[Ocfs2-devel] [PATCH v2] ocfs2: fix possible memory leak in dlm_process_recovery_data

[Joseph Qi]

Please consider the belowing case:
dlm_migrate_all_locks -> dlm_empty_lockres -> dlm_migrate_lockres ->
dlm_send_one_lockres, if we have already sent some locks, say
DLM_MAX_MIGRATABLE_LOCKS for the first time, and then
dlm_send_mig_lockres_msg failed because of network down, it will redo
it. During the redo_bucket, the lockres can be hashed and migrated
again.

On 2013/5/3 1:19, Sunil Mushran wrote:
> Do you know under what conditions does it create a new lock when it
> should not?
> 
> This code should only trigger if the lockres is/was mastered on another
> node.
> Meaning this node will not know about the newlock. Meaning that code should
> never trigger.
> 
> 1949                         if (lock->ml.cookie == ml->cookie) {
> This if looks hacky.
> 
> If you have a reproducible case, it may be worthwhile to get some traces
> to see
> under what conditions this happens. Should be straight forward after that.
> 
> Thanks
> Sunil
> 
> 
> 
> On Thu, May 2, 2013 at 5:56 AM, Joseph Qi <joseph.qi at huawei.com
> <mailto:joseph.qi at huawei.com>> wrote:
> 
>     We found a possible memory leak in dlm_process_recovery_data when doing
>     code review. In dlm_process_recovery_data, it creates newlock each time,
>     but don't free when it is bad, and then it will lead to memory leak.
> 
>     Cc: stable at vger.kernel.org <mailto:stable at vger.kernel.org>
>     Signed-off-by: Joseph Qi <joseph.qi at huawei.com> <mailto:joseph.qi at huawei.com>
>     Reviewed-by: Jie Liu <jeff.liu at oracle.com> <mailto:jeff.liu at oracle.com>
> 
>     ---
>      fs/ocfs2/dlm/dlmrecovery.c |    4 ++++
>      1 file changed, 4 insertions(+)
> 
>     diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
>     index eeac97b..9f08523 100644
>     --- a/fs/ocfs2/dlm/dlmrecovery.c
>     +++ b/fs/ocfs2/dlm/dlmrecovery.c
>     @@ -1974,6 +1974,10 @@ skip_lvb:
>      			     res->lockname.len, res->lockname.name <http://lockname.name>, ml->node);
>      			dlm_lockres_set_refmap_bit(dlm, res, ml->node);
>      			added++;
>     +		} else {
>     +			/* Free the new lock if it is bad */
>     +			dlm_lock_put(newlock);
>     +			newlock = NULL;
>      		}
>      		spin_unlock(&res->spinlock);
>      	}
>     -- 
>     1.7.9.7
> 
> 
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