Re: [PATCH] kernel/fork.c: VM accounting bugfix (2.6.11-rc3-bk5)

[Chris Wright <chrisw@osdl.org>]

* Hugh Dickins (hugh@veritas.com) wrote:
> dup_mmap's charge starts out at 0 and gets added to each time around
> the loop through vmas; if security_vm_enough_memory fails at any point
> in that loop, we need to vm_unacct_memory the charge already accumulated.

If that's the requirement, then it's broken as is, because there is
nothing accumulating.  len is re-determined each pass, and charge is
reset each pass.  But I think that it's ok, as we only care about the
last pass.  If dup_mmap() fails part way through, the cleanup path should
call unaccount for the (potentially) accounted by not fully setup vma then
call exit_mmap() and clear all the vmas that got accounted for already.
Either way, Mark's patch is not needed, and I don't think anything needs
patching in this area.  Hugh, do you agree?

thanks,
-chris
-- 
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