Hi Colin,

On Wed, Jun 18, 2014 at 09:10:09PM +0100, Colin Cross wrote:

include/linux/sched.h implements TASK_SIZE_OF as TASK_SIZE if it
is not set by the architecture headers.  TASK_SIZE uses the
current task to determine the size of the virtual address space.
On a 64-bit kernel this will cause reading /proc/pid/pagemap of a
64-bit process from a 32-bit process to return EOF when it reads
past 0xffffffff.

Implement TASK_SIZE_OF exactly the same as TASK_SIZE with
test_tsk_thread_flag instead of test_thread_flag.

Looks sane to me.

  Acked-by: Will Deacon [off-list ref]

I take it you're being bitten by this in real software, hence the CC stable
tag?

Will