From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sunil Mushran <sunil.mushran@oracle.com>
Date: Thu, 09 Sep 2010 19:19:13 -0700
Subject: [Ocfs2-devel] [PATCH 1/1] Ocfs2: Handle empty list in
 lockres_seq_start() for dlmdebug.c
In-Reply-To: <1284084993-7767-1-git-send-email-tristan.ye@oracle.com>
References: <1284084993-7767-1-git-send-email-tristan.ye@oracle.com>
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To: ocfs2-devel@oss.oracle.com

Signed-off-by: Sunil Mushran<sunil.mushran@oracle.com>

I am assuming you have tested it. ;)


On 09/09/2010 07:16 PM, Tristan Ye wrote:
> This patch tries to handle the case in which list 'dlm->tracking_list' is
> empty, to avoid accessing an invalid pointer. It fixes the following oops:
>
> http://oss.oracle.com/bugzilla/show_bug.cgi?id=1287
>
> Signed-off-by: Tristan Ye<tristan.ye@oracle.com>
> ---
>   fs/ocfs2/dlm/dlmdebug.c |    9 ++++++++-
>   1 files changed, 8 insertions(+), 1 deletions(-)
>
> diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
> index 5efdd37..901ca52 100644
> --- a/fs/ocfs2/dlm/dlmdebug.c
> +++ b/fs/ocfs2/dlm/dlmdebug.c
> @@ -636,8 +636,14 @@ static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
>   	spin_lock(&dlm->track_lock);
>   	if (oldres)
>   		track_list =&oldres->tracking;
> -	else
> +	else {
>   		track_list =&dlm->tracking_list;
> +		if (list_empty(track_list)) {
> +			dl = NULL;
> +			spin_unlock(&dlm->track_lock);
> +			goto bail;
> +		}
> +	}
>
>   	list_for_each_entry(res, track_list, tracking) {
>   		if (&res->tracking ==&dlm->tracking_list)
> @@ -660,6 +666,7 @@ static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
>   	} else
>   		dl = NULL;
>
> +bail:
>   	/* passed to seq_show */
>   	return dl;
>   }
>