Re: [BUGFIX] NULL pointer dereference in __vm_enough_memory()

From: Cyrill Gorcunov
Date: Mon Aug 13 2007 - 10:45:57 EST


[Alan Cox - Mon, Aug 13, 2007 at 12:22:24PM +0100]
| > Well, as I see, it seems the Alan's patch is correct. We pass
| > newly created mm to security_vm_enough_memory_mm() and get no errors
| > here even for overcommit = 2. But my question was that mm->total_vm
| > = 0 for this case and that is probably valid too I think. What about
| > the thing you pointed about? Well I think security_vm_enough_memory
| > should never be called from kernel thread (we have secrurity_vm_enough_memory_mm
| > for this). But I will check it more closely. Dont get me wrong - I'm not
| > VMM expert and may do errors ;)
|
| A vma has to inserted into an mm struct so we are fine in terms of kernel
| threads. init_bprm showed up a new case where we add vma's to an mm that
| isn't current->mm. The rest of the vm subsystem supports this and there
| are cases for the future (eg the usermode linux mm switching patch) where
| it might matter that we do it right.
|
| Alan
|

ok, thanks for explanation, Alan.

Cyrill

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