Re: [BUG][2.6.13.4] Memoryleak - idr_layer_cache slab - inotify?

[Stefan Jones <stefan.jones@churchillrandoms.co.uk>]

Stefan Jones wrote:

> I noticed this a while back when gam_server (new fam replacement)
> started playing up and the idr_layer_cache slab used up 300Mb of RAM.
>
> To reproduce:
>
> Run gnome and make sure it is using gam_server for fam.
>
> In one console do:
>
> while true ;do sleep 0.1 ; killall -w gam_server; done
>
> In another try slabtop and see the idr_layer_cache slab climb, eating
> memory (abit slowly).
> ( Gnome restarts gam_server after each kill for you and gets it doing
> stuff )
>
> I looked though the source and inotify does use the idr_layer_cache slab
> and gam_server also uses inotify.

Made a standalone testcase, run this and the kernel will eat up your 
memory (seen via slabtop):

( this should compile everywhere )

#include <sys/wait.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/select.h>
#include <asm/unistd.h>
#include <errno.h>


#define __NR_inotify_init    291
#define __NR_inotify_add_watch    292
#define __NR_inotify_rm_watch    293


_syscall0(int, inotify_init);
_syscall3(int, inotify_add_watch, int, fd, const char *, name, unsigned 
int, mask);
_syscall2(int, inotify_rm_watch, int, fd, unsigned int, wd);

int main() {
    pid_t pid;
    int fd;
    int wd;
    const char *dirname=".";
    unsigned int mask = 0xffffffff;
    int stat;
   
    for(;;) {
        if(!(pid = fork())) {
            fd = inotify_init ();

            wd = inotify_add_watch (fd, dirname, mask);
            if (wd < 0)
                perror ("inotify_add_watch");

            kill(getpid(),SIGTERM);
        }
        waitpid(pid,&stat,0);
    }
   
    return 0;
}