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From: Ami Sabo <AmiS@Radware.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
CC: "dev@dpdk.org" <dev@dpdk.org>, "stable@dpdk.org" <stable@dpdk.org>
Thread-Topic: [PATCH 2/2] net/virtio-user: fix multi-process issue
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Date: Tue, 28 Feb 2017 07:50:47 +0000
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Subject: Re: [dpdk-stable] [PATCH 2/2] net/virtio-user: fix multi-process
issue
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Hi,
You are right, the commit I mentioned didn't cause the issue - it just floo=
ded it.
The real issue is that rte_eth_dev_allocate should be called only from the =
primary process.
Tomas's commit flood the issue by resseting rte_eth_dev_data, so now, when =
the virtio-user secondary process comes up and calls rte_eth_dev_allocate
It clears the ethdev->data struct (so fields like rx_queues, mac_addrs, etc=
will be 0, plus this may cause race condition between the primary and seco=
ndary processes...)=20
--ami
-----Original Message-----
From: Yuanhan Liu [mailto:yuanhan.liu@linux.intel.com]=20
Sent: Tuesday, February 28, 2017 8:40 AM
To: Ami Sabo
Cc: dev@dpdk.org; stable@dpdk.org
Subject: Re: [PATCH 2/2] net/virtio-user: fix multi-process issue
On Sun, Feb 26, 2017 at 11:55:26AM +0200, Ami Sabo wrote:
> Secondary process doesn't properly attach to the rte_eth_device=20
> initialized by the primary process.
>=20
> ccessing device from secondary process (e.g. via rte_eth_rx_burst),=20
> causes process to crash. because rte_eth_dev_data is not properly set.
>=20
> The issue was flood by
> 'commit 7f95f78a8aea ("ethdev: clear data when allocating device")'
> which now clears rte_eth_dev_data entry.
> For pci devices the struct is initialized by rte_eth_dev_pci_probe
> ->eth_dev_attach_secondary().
> However, for virtio-user virtio_user_pmd_probe() is called instead of=20
> rte_eth_dev_pci_probe().
>=20
> The fix is to call rte_eth_dev_attach_secondary(), for secondary=20
> process, from virtio_user_pmd_probe.
>=20
> Fixes: 7f95f78a8aea ("ethdev: clear data when allocating device")
Are you sure that's the real culprit? As I'm aware of, virtio-user is not b=
uilt with multiple process support in the beginning. That said, it's likely=
that the first commit introduces virtio-user is the "culprit" commit.
Besides that, the code looks good to me. If Thomas is fine with your first =
patch, I could merge them to my tree.
--yliu