lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 5 Oct 2022 08:18:29 +0000 From: "Lucero Palau, Alejandro" <alejandro.lucero-palau@....com> To: Jiri Pirko <jiri@...nulli.us>, "Lucero Palau, Alejandro" <alejandro.lucero-palau@....com> CC: "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "davem@...emloft.net" <davem@...emloft.net>, "kuba@...nel.org" <kuba@...nel.org>, "pabeni@...hat.com" <pabeni@...hat.com>, "edumazet@...gle.com" <edumazet@...gle.com>, "dmichail@...gible.com" <dmichail@...gible.com>, "jesse.brandeburg@...el.com" <jesse.brandeburg@...el.com>, "anthony.l.nguyen@...el.com" <anthony.l.nguyen@...el.com>, "snelson@...sando.io" <snelson@...sando.io>, "drivers@...sando.io" <drivers@...sando.io>, "f.fainelli@...il.com" <f.fainelli@...il.com>, "yangyingliang@...wei.com" <yangyingliang@...wei.com> Subject: Re: [patch net-next 0/3] devlink: fix order of port and netdev register in drivers On 10/5/22 09:49, Jiri Pirko wrote: > Tue, Oct 04, 2022 at 05:31:10PM CEST, alejandro.lucero-palau@....com wrote: >> Hi Jiri, > I don't understand why you send this as a reply to this patchset. I > don't see the relation to it. I thought there was a relationship with ordering being the issue. Apologies if this is not the right way for rising my concern. > >> I think we have another issue with devlink_unregister and related >> devlink_port_unregister. It is likely not an issue with current drivers >> because the devlink ports are managed by netdev register/unregister >> code, and with your patch that will be fine. >> >> But by definition, devlink does exist for those things not matching >> smoothly to netdevs, so it is expected devlink ports not related to >> existing netdevs at all. That is the case in a patch I'm working on for >> sfc ef100, where devlink ports are created at PF initialization, so >> related netdevs will not be there at that point, and they can not exist >> when the devlink ports are removed when the driver is removed. >> >> So the question in this case is, should the devlink ports unregister >> before or after their devlink unregisters? > Before. If devlink instance should be unregistered only after all other > related instances are gone. > > Also, the devlink ports come and go during the devlink lifetime. When > you add a VF, split a port for example. There are many other cases. > > >> Since the ports are in a list owned by the devlink struct, I think it >> seems logical to unregister the ports first, and that is what I did. It >> works but there exists a potential concurrency issue with devlink user > What concurrency issue are you talking about? > 1) devlink port function set ... 2) predoit inside devlink obtains devlink then the reference to devlink port. Code does a put on devlink but not on the devlink port. 3) driver is removed. devlink port is removed. devlink is not because the put. 4) devlink port reference is wrong. >> space operations. The devlink code takes care of race conditions involving the >> devlink struct with rcu plus get/put operations, but that is not the >> case for devlink ports. >> >> Interestingly, unregistering the devlink first, and doing so with the >> ports without touching/releasing the devlink struct would solve the >> problem, but not sure this is the right approach here. It does not seem > It is not. As I wrote above, the devlink ports come and go. > > >> clean, and it would require documenting the right unwinding order and >> to add a check for DEVLINK_REGISTERED in devlink_port_unregister. >> >> I think the right solution would be to add protection to devlink ports >> and likely other devlink objects with similar concurrency issues. >> >> >> Let me know what you think about it. >> >> >> >> On 9/26/22 13:09, Jiri Pirko wrote: >>> CAUTION: This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email. >>> >>> >>> From: Jiri Pirko <jiri@...dia.com> >>> >>> Some of the drivers use wrong order in registering devlink port and >>> netdev, registering netdev first. That was not intended as the devlink >>> port is some sort of parent for the netdev. Fix the ordering. >>> >>> Note that the follow-up patchset is going to make this ordering >>> mandatory. >>> >>> Jiri Pirko (3): >>> funeth: unregister devlink port after netdevice unregister >>> ice: reorder PF/representor devlink port register/unregister flows >>> ionic: change order of devlink port register and netdev register >>> >>> .../net/ethernet/fungible/funeth/funeth_main.c | 2 +- >>> drivers/net/ethernet/intel/ice/ice_lib.c | 6 +++--- >>> drivers/net/ethernet/intel/ice/ice_main.c | 12 ++++++------ >>> drivers/net/ethernet/intel/ice/ice_repr.c | 2 +- >>> .../net/ethernet/pensando/ionic/ionic_bus_pci.c | 16 ++++++++-------- >>> 5 files changed, 19 insertions(+), 19 deletions(-) >>> >>> -- >>> 2.37.1 >>>
Powered by blists - more mailing lists