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:

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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.

It is important to add that this problem existed even before auxiliary
bus conversion.

Thanks