Re: [PATCH -mm] sys_semctl gcc 4.1 warning fix

[Steven Rostedt <rostedt@goodmis.org>]

Oh fsck! gcc is hosed. I just tried out this BS module:

---
#include <linux/module.h>

int g = 0;

void func_int(int *y)
{
	*y = 0;
}

int warn_here(void)
{
	int x;

	printk("x=%d\n",x);

	return 0;
}

int but_not_here(void)
{
	int y;

	printk("y=%d\n",y);
	if (g) {
		func_int(&y);
	}
	return 0;
}

static int __init blah_init(void)
{
	warn_here();
	but_not_here();
        return 0;
}

static void __exit blah_exit(void)
{
	printk(KERN_INFO "Bye bye!\n");
}

module_init(blah_init);
module_exit(blah_exit);

MODULE_AUTHOR("My name here");
MODULE_DESCRIPTION("blah!");
MODULE_LICENSE("GPL");
---

And this is what I got!

  CC [M]  /home/rostedt/c/modules/warning.o
/home/rostedt/c/modules/warning.c: In function 'warn_here':
/home/rostedt/c/modules/warning.c:14: warning: 'x' is used uninitialized in this function
  Building modules, stage 2.


Why the fsck isn't the func but_not_here not getting a warning for the
first use of printk??  If I remove the if statement it gives me the
warning.  Hell, that if statement isn't even entered (g = 0).

If you remove the warn_here function altogether, this module gets no
warnings!!!

OK, this really bothers me :(

btw, if you are wondering. I did load the module, and here's the output
from dmesg:

x=-124784640
y=-124784640

And I even tried it with removing warn me, compiled with no warnings and
then got this:

y=134514958

Huh!

-- Steve

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