Re: [PATCH v9 4/8] serial: 8250_omap: quiesce DMA IRQ handling before shutdown

[sashiko-bot@kernel.org]

> disable_irq_nosync() masks the UART interrupt without waiting for a
> running handler. That handler can have observed up->dma and continue
> using it while shutdown releases the DMA channels and clears the pointer.
> Synchronizing the IRQ later in serial core does not protect those accesses.
> 
> Publish the DMA shutdown gate under the port lock before the final RX
> flush and interrupt masking. Have DMA IRQ handling check the same gate
> under the lock, so a queued interrupt cannot restart receive processing
> after the final flush.
> 
> Drain the UART IRQ outside the port lock before releasing DMA state.
> The lock excludes competing RX processing during the flush, while
> disable_irq() also waits for a handler that observed up->dma before
> acquiring the lock.
> 
> Fixes: fef4f600319e ("serial: 8250: omap: Fix life cycle issues for interrupt handlers")
> Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261102-submit-serial-8250-dma-cancel-v1-v9-0-9159caade148@gmail.com?part=4