On 5/9/05, Vincenzo Mallozzi <vinjunior@xxxxxxxx> wrote:
> Hi all,
> I've modified the do_page_fault function adding the
> line
>
> printk(KERN_DEBUG "line added to
> PAGE_FAULT!!!\n");
>
> on top of it, then I've compiled the file and I've
> rebooted my machine.
> Now, I want to do a page fault in order to obtain the
> string "line added to PAGE_FAULT!!!" in my
> /var/log/debug file.
> I've read that COW is handled by do_page_fault
> function, so I've compiled and executed a simple
> "fork" file (listed below) in which I do a fork and
> then modify a global and a local variable in order to
> obtain a COW.
> At this point, I expect the searched string as output
> but nothing seems matter.
> Where I fail?
> Can anyone help me?
>
> Vincenzo Mallozzi.
>
> #include <sys/types.h>
> #include <unistd.h>
>
> int glob = 6;
> char buf[] = "a write to stdout\n";
>
> int main (void)
> {
> int var;
> pid_t pid;
>
> var = 88;
> if (write(STDOUT_FILENO, buf, sizeof(buf)-1) !=
> sizeof(buf)-1)
> printf("write error");
>
> printf("before fork\n");
> if ((pid=fork())<0)
> printf("fork error");
> else if (pid=0){
> glob++;
> var++;
> }else{
> glob++;
> var++;
> sleep(2);
> }
> exit(0);
> }
>
> ___________________________________
>
Check the output of the dmesg command or check in the latest
/var/log/messages file you should find the expected result.
Also this log message will not be seen on the terminals in X.
To see it in X please follow instructions mentioned in
http://webs1152.im1.net/reader.pl?pgid=lkmpghello_world
Regards,
Ashwin
--
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