On Mon, Nov 21, 2022 at 02:49:25PM +0200, Ilpo Järvinen wrote:
commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream.
Returning true from handle_rx_dma() without flushing DMA first creates a data ordering hazard. If DMA Rx has handled any character at the point when RLSI occurs, the non-DMA path handles any pending characters jumping them ahead of those characters that are pending under DMA.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
Applied to 5.4.y only. Fails to apply to 4.9.y, 4.14.y, or 4.19.y :(