Re: [PATCH net v1] net: defer __dev_set_promiscuity() to avoid sleeping in atomic context

On Thu, 19 Feb 2026 16:30:42 -0800 Stanislav Fomichev wrote:

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But you have a point, per netdevices.rst ndo_set_rx_mode is synchronized via
netif_addr_lock and we are breaking that with this patch.. :-(
(so I don't think we need an instance lock if we keep netif_addr_lock?)

For this particular issue, maybe we can do something similar to net_todo_list?
Instead of changing the promisc for !FLT under right here right now, move it
to the rtnl_unlock? Not sure how important the ordering is..  

Not sure. Another alternative is to implement the long standing idea of
having an async / sleeping version of ndo_set_rx_mode() orchestrated
by the core. Because a lot of drivers need to sleep, anyway, so they
just schedule a work from that callback.

Then we can say old ndo_set_rx_mode is under netif_addr_lock.
ndo_set_rx_mode_async is under instance lock.  

That sounds like a better plan going forward, but gonna need a bunch of
work to redo the addr lock it seems? We can start with moving promisc into
rtnl_unlock to unblock that "bridge vlan_filtering 1" and I
can look into adding an instance lock for set_rx_mode.. LMK if you prefer
me to focus on the latter and don't waste time on the former. 

I'd jump directly to the latter.
Former adds its own trickiness and IIUC the latter will deprecate it.