[RFC] Kprobes for book-e

[Sulibhavi, Madhvesh]

Kumar Gala wrote on Thursday, June 19, 2008 10:15 PM
> To: Sulibhavi, Madhvesh
> > No!!, this code cannot be removed. My tests fail
> > while doing the probe test for do_gettimeofday and __kmalloc.
> > I get Oops and Segfault. I think i had got similar results
> > in my initial port using 2.6.26.39. Here is the log...
> 
> What is that test.  Can you send it to me.  Its not clear to me why  
> this is an issue.

My test code is very simple and it is added at the
end of this mail. Brief steps include..

1. Build k-007.c and k-008.c as kernel modules
2. Insert the k-008.ko first 
3. Insert k-007.ko
4. Do any operation like "ls"
5. Ooops will be seen followed by Segv


-Madhvesh

=================================================================
//k-008.c test code

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kprobes.h>
#include <linux/kallsyms.h>
 
static struct kprobe k_008_kp1;
 
static void __exit k_008_exit_probe(void)
{
        unregister_kprobe(&k_008_kp1);
}
 
static int k_008_pre_handler(struct kprobe *k_008_kp1, struct pt_regs
*p)
{
        return 0;
}
 
static int __init k_008_init_probe(void)
{

        /* Registering a kprobe */
        k_008_kp1.pre_handler = (kprobe_pre_handler_t)
k_008_pre_handler;
 
        k_008_kp1.symbol_name = "do_gettimeofday";
 
        if( register_kprobe(&k_008_kp1) <0 ) {
                printk("k-008.c: register_kprobe is failed\n");
                return -1;
        }
 
        register_kprobe(&k_008_kp1);
 
        return 0;
}
 
module_init(k_008_init_probe);
module_exit(k_008_exit_probe);
 
MODULE_DESCRIPTION("Kprobes test module");
MODULE_LICENSE("GPL");

=================================================================
//k-007.c test code

static struct kprobe k_007_kp, k_007_kp1;
int k_007_kmalloc_count = 0;
int k_007_kfree_count = 0;
 
static int k_007_kmalloc_hndlr(struct kprobe *kpr, struct pt_regs *p)
{
        k_007_kmalloc_count++;
        return 0;
}
 
static int k_007_kfree_hndlr(struct kprobe *kpr, struct pt_regs *p)
{
        k_007_kfree_count++;
        return 0;
}
 
static int __init k_007_kmf_init(void)
{
        k_007_kp.pre_handler = k_007_kmalloc_hndlr;
        k_007_kp1.pre_handler = k_007_kfree_hndlr;
 
        k_007_kp.symbol_name = "__kmalloc";
        k_007_kp1.symbol_name = "kfree";
 
        if( (register_kprobe(&k_007_kp) <0) ||
(register_kprobe(&k_007_kp1) <0) ) {
                printk("k-007.c: register_kprobe is failed\n");
                return -1;
        }
 
        return 0;
}
 
static void __exit k_007_kmf_exit(void)
{
        printk("%%%%%%%%%%%%%%%%%%%%%%%%%\n\n");
        printk("kmalloc count is %d \n", k_007_kmalloc_count);
        printk("kfree count is %d \n", k_007_kfree_count);
        printk("\n\n\n%%%%%%%%%%%%%%%%%%%%%%\n");
        unregister_kprobe(&k_007_kp);
        unregister_kprobe(&k_007_kp1);
        printk(KERN_INFO "k-007 exiting...\n");
}
 
module_init(k_007_kmf_init);
module_exit(k_007_kmf_exit);
MODULE_LICENSE("GPL");
===================================================================







-------------------------------------------------------------------
This email is confidential and intended only for the use of the individual or entity named above and may contain information that is privileged. If you are not the intended recipient, you are notified that any dissemination, distribution or copying of this email is strictly prohibited. If you have received this email in error, please notify us immediately by return email or telephone and destroy the original message. - This mail is sent via Sony Asia Pacific Mail Gateway.
-------------------------------------------------------------------