On Tue, Nov 25, 2003 at 06:01:59PM +0100, Obermeier Markus ICM MP PD TS wrote:
|Hi,
|
|I have developped a small kernel module. It schedules a regular timer calling the timeout function.
|In this timeout function I would like to open the file /proc/net/dev from proc-filesystem.
you shouldn't!!!!
|If I do,
|the kernel crashes.
Because you shouldn't issue a sys_* from kernel_space!!!!!
(sometimes you can [by changin segment limitis{if interested looks at
the khttpd source}] but is not your case)
|How do I make system calls in timer callback function.
Please Avoid!
|static void hello_timeout(unsigned long ptr) {
| printk(KERN_ALERT "Timeout %u\n",num);
| if (last_call) del_timer(&list);
| else {
| num++;
| init_timer(&list);
| list.function = hello_timeout;
| list.data = 0;
| list.expires = jiffies + HZ;
| add_timer(&list);
| if ((fd=sys_open("/proc/net/dev",O_RDONLY, 0x444)) == 0) {
^
|
+-----+
|
|
+-------- here is a source of pain ;)
if you want to read those infos from kernel space look at the
dev_get_info function (located in net/core/dev.c)
Have fun!!
--
Daniele.
"I could have made money this way, and perhaps amused myself writing code.
But I knew that at the end of my career, I would look back on years of
building walls to divide people, and feel I had spent my life making the
world a worse place."
Richard Stallman
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