From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh.shilimkar@oracle.com Subject: Re: [PATCH 1/1] net: rds: fix memory leak in rds_ib_flush_mr_pool Date: Thu, 6 Jun 2019 08:57:24 -0700 Message-ID: <7519cb35-07b3-e530-0402-67f76c16a6b4@oracle.com> References: <1559808003-1030-1-git-send-email-yanjun.zhu@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1559808003-1030-1-git-send-email-yanjun.zhu@oracle.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org To: Zhu Yanjun , davem@davemloft.net, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com List-Id: linux-rdma@vger.kernel.org On 6/6/19 1:00 AM, Zhu Yanjun wrote: > When the following tests last for several hours, the problem will occur. > > Server: > rds-stress -r 1.1.1.16 -D 1M > Client: > rds-stress -r 1.1.1.14 -s 1.1.1.16 -D 1M -T 30 > > The following will occur. > > " > Starting up.... > tsks tx/s rx/s tx+rx K/s mbi K/s mbo K/s tx us/c rtt us cpu > % > 1 0 0 0.00 0.00 0.00 0.00 0.00 -1.00 > 1 0 0 0.00 0.00 0.00 0.00 0.00 -1.00 > 1 0 0 0.00 0.00 0.00 0.00 0.00 -1.00 > 1 0 0 0.00 0.00 0.00 0.00 0.00 -1.00 > " > From vmcore, we can find that clean_list is NULL. > > From the source code, rds_mr_flushd calls rds_ib_mr_pool_flush_worker. > Then rds_ib_mr_pool_flush_worker calls > " > rds_ib_flush_mr_pool(pool, 0, NULL); > " > Then in function > " > int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, > int free_all, struct rds_ib_mr **ibmr_ret) > " > ibmr_ret is NULL. > > In the source code, > " > ... > list_to_llist_nodes(pool, &unmap_list, &clean_nodes, &clean_tail); > if (ibmr_ret) > *ibmr_ret = llist_entry(clean_nodes, struct rds_ib_mr, llnode); > > /* more than one entry in llist nodes */ > if (clean_nodes->next) > llist_add_batch(clean_nodes->next, clean_tail, &pool->clean_list); > ... > " > When ibmr_ret is NULL, llist_entry is not executed. clean_nodes->next > instead of clean_nodes is added in clean_list. > So clean_nodes is discarded. It can not be used again. > The workqueue is executed periodically. So more and more clean_nodes are > discarded. Finally the clean_list is NULL. > Then this problem will occur. > > Fixes: 1bc144b62524 ("net, rds, Replace xlist in net/rds/xlist.h with llist") > Signed-off-by: Zhu Yanjun > --- Thanks. Acked-by: Santosh Shilimkar