IronPort-Data: =?us-ascii?q?A9a23=3A+67MA6MQyhPLZznvrR05lcFynXyQoLVcMsFnjC/?=
 =?us-ascii?q?WdVO+3Toh3zwOmzNLW2nSaKyMNzHwLYslb43io04G7ZfXm99gGjLY11k3ESsS9?=
 =?us-ascii?q?pCt6fd1j6vIF3rLaJWFFSqL1u1GAjX7BJ1yHi+0SiuFaOC79CAmj/HQH9IQNca?=
 =?us-ascii?q?fUsxPbV49IMseoUI78wIJqtYAbemRW2thi/uryyHsEAPNNwpPD44hw/nrRCWDE?=
 =?us-ascii?q?xjFkGhwUlQWPZintbJF/pUfJMp3yaqZdxMUTmTId9NWSdovzJnhlo/Y1xwrTN2?=
 =?us-ascii?q?4kLfnaVBMSbnXVeSMoiMOHfH83V4Z/Wpvuko4HKN0hUN/jzSbn9FzydxLnZKtS?=
 =?us-ascii?q?wY1JbCKk+MYO/VdO3gnbPMcpuSXfhBTtuTWlSUqaUDE2e1jBVstOosY4utfDmR?=
 =?us-ascii?q?H9PheIzcIBjiRluCk0bDhErE0rssmJcjveogYvxlI3DjfD+sgB4LDXo3O5NlFz?=
 =?us-ascii?q?HE8i94mNfTRaOIfdztjbR2GaBpKUn8TCZQjjKKri2P5fjlwtl2Yv+w07nLVwQg?=
 =?us-ascii?q?316LiWPLRe9qXVYBPkkORjnzJ8n6/ARwAMtGbjz2f/RqEhODAtTH6VZofUraxn?=
 =?us-ascii?q?sOGKnX7Knc7UUVQDAXk56LizBPWZj6WEGRMkgJGkET43BXDogHBYiCF?=
IronPort-HdrOrdr: =?us-ascii?q?A9a23=3ArUOV6K+sPtGT5ha5jXVuk+DkI+orL9Y04lQ7?=
 =?us-ascii?q?vn2ZKCYlFvBw8vrCoB1173HJYUkqMk3I9ergBEDiewK4yXcW2/hzAV7KZmCP11?=
 =?us-ascii?q?dAR7sSj7cKrQeBJwTOssZZ1YpFN5N1EcDMCzFB5vrS0U2VFMkBzbC8nJyVuQ?=
 =?us-ascii?q?=3D=3D?=
From:   Li Zhijian <lizhijian@cn.fujitsu.com>
To:     <zyjzyj2000@gmail.com>, <jgg@ziepe.ca>
CC:     <linux-rdma@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <yanjun.zhu@linux.dev>, <rpearsonhpe@gmail.com>,
        Li Zhijian <lizhijian@cn.fujitsu.com>,
        Jason Gunthorpe <jgg@nvidia.com>
Subject: [PATCH v2] RDMA/rxe: Prevent from double freeing rxe_map_set
Date:   Tue, 28 Dec 2021 09:44:06 +0800
Message-ID: <20211228014406.1033444-1-lizhijian@cn.fujitsu.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 7BIT
Content-Type:   text/plain; charset=US-ASCII
Precedence: bulk

a same rxe_map_set could be freed twice:
rxe_reg_user_mr()
  -> rxe_mr_init_user()
    -> rxe_mr_free_map_set() # 1st
  -> rxe_drop_ref()
   ...
    -> rxe_mr_cleanup()
      -> rxe_mr_free_map_set() # 2nd

By convention, we should cleanup/free resources in the error path in the
same function where the resources are alloted in. So rxe_mr_init_user()
doesn't need to free the map_set directly.

In addition, we have to reset map_set to NULL inside rxe_mr_alloc() if needed
to prevent from map_set being double freed in rxe_mr_cleanup().

CC: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
---
V2: Fix it by a simpler way by following suggestion from Bob,
---
 drivers/infiniband/sw/rxe/rxe_mr.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 25c78aade822..7c4cd19a9db2 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -141,6 +141,7 @@ static int rxe_mr_alloc(struct rxe_mr *mr, int num_buf, int both)
 		ret = rxe_mr_alloc_map_set(num_map, &mr->next_map_set);
 		if (ret) {
 			rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
+			mr->cur_map_set = NULL;
 			goto err_out;
 		}
 	}
@@ -214,7 +215,7 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 				pr_warn("%s: Unable to get virtual address\n",
 						__func__);
 				err = -ENOMEM;
-				goto err_cleanup_map;
+				goto err_release_umem;
 			}
 
 			buf->addr = (uintptr_t)vaddr;
@@ -237,8 +238,6 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 
 	return 0;
 
-err_cleanup_map:
-	rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
 err_release_umem:
 	ib_umem_release(umem);
 err_out:
-- 
2.31.1