Re: [PATCH v6 5/5] leds: trigger: netdev: Serialize mode/interval stores with trigger lock

[sashiko-bot@kernel.org]

> From: Alexander Sverdlin <alexander.sverdlin@siemens.com>
> 
> netdev_led_attr_store() and interval_store() update ->mode and run
> set_baseline_state() without trigger_data->lock. kernfs only serializes
> writes to the same file, so two attribute writes race on the non-atomic
> read-modify-write of ->mode:
> 
>   CPU0 (echo 1 > link_10)       CPU1 (echo 1 > link_100)
>   -----------------------       ------------------------
>   mode = trigger_data->mode;
>                                 mode = trigger_data->mode;
>   set_bit(LINK_10, &mode);
>                                 set_bit(LINK_100, &mode);
>   trigger_data->mode = mode;
>                                 trigger_data->mode = mode;  // LINK_10 lost
> [ ... ]
> 
> Cc: stable@vger.kernel.org
> Closes: https://lore.kernel.org/all/sashiko-outbox-178980@kernel.org/
> Fixes: d5e01266e7f5 ("leds: trigger: netdev: add additional specific link speed mode")
> Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>

Sashiko has reviewed this patch and found no issues.

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