linux-kernel - Re: Patch "percpu: fix a memory leak in pcpu_extend_area_map()" has been added to the 2.6.35-stable tree

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Date:	Thu, 16 Sep 2010 23:39:02 +0200
From:	"Stefan Lippers-Hollmann" <s.L-H@....de>
To:	gregkh@...e.de
Cc:	linux-kernel@...r.kernel.org, shijie8@...il.com, tj@...nel.org,
	stable@...nel.org
Subject: Re: Patch "percpu: fix a memory leak in pcpu_extend_area_map()" has been added to the 2.6.35-stable tree

Hi

On Thursday 16 September 2010, gregkh@...e.de wrote:
> This is a note to let you know that I've just added the patch titled
>     percpu: fix a memory leak in pcpu_extend_area_map()
> to the 2.6.35-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
[...]
> From a002d148426f40bc2b7dc066982eb177cdebeaaa Mon Sep 17 00:00:00 2001
> From: Huang Shijie <shijie8@...il.com>
> Date: Sun, 8 Aug 2010 14:39:07 +0200
> Subject: percpu: fix a memory leak in pcpu_extend_area_map()
> 
> From: Huang Shijie <shijie8@...il.com>
> 
> commit a002d148426f40bc2b7dc066982eb177cdebeaaa upstream.
> 
> The original code did not free the old map.  This patch fixes it.
> 
> tj: use @old as memcpy source instead of @chunk->map, and indentation
>     and description update

This patch, as part of the current -stable queue-2.6.35, breaks booting for
me on nforce4/ AMD64 X2. Unfortunately it fails even before the serial 
console is initialized and the only messages shown on screen are:

Decompressing Linux... Parsing ELF... done.
Booting kernel.

[...]
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -390,7 +390,9 @@ static int pcpu_extend_area_map(struct p
>  		goto out_unlock;
>  
>  	old_size = chunk->map_alloc * sizeof(chunk->map[0]);
> -	memcpy(new, chunk->map, old_size);
> +	old = chunk->map;
> +
> +	memcpy(new, old, old_size);
>  
>  	/*
>  	 * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is

Reverting just this patch from the current queue-2.6.35 fixes the issue for
me; gzipped kernel config (amd64) attached.

Regards
	Stefan Lippers-Hollmann

Download attachment "config-2.6.35-4.slh.11.9-aptosid-amd64.gz" of type "application/x-gzip" (28163 bytes)