[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20250805195155.742004-1-abinashsinghlalotra@gmail.com>
Date: Wed, 6 Aug 2025 01:21:54 +0530
From: Abinash Singh <abinashsinghlalotra@...il.com>
To: gregkh@...uxfoundation.org
Cc: jirislaby@...nel.org,
andriy.shevchenko@...ux.intel.com,
sunilvl@...tanamicro.com,
arnd@...db.de,
u.kleine-koenig@...libre.com,
linux-kernel@...r.kernel.org,
linux-serial@...r.kernel.org,
abinashsinghlalotra@...il.com
Subject: [RFC PATCH 1/2] tty: serial/8250: Fix build warning in serial8250_probe_acpi()
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 kmalloc(), rather than placing it on
the stack. This eliminates the overflow warning and improves kernel
robustness.
Signed-off-by: Abinash Singh <abinashsinghlalotra@...il.com>
---
The stack usage was further confirmed by using -fstack-usage flag.
it was using 1200 bytes:
..............................
drivers/tty/serial/8250/8250_platform.c:110:12:serial8250_probe_acpi 1200 static
drivers/tty/serial/8250/8250_platform.c:351:20:serial8250_exit 16 static
......................................
After applying the patch it becomes :
.........
It doesn't show up in stack usage and warning is fixed.
.......
This function is used for probing . So dynamic allocation will not create
any issues.
Thank You
---
drivers/tty/serial/8250/8250_platform.c | 29 +++++++++++++++----------
1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_platform.c b/drivers/tty/serial/8250/8250_platform.c
index c0343bfb8064..f7f9c5036d39 100644
--- a/drivers/tty/serial/8250/8250_platform.c
+++ b/drivers/tty/serial/8250/8250_platform.c
@@ -15,7 +15,7 @@
#include <linux/moduleparam.h>
#include <linux/once.h>
#include <linux/platform_device.h>
-
+#include <linux/cleanup.h>
#include <linux/serial_8250.h>
#ifdef CONFIG_SPARC
@@ -110,41 +110,46 @@ 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 uart_8250_port *uart __free(kfree) = NULL;
struct resource *regs;
int ret, line;
+ uart = kmalloc(sizeof(*uart), GFP_KERNEL);
+ if (!uart)
+ return -ENOMEM;
+ memset(uart, 0, sizeof(*uart));
+
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;
--
2.50.1
Powered by blists - more mailing lists