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

[Chris Wright]

* Hugh Dickins (hugh@xxxxxxxxxxx) 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
-- 
Linux Security Modules     http://lsm.immunix.org     http://lsm.bkbits.net
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/