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Mon, 20 Apr 2026 07:04:29 -0700 (PDT) From: Biju X-Google-Original-From: Biju To: Greg Kroah-Hartman , Jiri Slaby Cc: Biju Das , Geert Uytterhoeven , Lad Prabhakar , Thierry Bultel , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Biju Das , linux-renesas-soc@vger.kernel.org Subject: [PATCH v3 1/3] serial: sh-sci: Avoid divide-by-zero fault Date: Mon, 20 Apr 2026 15:04:21 +0100 Message-ID: <20260420140426.237865-2-biju.das.jz@bp.renesas.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260420140426.237865-1-biju.das.jz@bp.renesas.com> References: <20260420140426.237865-1-biju.das.jz@bp.renesas.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Biju Das The expression (10000 * bits) / (baud / 100) can produce a divide-by-zero if baud is less than 100, since integer division yields zero before the outer divide occurs. Rewrite it as (10000 * bits) * 100 / baud, which is algebraically equivalent but eliminates the intermediate division, making a zero divisor impossible for any valid baud rate. Signed-off-by: Biju Das --- v3: * New patch. --- drivers/tty/serial/sh-sci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 6c819b6b2425..7473b26ce9cf 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -2915,7 +2915,7 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, } /* Calculate delay for 2 DMA buffers (4 FIFO). */ - s->rx_frame = (10000 * bits) / (baud / 100); + s->rx_frame = (10000 * bits) * 100 / baud; #ifdef CONFIG_SERIAL_SH_SCI_DMA s->rx_timeout = s->buf_len_rx * 2 * s->rx_frame; #endif -- 2.43.0