lkml.org 
[lkml]   [2003]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] O(1) proc_pid_readdir
William Lee Irwin III wrote:

>The NMI oopses are mostly decoded by hand b/c in-kernel (and other)
>backtrace decoders can't do it automatically. I might have to generate
>some fresh data, with some kind of hack (e.g. hand-coded NMI-based kind
>of smp_call_function) to trace the culprit and not just the victim.
>The victims were usually stuck in fork() or exit().
>
Could you check if the attached test app triggers the NMI oopser?

--
Manfred
/*
* numados: stress test the tasklist lock.
*
* Copyright (C) 1999, 2001, 2003 by Manfred Spraul.
* All rights reserved except the rights granted by the GPL.
*
* Redistribution of this file is permitted under the terms of the GNU
* General Public License (GPL) version 2 or later.
* $Header: /pub/home/manfred/cvs-tree/getdents/getdents.cpp,v 1.1 2003/03/16 21:07:43 manfred Exp $
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/types.h>
#include <linux/dirent.h>
#include <linux/unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

#define BUFSZ 4096
unsigned char entries[BUFSZ];

#define _syscall3(type,name,type1,arg1,type2,arg2,type3,arg3) \
type name(type1 arg1,type2 arg2,type3 arg3) \
{ \
long __res; \
__asm__ volatile ("int $0x80" \
: "=a" (__res) \
: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
"d" ((long)(arg3))); \
__syscall_return(type,__res); \
}
_syscall3(int, getdents, uint, fd, struct dirent *, dirp, uint, count);

static void poll_tasklist(void)
{
int fd, retval;
for (;;) {
fd = open("/proc",O_RDONLY);
if (fd < 0) {
printf("open failed, errno %d.\n", errno);
exit(4);
}
lseek(fd, 1000000, SEEK_SET);
retval = getdents(fd, (struct dirent *)entries, BUFSZ);
close(fd);
}
}
int main(int argc, char **argv)
{
int retval;
int forks, readers;
int i;
printf("numados <forks> <readers>\n");
if (argc != 3)
return 1;
forks=atoi(argv[1]);
readers=atoi(argv[2]);
printf("Forks: %d.\n", forks);
for (i=0;i<forks;i++) {
retval = fork();
if (retval < 0) {
printf("fork failed for process %d, errno %d.\n", i+1, errno);
return 2;
} else if (retval == 0) {
for (;;) sleep(1000);
} else {
printf(" child %d: pid %d created\n", i, retval);
fflush(stdout);
}
}
printf("%d child processes created.\n", i);
for (i=0;i<readers;i++) {
retval = fork();
if (retval < 0) {
printf("fork failed for process %d, errno %d.\n", i+1, errno);
return 3;
} else if (retval == 0) {
poll_tasklist();
for (;;) sleep(10000);
}
}
printf("%d reader processes created.\n", i);
for(;;) sleep(1000);
}
\
 
 \ /
  Last update: 2005-03-22 13:34    [W:0.122 / U:0.112 seconds]
©2003-2011 Jasper Spaans. Advertise on this site