Re: [PATCH] serial: qcom-geni: Drop unsafe rx_buf realloc from setup_fifos()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Aug 24, 2026 at 04:15:14PM +0530, Praveen Talari wrote:
> The RX buffer is allocated once during probe using a fixed DMA_RX_BUF_SIZE
> and is DMA-mapped for the lifetime of the port. However, setup_fifos()
> attempts to reallocate rx_buf whenever the reported RX FIFO depth changes.
> Since the DMA mapping is not re-established after reallocation, the buffer
> pointer may change while the DMA engine continues using the stale DMA
> address. This can result in RX DMA targeting memory that no longer
> corresponds to the active buffer, leading to invalid DMA accesses and
> potential memory corruption.
> 
> The RX FIFO depth is unrelated to the size of rx_buf. The buffer is
> allocated independently using DMA_RX_BUF_SIZE and all RX DMA paths consume
> it at that fixed size. As such, resizing the buffer based on FIFO depth
> changes provides no functional benefit.
> 
> Signed-off-by: Praveen Talari <ptalari@qualcomm.com>
> ---
> Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>

Why is this signed-off-by twice, with different email addresses?

confused,

greg k-h