From d9b7679611d320db4f4436f0281a7797f2e06e15 Mon Sep 17 00:00:00 2001 From: Abinash Singh Date: Thu, 7 Aug 2025 03:21:33 +0530 Subject: [PATCH] serial: 8250_platform: Reduce stack usage in serial8250_probe_acpi() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The function serial8250_probe_acpi() in 8250_platform.c triggered a frame size warning: drivers/tty/serial/8250/8250_platform.c: In function ‘serial8250_probe_acpi’: drivers/tty/serial/8250/8250_platform.c:152:1: warning: the frame size of 1160 bytes is larger than 1024 bytes [-Wframe-larger-than=] 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 Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250806215134.4921-2-abinashsinghlalotra@gmail.com Signed-off-by: Greg Kroah-Hartman --- 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/8250/8250_platform.c index c0343bfb80647..9938aeb917d85 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 @@ -110,41 +111,44 @@ void __init serial8250_isa_init_ports(void) static int serial8250_probe_acpi(struct platform_device *pdev) { struct device *dev = &pdev->dev; - struct uart_8250_port uart = { }; struct resource *regs; int ret, line; + struct uart_8250_port *uart __free(kfree) = kzalloc(sizeof(*uart), GFP_KERNEL); + if (!uart) + return -ENOMEM; + regs = platform_get_mem_or_io(pdev, 0); if (!regs) return dev_err_probe(dev, -EINVAL, "no registers defined\n"); switch (resource_type(regs)) { case IORESOURCE_IO: - uart.port.iobase = regs->start; + uart->port.iobase = regs->start; break; case IORESOURCE_MEM: - uart.port.mapbase = regs->start; - uart.port.mapsize = resource_size(regs); - uart.port.flags = UPF_IOREMAP; + uart->port.mapbase = regs->start; + uart->port.mapsize = resource_size(regs); + uart->port.flags = UPF_IOREMAP; break; default: return -EINVAL; } /* default clock frequency */ - uart.port.uartclk = 1843200; - uart.port.type = PORT_16550A; - uart.port.dev = &pdev->dev; - uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF; + uart->port.uartclk = 1843200; + uart->port.type = PORT_16550A; + uart->port.dev = &pdev->dev; + uart->port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF; - ret = uart_read_and_validate_port_properties(&uart.port); + ret = uart_read_and_validate_port_properties(&uart->port); /* no interrupt -> fall back to polling */ if (ret == -ENXIO) ret = 0; if (ret) return ret; - line = serial8250_register_8250_port(&uart); + line = serial8250_register_8250_port(uart); if (line < 0) return line; -- 2.47.3