Re: [PATCH net v3 2/2] net: ravb: serialize PTP clock teardown

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 06/08/2026 10:51, xuanqiang.luo@linux.dev wrote:
> From: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
> 
> ravb_get_ts_info() can run without RTNL while ravb_ptp_stop() unregisters
> the PHC. The PTP interrupt handler can race with the same teardown, so both
> paths may access the clock while it is being freed.
> 
> Protect the clock pointer with priv->lock, clear it before unregistering
> the PHC, and unregister the detached clock outside the lock.

I think adding spinlock here is a bit of overkill. For
ravb_get_ts_info() you can simply extend struct ravb_ptp to store clock
index on init and reset it to -1 on ptp stop.

For interrupt race I think ravb_ptp_stop() can be split into disable
interrupt function (like ravb_ptp_disable()) and actual clock free. In
this case ravb_ptp_disable() can be run before synchronize_irq() with
ptp_clock_unregister() afterwards in teardown callbacks, like it's
already done for ring allocations.