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Wed, 06 Aug 2025 13:10:26 -0700 (PDT) From: Abinash Singh To: andriy.shevchenko@linux.intel.com Cc: abinashsinghlalotra@gmail.com, arnd@arndb.de, gregkh@linuxfoundation.org, jirislaby@kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, sunilvl@ventanamicro.com, u.kleine-koenig@baylibre.com Subject: [PATCH v2 1/2] serial: 8250_platform: Reduce stack usage in serial8250_probe_acpi() Date: Thu, 7 Aug 2025 01:40:46 +0530 Message-ID: <20250806201047.754240-2-abinashsinghlalotra@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250806201047.754240-1-abinashsinghlalotra@gmail.com> References: <20250806201047.754240-1-abinashsinghlalotra@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The function serial8250_probe_acpi() in 8250_platform.c triggered a frame size warning: drivers/tty/serial/8250/8250_platform.c: In function =E2=80=98serial8250_pr= obe_acpi=E2=80=99: drivers/tty/serial/8250/8250_platform.c:152:1: warning: the frame size of 1= 160 bytes is larger than 1024 bytes [-Wframe-larger-than=3D] This patch reduces the stack usage by dynamically allocating the `uart` structure using kzalloc(), rather than placing it on the stack. This eliminates the overflow warning and improves kernel robustness. Signed-off-by: Abinash Singh --- drivers/tty/serial/8250/8250_platform.c | 26 ++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/tty/serial/8250/8250_platform.c b/drivers/tty/serial/8= 250/8250_platform.c index c0343bfb8064..50cec2413aeb 100644 --- a/drivers/tty/serial/8250/8250_platform.c +++ b/drivers/tty/serial/8250/8250_platform.c @@ -10,6 +10,7 @@ */ #include #include +#include #include #include #include @@ -110,9 +111,12 @@ void __init serial8250_isa_init_ports(void) static int serial8250_probe_acpi(struct platform_device *pdev) { struct device *dev =3D &pdev->dev; - struct uart_8250_port uart =3D { }; struct resource *regs; int ret, line; + struct uart_8250_port *uart __free(kfree) =3D kzalloc(sizeof(*uart), GFP_= KERNEL); + + if (!uart) + return -ENOMEM; =20 regs =3D platform_get_mem_or_io(pdev, 0); if (!regs) @@ -120,31 +124,31 @@ static int serial8250_probe_acpi(struct platform_devi= ce *pdev) =20 switch (resource_type(regs)) { case IORESOURCE_IO: - uart.port.iobase =3D regs->start; + uart->port.iobase =3D regs->start; break; case IORESOURCE_MEM: - uart.port.mapbase =3D regs->start; - uart.port.mapsize =3D resource_size(regs); - uart.port.flags =3D UPF_IOREMAP; + uart->port.mapbase =3D regs->start; + uart->port.mapsize =3D resource_size(regs); + uart->port.flags =3D UPF_IOREMAP; break; default: return -EINVAL; } =20 /* default clock frequency */ - uart.port.uartclk =3D 1843200; - uart.port.type =3D PORT_16550A; - uart.port.dev =3D &pdev->dev; - uart.port.flags |=3D UPF_SKIP_TEST | UPF_BOOT_AUTOCONF; + uart->port.uartclk =3D 1843200; + uart->port.type =3D PORT_16550A; + uart->port.dev =3D &pdev->dev; + uart->port.flags |=3D UPF_SKIP_TEST | UPF_BOOT_AUTOCONF; =20 - ret =3D uart_read_and_validate_port_properties(&uart.port); + ret =3D uart_read_and_validate_port_properties(&uart->port); /* no interrupt -> fall back to polling */ if (ret =3D=3D -ENXIO) ret =3D 0; if (ret) return ret; =20 - line =3D serial8250_register_8250_port(&uart); + line =3D serial8250_register_8250_port(uart); if (line < 0) return line; =20 --=20 2.50.1