e8ac6ea8a4
In commit e80d666 "flagday: kill pt_regs argument of do_fork()", the
arguments to do_fork() changed.
The example code in jprobe_example.c was not updated to match, so the
arguments inside the jprobe handler do not match reality.
Fix it by updating the arguments to match do_fork(). While we're at it
use pr_info() for brevity, and print stack_start as well for interest.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
67 lines
1.7 KiB
C
67 lines
1.7 KiB
C
/*
|
|
* Here's a sample kernel module showing the use of jprobes to dump
|
|
* the arguments of do_fork().
|
|
*
|
|
* For more information on theory of operation of jprobes, see
|
|
* Documentation/kprobes.txt
|
|
*
|
|
* Build and insert the kernel module as done in the kprobe example.
|
|
* You will see the trace data in /var/log/messages and on the
|
|
* console whenever do_fork() is invoked to create a new process.
|
|
* (Some messages may be suppressed if syslogd is configured to
|
|
* eliminate duplicate messages.)
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kprobes.h>
|
|
|
|
/*
|
|
* Jumper probe for do_fork.
|
|
* Mirror principle enables access to arguments of the probed routine
|
|
* from the probe handler.
|
|
*/
|
|
|
|
/* Proxy routine having the same arguments as actual do_fork() routine */
|
|
static long jdo_fork(unsigned long clone_flags, unsigned long stack_start,
|
|
unsigned long stack_size, int __user *parent_tidptr,
|
|
int __user *child_tidptr)
|
|
{
|
|
pr_info("jprobe: clone_flags = 0x%lx, stack_start = 0x%lx "
|
|
"stack_size = 0x%lx\n", clone_flags, stack_start, stack_size);
|
|
|
|
/* Always end with a call to jprobe_return(). */
|
|
jprobe_return();
|
|
return 0;
|
|
}
|
|
|
|
static struct jprobe my_jprobe = {
|
|
.entry = jdo_fork,
|
|
.kp = {
|
|
.symbol_name = "do_fork",
|
|
},
|
|
};
|
|
|
|
static int __init jprobe_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = register_jprobe(&my_jprobe);
|
|
if (ret < 0) {
|
|
printk(KERN_INFO "register_jprobe failed, returned %d\n", ret);
|
|
return -1;
|
|
}
|
|
printk(KERN_INFO "Planted jprobe at %p, handler addr %p\n",
|
|
my_jprobe.kp.addr, my_jprobe.entry);
|
|
return 0;
|
|
}
|
|
|
|
static void __exit jprobe_exit(void)
|
|
{
|
|
unregister_jprobe(&my_jprobe);
|
|
printk(KERN_INFO "jprobe at %p unregistered\n", my_jprobe.kp.addr);
|
|
}
|
|
|
|
module_init(jprobe_init)
|
|
module_exit(jprobe_exit)
|
|
MODULE_LICENSE("GPL");
|