"can not fork user shell: Cannot allocate memory"

When i'm login into my server using putty it log in perfectly but when i try to use : su it asks for pass开发者_Go百科word. But after a while without login as super user it shows

can not fork user shell: Cannot allocate memory

How to overcome this situation ?

If your user has processes, kill them. If you can ssh as root (khm..) try that.

Do some investigation to know why does this happened (top/mem/...). Of course you need memory for this so best wishes...

If these fail you have to use the good old ctrl+alt+reset combination :)