe: qp#17 moved to error state

I must admit I haven't looked up it's source yet, as my first test had
KASAN enabled.

> 2. You can take a look at librxe implementation of init_send_wqe() (it
> looks slightly different from kernel's implementation) and see what
> happens if you change implementation accordingly.

OK I'll have a look and hopefully come back with a (RFC) patch (fingers
crossed).

Thanks,
	Johannes
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Johannes Thumshirn                                          Storage
jthumshirn at suse.de                                +49 911 74053 689
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