What does CPU#0 stuck mean?

Question

I have a validator and as a use types I need to test if item is in a array. Great, I can get the value in the input but how do a pass an array?

      mylist = ['a','b']
      constructor(private fb: FormBuilder){

          this.myForm = this.fb.group({
              slug: ['',[Validators.required,this.validateSlug]],
              description: ['']
          })
      }


validateSlug(control: FormGroup) {
        var valid:any;

        //THIS IF control.value IN mylist
        console.log('dude',control.value);
        valid=true;
        return valid ? null : { validateSlug: true };
   }

I cant seem to get access to anything in the validateSlug.

 slug: ['',[Validators.required,this.validateSlug(this.items)]],

validateSlug(param1) =>  (control: FormGroup) {
        var valid:any;
        console.log(control.value);

        //let fx = this.items.filter(x => x === control.value)[0];

        valid=true;
        return valid ? null : { validateSlug: true };
   }

Solution

The Linux kernel has a process which monitors each CPU on the system.

There are special interrupt(s) in the kernel. This interrupt(s) function calls a soft-lockup counter, it will compare the current time stamp with the specific kernel CPU data structure time information. If it looks like the current time stamp is greater than the defined threshold (in seconds) later as compared to the stored time stamp, it is assumed that the monitoring process or watchdog thread(s) have not executed in a respectable amount of time.

Why or how can a CPU soft lock occur? How can a CPU get locked if the kernel is carefully scheduling CPU access? Basically any poorly written code that loops a lot or infinitely, would own a CPU and get some priority. It can be a programming problem or 3rd party software.

Locking issues in drivers. Even kernel bugs in important drivers or the scheduler. A scheduler could tell schedule a driver routine to run and if that driver has problems and doesn’t check on it, that driver routine could own or hog that CPU for a longtime. By definition as described above, the watchdog would catch this and issue a soft lockup alert.

Soft lockups mostly hang a CPU and possibly your system temporarily.

A kernel update may fix the problem. To update the kernel, just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command(s) below:

for 32-bit system:

wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11-saucy/linux-headers-3.11.0-031100-generic_3.11.0-031100.201309021735_i386.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11-saucy/linux-headers-3.11.0-031100_3.11.0-031100.201309021735_all.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11-saucy/linux-image-3.11.0-031100-generic_3.11.0-031100.201309021735_i386.deb

for 64-bit system:

wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11-saucy/linux-headers-3.11.0-031100-generic_3.11.0-031100.201309021735_amd64.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11-saucy/linux-headers-3.11.0-031100_3.11.0-031100.201309021735_all.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11-saucy/linux-image-3.11.0-031100-generic_3.11.0-031100.201309021735_amd64.deb

For both 32-bit & 64-bit, run below command to install them:

sudo dpkg -i linux-headers-3.11.0*.deb linux-image-3.11.0*.deb

Once installed, restart your computer!

If you have problem with this kernel, run below command to remove it:

sudo apt-get purge linux-image-3.11.0*

^{Sources:Linux Kernel & How to upgrade Kernel Version}

Comments

[K7AAY]

Have you made sure the LiveCD downloaded OK by comparing the MD5 checkum published at Ubuntu's website matches the MD5 checksum of the ISO once downloaded? help.ubuntu.com/community/HowToMD5SUM explains how. If that's OK, please check the ISO by starting the process to boot into it then pressing {Esc} repeatedly; the menu which follows has an item, "Check Disk for Defects" - run that to make sure it burned OK.

[Mitch]

Can you add the output of dmesg | grep soft, and uname -r to your question?

[K7AAY]

Yes, click on the edit link underneath the tags - it's OK if adding the stuff Mitch asked for makes the question long.

[nbm]

Great answer, but it's not possible to get to a Terminal if we can't load Ubuntu in the first place. Loading from a LiveCD causes the error at startup. It is not possible to open a terminal.

[Günter Zöchbauer]

Where to you get this error? What is the problem with the code you added to your question. What does "I cant seem to get access to anything in the validateSlug" mean? What is "anything"?