Re: [PATCH 0/9] net: bridge: reduce multicast checks in fast path

On Tue, Sep 02, 2025 at 10:16:04PM +0200, Linus Lüssing wrote:

On the other hand, moving the spinlock out of / around
__br_multicast_stop() would lead to a sleeping-while-atomic bug
when calling timer_delete_sync() in there. And if I were to change
these to a timer_delete() I guess there is no way to do the sync
part after unlocking? There is no equivalent to something like the
flush_workqueue() / drain_workqueue() for workqueues, but for
simple timers instead, right?

I'm wondering if it would be sufficient to use timer_del() on
.ndo_stop->br_dev_stop()->br_multicast_stop().

And use timer_del_sync() only on
.ndo_uninit->br_dev_uninit()-> br_multicast_dev_del()->
br_multicast_ctx_deinit() and
br_vlan_put_master()->br_multicast_ctx_deinit().


So basically only sync / wait for timer callbacks to finish if
their context is about to be free'd, on bridge or VLAN destruction?