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

From: WU Fengguang
Date: Sun Aug 12 2007 - 20:24:01 EST


On Sun, Aug 12, 2007 at 08:21:43PM +0400, Cyrill Gorcunov wrote:
> [Alan Cox - Sun, Aug 12, 2007 at 04:17:44PM +0100]
> | Try this (it compiles but isnt tested). Its a weekend here, the sun is
> | shining, the beach is a short walk, and I have more interesting things to
> | do right now 8)
> |
> |
[...]
> | -int __vm_enough_memory(long pages, int cap_sys_admin)
> | +int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
> | {
> | unsigned long free, allowed;
> |
> | @@ -166,7 +166,7 @@
> |
> | /* Don't let a single process grow too big:
> | leave 3% of the size of this process for other processes */
> | - allowed -= current->mm->total_vm / 32;
> | + allowed -= mm->total_vm / 32;
>
> So mm->total_vm is 0 for __bprm_mm_init case. Is that ok? Or I miss
> something?

Yeah, Alan adds mm to the interfaces and leaves us the question of
"what mm to pass in when current->mm == NULL?" ;)

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