Re: [PATCH net] net: stmmac: keep est_lock across PTP clock adjustment

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi,

On 11/2/26 18:37, Lorenzo Bianconi wrote:
> stmmac_adjust_time() disables EST, drops est_lock to step the PTP clock,
> and then reacquires the lock to reprogram EST using a base time computed
> from the new clock value.
> 
> That leaves a window where a concurrent tc_taprio_configure() can program
> EST enabled with a base time derived from the pre-step clock.  The gate
> schedule then runs across the PTP step with a stale base time until
> stmmac_adjust_time() reprograms it.
> 
> Keep est_lock held for the whole disable/step/reprogram sequence so no
> other EST user can program the block while the clock is being stepped.
> 
> This does not introduce a new lock ordering: __stmmac_setup_est() already
> takes ptp_lock through gettimex64() while holding est_lock, and
> stmmac_adjust_systime() uses readl_poll_timeout_atomic(), so it does not
> sleep under ptp_lock.
> 
> Fixes: 23d96de472f7 ("net: stmmac: re-apply taprio offload in __stmmac_open() and stmmac_resume()")
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

I couldn't really figure out why the lock was released in the first
place, LGTM :)

Do you plan on addressing the sashiko pre-existing stuff ? seems to be
rare conditions but still :( sorry you end up having to deal with these...

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Maxime