linux-kernel - [PATCH 5.1 07/70] net: rds: fix memory leak in rds_ib_flush_mr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190609164127.885921304@linuxfoundation.org>
Date:   Sun,  9 Jun 2019 18:41:18 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Zhu Yanjun <yanjun.zhu@...cle.com>,
        Santosh Shilimkar <santosh.shilimkar@...cle.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 5.1 07/70] net: rds: fix memory leak in rds_ib_flush_mr_pool

From: Zhu Yanjun <yanjun.zhu@...cle.com>

[ Upstream commit 85cb928787eab6a2f4ca9d2a798b6f3bed53ced1 ]

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 <yanjun.zhu@...cle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@...cle.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/rds/ib_rdma.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -428,12 +428,14 @@ int rds_ib_flush_mr_pool(struct rds_ib_m
 		wait_clean_list_grace();
 
 		list_to_llist_nodes(pool, &unmap_list, &clean_nodes, &clean_tail);
-		if (ibmr_ret)
+		if (ibmr_ret) {
 			*ibmr_ret = llist_entry(clean_nodes, struct rds_ib_mr, llnode);
-
+			clean_nodes = clean_nodes->next;
+		}
 		/* more than one entry in llist nodes */
-		if (clean_nodes->next)
-			llist_add_batch(clean_nodes->next, clean_tail, &pool->clean_list);
+		if (clean_nodes)
+			llist_add_batch(clean_nodes, clean_tail,
+					&pool->clean_list);
 
 	}