Re: [PATCH bpf-next v3 1/5] selftests/bpf: xsk selftests framework

On Fri, 27 Nov 2020 at 04:19, Yonghong Song [off-list ref] wrote:

On 11/26/20 1:22 PM, Weqaar Janjua wrote:

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On Thu, 26 Nov 2020 at 09:01, Björn Töpel [off-list ref] wrote:

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On 2020-11-26 07:44, Yonghong Song wrote:

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[...]

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What other configures I am missing?

BTW, I cherry-picked the following pick from bpf tree in this experiment.
    commit e7f4a5919bf66e530e08ff352d9b78ed89574e6b (HEAD -> xsk)
    Author: Björn Töpel [off-list ref]
    Date:   Mon Nov 23 18:56:00 2020 +0100

        net, xsk: Avoid taking multiple skbuff references

Hmm, I'm getting an oops, unless I cherry-pick:

36ccdf85829a ("net, xsk: Avoid taking multiple skbuff references")

*AND*

537cf4e3cc2f ("xsk: Fix umem cleanup bug at socket destruct")

from bpf/master.

Same as Bjorn's findings ^^^, additionally applying the second patch
537cf4e3cc2f [PASS] all tests for me

PREREQUISITES: [ PASS ]
SKB NOPOLL: [ PASS ]
SKB POLL: [ PASS ]
DRV NOPOLL: [ PASS ]
DRV POLL: [ PASS ]
SKB SOCKET TEARDOWN: [ PASS ]
DRV SOCKET TEARDOWN: [ PASS ]
SKB BIDIRECTIONAL SOCKETS: [ PASS ]
DRV BIDIRECTIONAL SOCKETS: [ PASS ]

With the first patch alone, as soon as we enter DRV/Native NOPOLL mode
kernel panics, whereas in your case NOPOLL tests were falling with
packets being *lost* as per seqnum mismatch.

Can you please test this out with both patches and let us know?

I applied both the above patches in bpf-next as well as this patch set,
I still see failures. I am attaching my config file. Maybe you can take
a look at what is the issue.

Thanks for the config, can you please confirm the compiler version,
and resource limits i.e. stack size, memory, etc.?

Only NOPOLL tests are failing for you as I see it, do the same tests
fail every time?

I will need to spend some time debugging this to have a fix.

Thanks,
/Weqaar

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Can I just run test_xsk.sh at tools/testing/selftests/bpf/ directory?
This will be easier than the above for bpf developers. If it does not
work, I would like to recommend to make it work.

yes test_xsk.shis self contained, will update the instructions in there with v4.

That will be great. Thanks!

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Thanks,
/Weqaar

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Björn