From: Thomas Monjalon <firstname.lastname@example.org> To: Matan Azrad <email@example.com>, Bernard Iremonger <firstname.lastname@example.org>, Ferruh Yigit <email@example.com> Cc: 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 14:36:41 +0100 Message-ID: <3042500.kGzlxMrEDr@xps> (raw) In-Reply-To: <1645032.4herOUoSWf@xps> More details below about the plan for 20.02. 13/02/2020 13:37, Thomas Monjalon: > 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(). I am sending a patch adding memset(eth_dev, 0, sizeof(struct rte_eth_dev)); in rte_eth_dev_release_port(). But this patch cannot be merged after 20.02-rc1. It will wait for 20.05. > 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(). I am sending a patch adding RTE_ETH_VALID_PORTID_OR_RET() in cmd_operate_detach_port_parsed(). It should fix the issue observed by Matan with double detach. It will be a double protection if keeping the check port_id_is_invalid() in 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) I am sending a patch implementing the third alternative as it is both keeping the detach behaviour and fixing the race condition (i.e. protect from new port re-using the port_id between close and detach). > 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; I propose sending such patch in 20.05 in order to merge the memset above first, and have time to get agreement from all PMD maintainers. > For info, there is a function detach_device() used by the command > "device detach <identifier>"
next prev parent reply index 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 2020-02-13 13:36 ` Thomas Monjalon [this message] 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
Reply instructions: You may reply publically to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=3042500.kGzlxMrEDr@xps \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
DPDK patches and discussions Archives are clonable: git clone --mirror http://inbox.dpdk.org/dev/0 dev/git/0.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 dev dev/ http://inbox.dpdk.org/dev \ firstname.lastname@example.org public-inbox-index dev Newsgroup available over NNTP: nntp://inbox.dpdk.org/inbox.dpdk.dev AGPL code for this site: git clone https://public-inbox.org/ public-inbox