linux-kernel - Re: [patch] exofs: confusion between kmap() and kmap

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Message-ID: <4BE68B86.50707@panasas.com>
Date:	Sun, 09 May 2010 13:16:38 +0300
From:	Boaz Harrosh <bharrosh@...asas.com>
To:	Dan Carpenter <error27@...il.com>,
	Benny Halevy <bhalevy@...asas.com>,
	Avishay Traeger <avishay@...il.com>, osd-dev@...n-osd.org,
	linux-kernel@...r.kernel.org
Subject: Re: [patch] exofs: confusion between kmap() and kmap_atomic() api

On 05/07/2010 12:05 PM, Dan Carpenter wrote:
> For kmap_atomic() we call kunmap_atomic() on the returned pointer.
> That's different from kmap() and kunmap() and so it's easy to get them
> backwards.
> 
> Signed-off-by: Dan Carpenter <error27@...il.com>
> 

Thank you Dan, I'll push it ASAP. 

Looks like a bad bug. So this is actually a leak, right? kunmap_atomic
would detect the bad pointer and do nothing?

Thanks again
Boaz

> diff --git a/fs/exofs/dir.c b/fs/exofs/dir.c
> index 4cfab1c..d91e9d8 100644
> --- a/fs/exofs/dir.c
> +++ b/fs/exofs/dir.c
> @@ -608,7 +608,7 @@ int exofs_make_empty(struct inode *inode, struct inode *parent)
>  	de->inode_no = cpu_to_le64(parent->i_ino);
>  	memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
>  	exofs_set_de_type(de, inode);
> -	kunmap_atomic(page, KM_USER0);
> +	kunmap_atomic(kaddr, KM_USER0);
>  	err = exofs_commit_chunk(page, 0, chunk_size);
>  fail:
>  	page_cache_release(page);

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