On Mon, Feb 8, 2010 at 2:05 PM, KOSAKI Motohiro
[off-list ref] wrote:

quoted

quoted

--- linux-2.6-ozlabs.orig/fs/exec.c
+++ linux-2.6-ozlabs/fs/exec.c

@@ -627,10 +627,13 @@ int setup_arg_pages(struct linux_binprm

                      goto out_unlock;
      }

+     stack_base = min(EXTRA_STACK_VM_PAGES * PAGE_SIZE,
+                      current->signal->rlim[RLIMIT_STACK].rlim_cur -
+                        PAGE_SIZE);

This line is a bit unclear why "- PAGE_SIZE" is necessary.
personally, I like following likes explicit comments.

       stack_expand = EXTRA_STACK_VM_PAGES * PAGE_SIZE;
       stack_lim = ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur);

       /* Initial stack must not cause stack overflow. */
       if (stack_expand + PAGE_SIZE > stack_lim)
               stack_expand = stack_lim - PAGE_SIZE;

note: accessing rlim_cur require ACCESS_ONCE.


Thought?

It's better to use the helper function: rlimit().

AFAIK, stable tree doesn't have rlimit(). but yes, making two patch
(for mainline and for stable) is good opinion.