Message-ID: <sashiko-outbox-204391@kernel.org>
From: sashiko-bot@kernel.org
Subject: Re: [PATCH v10 2/8] serial: serialize asynchronous write wakeups
 with the port lock
Reply-To: sashiko-reviews@lists.linux.dev
To: "James Hilliard" <james.hilliard1@gmail.com>
Cc: linux-serial@vger.kernel.org
In-Reply-To: <20261108-submit-serial-8250-dma-cancel-v1-v10-2-e6227ddb95b1@gmail.com>
References: <20261108-submit-serial-8250-dma-cancel-v1-v10-0-e6227ddb95b1@gmail.com>
 <20261108-submit-serial-8250-dma-cancel-v1-v10-2-e6227ddb95b1@gmail.com>
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Date: Mon, 09 Nov 2026 04:04:53 +0000
Precedence: list

> uart_write_wakeup() expects the UART port lock to be held. Several worker,
> DMA completion and interrupt paths call it without that lock, including
> indirect calls from uart_handle_cts_change() and the transmit helpers.
>=20
> Take the port lock around these notifications or their transmit helper.
> Keep sleeping SPI and regmap accesses outside the locked region, and keep
> the FSL LPUART completion lock held through its wakeup. Acquire the port
> lock after releasing private channel locks to preserve the ordering used
> by UART callbacks. In the MUX timer, publish available FIFO space under
> the port lock and keep the hardware FIFO-drain wait outside it.
>=20
> Use plain port locking in hard-IRQ handlers and in helpers whose callers
> already mask interrupts. Atmel status handling is also called during
> resume, where lock_suspended is acquired with interrupts disabled; JSM
> interrupt processing holds its IRQ-saving board lock. Keep IRQ-saving
> [ ... ]
> the restart worker during shutdown and removal. Release Lantiq's hardware
> lock through the transmit helper's completion hook before notifying the
> line discipline.
>=20
> Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

Sashiko has reviewed this patch and found no issues.

--=20
Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261108-submit-ser=
ial-8250-dma-cancel-v1-v10-0-e6227ddb95b1@gmail.com?part=3D2