On 4/24/2023 8:52 PM, David Marchand wrote:

Hello Anatoly,

On Wed, Apr 5, 2023 at 4:17 PM Burakov, Anatoly
<anatoly.bura...@intel.com> wrote:
Could you please provide some steps to reproduce the hotplug issue
you're having? It would be great to have a test case for this patchset
to put it in context.

I am working on CDX bus
(http://patchwork.dpdk.org/project/dpdk/patch/20230124140746.594066-2-nipun.gu...@amd.com/)
 and trying out some cases for plug/unplug.

The test is as follows:
    # Run testpmd application
    ./dpdk-testpmd -c 0x3 -- -i --nb-cores=1

    # Bind to VFIO
    echo "vfio-cdx" >  /sys/bus/cdx/devices/cdx-00\:00/driver_override
    echo "cdx-00:00" > /sys/bus/cdx/drivers_probe

    # Plug a device
    testpmd> port attach cdx:cdx-00:00

    #quit testpmd
    testpmd> quit

This gave error at testpmd exit that memory cannot be freed. On
debugging I updated this code and seems it should be seen with any of
the device.

I see similar test case (without quit) mentioned
https://doc.dpdk.org/dts/test_plans/hotplug_test_plan.html, but the
difference is that it is with igb_uio and issue is being observed with
VFIO.

Please note the device/bus mentioned in the commands is not yet
upstreamed in DPDK, but patches would be sent out soon.

Thanks,
Nipun


Thanks, I can reproduce this issue with regular devices too (run testpmd
with no devices, bind a NIC to VFIO, attach it, then quit). You're
correct in that since the initial mapping was done with mapping large
contiguous zones (such as when mempools are created before attach), any
subsequent freeing of memory will cause these errors to happen.

I don't think this can be fixed by anything other than not doing the
contiguous mapping thing, so provisionally, I think this patch should be
accepted. I'll play around with it some more and get back to you :)

Can we conclude on this topic?
It is best we merge this kind of change the sooner possible for a release.

Hi Anatoly,
        Can you kindly update on this?

Thanks,
Nipun


Thanks.


--
David Marchand

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