kernel zeroing of user space memory?

["Ryan MacArthur" <ryan.macarthur@xxxxxxxxx>]

Hi,

I am trying to understand the process by which pages of memory get de/re-allocated.

Lets say I have a process that exits, will the kernel memory management system zero out (entirely) the pages that my process was using, or will it just re-assign them with the old data still present.

I found this gfp mask:

#define __GFP_ZERO      0x8000u /* Return zeroed page on success */

So it seems that a calling process would have to specifically _ask_ for a zeroed out page, otherwise it would get a page with old application data in it (passwords,keys?)

Any insight would be greatly appreciated.

-ryan