I came across the following on http://tldp.org/LDP/tlk/mm/memory.htmlIf the faulting virtual address is invalid this means that the process  has attempted to access a virtual address that it should not have.  Maybe the application has gone wrong in some way, for example writing  to random addresses in memory. In this case the operating system will  terminate it, protecting the other processes in the system from this  rogue process.Now, my doubt is related to this phrase faulting virtual address is invalid.What is exactly meant by this? How can a *virtual address be invalid*? After all, any 32 bit value (on a 32 bit machine) would correspond to some 'valid' address in the virtual address space. 
Memory Management: Faulting virtual addresses
linux;memory;virtual memory
any 32 bit value (on a 32 bit machine) would correspond to some 'valid' address in the virtual address spaceIncorrect. Page entries can point to physical memory that doesn't exist or is marked off-limits, or they can contain an invalid pattern.