[Bug 316187] Re: kernel 2.6.24 "Soft lockup" under load on VMWare ESX 3.5

Colin King colin.king at ubuntu.com
Mon Jan 26 14:38:28 UTC 2009

It appears that this kind of soft lockup kernel message easily
reproduced with the following code on a 2.6.24-xxx hardy server kernel
inside vmware server:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sched.h>

void setsched(void)
        struct sched_param mysched;
        mysched.sched_priority = 99;

        if( sched_setscheduler( 0, SCHED_FIFO, &mysched ) == -1 ) {
                fprintf(stderr,"Cannot set sched()\n");

int main(void)

        for (;;) {
        return (0);

Basically we get the program to hog a CPU and the kernel reports that we
have a CPU hogging task with a soft lockup message.

I'm now investigating this for any fixes upstream.

kernel 2.6.24 "Soft lockup" under load on VMWare ESX 3.5
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