From: Thomas Monjalon <email@example.com> To: Matan Azrad <firstname.lastname@example.org>, Bernard Iremonger <email@example.com>, Ferruh Yigit <firstname.lastname@example.org> Cc: "email@example.com" <firstname.lastname@example.org>, Gaetan Rivet <email@example.com>, David Marchand <firstname.lastname@example.org>, Jeff Guo <email@example.com>, Qi Zhang <firstname.lastname@example.org> Subject: Re: [dpdk-dev] [dpdk-stable] [PATCH 2/2] app/testpmd: fix invalid port detaching Date: Thu, 13 Feb 2020 13:37:03 +0100 Message-ID: <1645032.4herOUoSWf@xps> (raw) In-Reply-To: <email@example.com> Hi, This discussion becomes confusing so I do a summary below. I think we can do several fixes in 20.02. 12/02/2020 14:49, Ferruh Yigit: > On 2/3/2020 5:10 PM, Matan Azrad wrote: [stripping long discussion in favor of a summary below] > > Even if the PMD clear the device pointer, the testpmd still may release wrong rte_device. > > Yes it may, although that is less likely to occur, it requires a new device hot > added between close() and detach of the other device. > > Would you be agree to say there are two problems: > > 1) When testpmd close a port, a new attached port can re-use it over writing > some fields, relying the data structures of the closed port is not safe. > > 2) PMD not cleaning ethdev->device pointer in the .remove() may cause issues in > double detach of a port. > > > For (1) I suggest fixing it in the attach path, don't re-use an eth_dev port id > unless it is completely freed, may need to add new state for it. Does it make sense? Yes we could add a CLOSED state which is set on ethdev close. When the rte_device is freed, the PMD could set attached ports as UNUSED. But given some ethdev ports can be open and closed dynamically, I am not sure it is a good solution to keep them in CLOSED state and ask PMD to remember them. An alternative workaround could be to allocate port_id by incrementing a saved biggest id. So the race condition would be very unlikely. The drawbacks are having big port_id numbers and changing the id allocation algorithm (which is not documented anyway). The proposals above for port_id allocation or states rework cannot be done in 20.02. Let's discuss and work on it in a separated thread. > For (2) PMDs want to get hotplug support needs to fix it. Yes PMDs should clear rte_eth_devices[port_id].device in .remove(). We must also protect from user calling detach on a closed port by adding a check in cmd_operate_detach_port_parsed(), before calling detach_port_device(). The hotplug rmv_port_callback() must be able to call detach after close. There are three possible fixes: - revert the port_id_is_invalid() check in detach_port_device() - call rte_dev_remove(rte_device) directly - call a new function with rte_device (detach_port_device() can use it) About the function detach_port_device() itself, yes this function is strange to say the least. It was a convenience for detaching a rte_device from a port_id. The cleanup of siblings with RTE_ETH_FOREACH_DEV_OF(sibling, dev), should probably be removed. I've added it as a temporary solution before all PMDs are properly fixed: rte_eth_devices[sibling].device = NULL; For info, there is a function detach_device() used by the command "device detach <identifier>"
next prev parent reply other threads:[~2020-02-13 12:37 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-12 8:47 [dpdk-dev] [PATCH 1/2] bus/pci: fix driver detach clear Matan Azrad 2019-11-12 8:47 ` [dpdk-dev] [PATCH 2/2] app/testpmd: fix invalid port detaching Matan Azrad 2019-11-12 11:20 ` Iremonger, Bernard 2019-11-20 22:52 ` [dpdk-dev] [dpdk-stable] " David Marchand 2020-01-23 13:19 ` [dpdk-dev] " Yigit, Ferruh 2020-01-23 14:05 ` Matan Azrad 2020-01-23 14:48 ` [dpdk-dev] [dpdk-stable] " Ferruh Yigit 2020-01-23 15:29 ` Matan Azrad 2020-01-23 18:14 ` Ferruh Yigit 2020-01-23 19:25 ` Matan Azrad 2020-01-24 16:28 ` Ferruh Yigit 2020-01-25 18:56 ` Matan Azrad 2020-02-03 15:58 ` Ferruh Yigit 2020-02-03 17:10 ` Matan Azrad 2020-02-12 13:49 ` Ferruh Yigit 2020-02-13 12:37 ` Thomas Monjalon [this message] 2020-02-13 13:36 ` Thomas Monjalon 2020-02-13 14:00 ` Ferruh Yigit 2019-11-19 22:40 ` [dpdk-dev] [dpdk-stable] [PATCH 1/2] bus/pci: fix driver detach clear Thomas Monjalon 2019-11-20 9:02 ` Matan Azrad 2019-11-20 9:47 ` [dpdk-dev] [PATCH v2] " Matan Azrad 2019-11-20 13:03 ` [dpdk-dev] [dpdk-stable] " David Marchand 2019-11-20 13:44 ` Matan Azrad 2019-11-20 13:51 ` Thomas Monjalon 2019-11-20 17:22 ` David Marchand 2019-11-20 22:52 ` David Marchand
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