From 79b8ddbebf7420fa71c76d4f5f892b21ef1e4456 Mon Sep 17 00:00:00 2001 From: Bjorn Andersson Date: Thu, 2 Jun 2016 17:48:28 -0700 Subject: [PATCH] tty: serial: msm: Don't read off end of tx fifo commit 30acf549ca1e81859a67590ab9ecfce3d1050a0b upstream. For dm uarts in pio mode tx data is transferred to the fifo register 4 bytes at a time, but care is not taken when these 4 bytes spans the end of the xmit buffer so the loop might read up to 3 bytes past the buffer and then skip the actual data at the beginning of the buffer. Fix this by, analogous to the DMA case, make sure the chunk doesn't wrap the xmit buffer. Fixes: 3a878c430fd6 ("tty: serial: msm: Add TX DMA support") Cc: Ivan Ivanov Reported-by: Frank Rowand Reported-by: Nicolas Dechesne Signed-off-by: Bjorn Andersson Acked-by: Andy Gross Tested-by: Frank Rowand Reviewed-by: Stephen Boyd Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/msm_serial.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index dcde955475dc..e1de4944e0ce 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -726,7 +726,7 @@ static void msm_handle_tx(struct uart_port *port) return; } - pio_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE); + pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); dma_min = 1; /* Always DMA */ -- 2.11.0