Re: [PATCH v4] tty: serial: max3100: shut down timer before freeing port

[sashiko-bot@kernel.org]

> max3100_shutdown() stops the polling timer but returns early during
> system suspend. If the SPI device is unbound before resume, the serial
> core does not call max3100_shutdown() again, so max3100_remove() frees
> the port while the timer remains armed. max3100_timeout() may then
> access the freed port and re-arm the timer.
> 
> Add final timer teardown to max3100_remove() and use
> timer_shutdown_sync() to prevent a racing callback from re-arming it.
> Also free the IRQ and destroy the workqueue there before freeing the
> port. Keep timer_delete_sync() in max3100_shutdown() so that a
> subsequent open() can re-arm the timer.
> 
> The workqueue is created before request_irq() and destroyed on both
> request_irq() failure and normal shutdown. Its presence at remove thus
> identifies the IRQ left registered when suspend bypasses shutdown.
> [ ... ]
> 
> Fixes: 7831d56b0a35 ("tty: MAX3100")
> Cc: stable@vger.kernel.org # 6.2+
> Assisted-by: Codex:gpt-5.6
> Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>

Sashiko has reviewed this patch and found no issues. It looks great!

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