Can mm_struct of a process be null?

Yes, current->mm points to user space context for the current process.
Now for a kernel threads there is no user space context and for them
current->mm would be NULL.

Thanks,
Chetan Nanda


On Fri, Nov 15, 2013 at 9:54 PM, Paul Davies C [off-list ref]wrote:

 Hi,
    I happen to find this code snippet in the kernel source :









*struct mm_struct *mm=current->mm;     /* some other code */     if(mm){
/*<==Why is this here? */         /*read the contents by locking*/     } *
The* if  *checks whether the mm_struct of the current process is NULL or
not. That means the mm_struct of a process can become NULL. How can that
happen?

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