Re: [PATCH] mm acct accounting fix

[Hugh Dickins]

On Wed, 11 May 2005, Kirill Korotaev wrote:

> Sorry, forgot to write that all these patches are against 2.6.12-rc4...
> 
> This patch fixes mm->total_vm and mm->locked_vm acctounting in case
> when move_page_tables() fails inside move_vma().
> 
> Signed-Off-By: Kirill Korotaev <dev@xxxxx>
> 
> --- ./mm/mremap.c.mmacct	2005-05-10 16:10:40.000000000 +0400
> +++ ./mm/mremap.c	2005-05-10 18:12:13.000000000 +0400
> @@ -213,6 +213,7 @@ static unsigned long move_vma(struct vm_
>  		old_len = new_len;
>  		old_addr = new_addr;
>  		new_addr = -ENOMEM;
> +		new_len = 0;
>  	}
>  
>  	/* Conceal VM_ACCOUNT so old reservation is not undone */

Are you sure?

The way it's supposed to work is that the do_munmap(,,old_len) which
follows, which normally unmaps the area moved from, when unsuccessful
unmaps the area moved to: which will "mistakenly" decrement total_vm etc.
by old_len, which needs to be bumped back up by that amount before leaving.

Hugh
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