Re: [PATCH net v2] napi: fix race inside napi_enable

On Mon, 18 Oct 2021 16:36:36 -0700 Dany Madden wrote:

quoted

The BUG_ON() is here to make sure that when napi_enable() is called the
napi instance was dormant, i.e. disabled. We have "STATE_SCHED" bit set
on disabled NAPIs because that bit means ownership. Whoever disabled
the NAPI owns it.

That BUG_ON() could have been taken outside of the loop, there's no
point re-checking on every try.

Are you seeing NAPI-related failures? We had at least 3 reports in the
last two weeks of strange failures which look like NAPI state getting
corrupted on net-next...  

We hit two napi related crashes while attempting mtu size change.

Is it reproducible or happens rarely and randomly?