Messages in this thread | | | Date | Sun, 14 Nov 2021 08:19:02 +0200 | From | Leon Romanovsky <> | Subject | Re: [PATCH net-next] devlink: Require devlink lock during device reload |
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On Fri, Nov 12, 2021 at 08:38:56AM +0100, Jiri Pirko wrote: > Thu, Nov 11, 2021 at 01:17:52PM CET, leon@kernel.org wrote: > >On Thu, Nov 11, 2021 at 01:05:11PM +0100, Jiri Pirko wrote: > >> Tue, Nov 09, 2021 at 07:24:27PM CET, jgg@nvidia.com wrote: > >> >On Tue, Nov 09, 2021 at 08:20:42AM -0800, Jakub Kicinski wrote: > >> >> On Tue, 9 Nov 2021 11:33:35 -0400 Jason Gunthorpe wrote: > >> >> > > > I once sketched out fixing this by removing the need to hold the > >> >> > > > per_net_rwsem just for list iteration, which in turn avoids holding it > >> >> > > > over the devlink reload paths. It seemed like a reasonable step toward > >> >> > > > finer grained locking. > >> >> > > > >> >> > > Seems to me the locking is just a symptom. > >> >> > > >> >> > My fear is this reload during net ns destruction is devlink uAPI now > >> >> > and, yes it may be only a symptom, but the root cause may be unfixable > >> >> > uAPI constraints. > >> >> > >> >> If I'm reading this right it locks up 100% of the time, what is a uAPI > >> >> for? DoS? ;) > >> >> > >> >> Hence my questions about the actual use cases. > >> > > >> >Removing namespace support from devlink would solve the crasher. I > >> >certainly didn't feel bold enough to suggest such a thing :) > >> > > >> >If no other devlink driver cares about this it is probably the best > >> >idea. > >> > >> Devlink namespace support is not generic, not related to any driver. > > > >What do you mean? > > > >devlink_pernet_pre_exit() calls to devlink reload, which means that only > >drivers that support reload care about it. The reload is driver thing. > > However, Jason was talking about "namespace support removal from > devlink"..
The code that sparkles deadlocks is in devlink_pernet_pre_exit() and this will be nice to remove. I just don't know if it is possible to do without ripping whole namespace support from devlink.
Thanks
> > > > > >Thanks > > > >> > >> > > >> >Jason
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