Can mm_struct of a process be null?

Chetan Nanda chetannanda at gmail.com
Sun Nov 17 22:42:29 EST 2013


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 <pauldaviesc at gmail.com>wrote:

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