Re: [PATCH v13 7/8] serial: 8250: retire canceled RX DMA before reusing the receive buffer

[sashiko-bot@kernel.org]

> The generic RX timeout path pauses a transfer, copies its data and
> terminates it asynchronously. Clearing rx_running at that point lets a
> new receive reuse the buffer and cookie while the old callback has not
> yet run. Inspecting the new cookie cannot distinguish that callback from
> the completion of a new transfer.
> 
> Reserve the receive buffer until a worker has drained the canceled
> callbacks. Keep FIFO access separate from callback retirement: after a
> successful pause and termination, clear rx_running while rx_terminating
> prevents another descriptor from reusing the buffer. Deliver the paused
> data before allowing the interrupt handler to drain the FIFO through PIO.
> Normal retirement only releases ownership and leaves subsequent receive
> handling to the UART interrupt.
> 
> Preserve the normal completion-path LSR read and gate DMA resubmission on
> [ ... ]
> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine")
> Suggested-by: Raul E Rangel <rrangel@chromium.org>
> Link: https://lore.kernel.org/r/20261109162135.906262-1-rrangel@chromium.org/
> Reviewed-by: Raul E Rangel <rrangel@chromium.org>
> Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261113-submit-serial-8250-dma-cancel-v1-v13-0-b857f2617ece@gmail.com?part=7