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From:   Miaoqian Lin <linmq006@gmail.com>
To:     "Md. Haris Iqbal" <haris.iqbal@ionos.com>,
        Jack Wang <jinpu.wang@ionos.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Danil Kipnis <danil.kipnis@cloud.ionos.com>,
        linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     linmq006@gmail.com
Subject: [PATCH v2] RDMA/rtrs: Fix double free in alloc_clt
Date:   Mon, 24 Jan 2022 12:21:35 +0000
Message-Id: <20220124122135.5745-1-linmq006@gmail.com>
Precedence: bulk

Callback function rtrs_clt_dev_release() in put_device()
calls kfree(clt); to free memory. We shouldn't call kfree(clt) again.

Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
Changes in v2:
- call free_percpu() before put_device() to avoid UAF.
---
 drivers/infiniband/ulp/rtrs/rtrs-clt.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 7c3f98e57889..aff04f566304 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -2739,10 +2739,8 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
 	 */
 	dev_set_uevent_suppress(&clt->dev, true);
 	err = device_register(&clt->dev);
-	if (err) {
-		put_device(&clt->dev);
-		goto err;
-	}
+	if (err)
+		goto err_register;
 
 	clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj);
 	if (!clt->kobj_paths) {
@@ -2764,6 +2762,11 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
 err:
 	free_percpu(clt->pcpu_path);
 	kfree(clt);
+	goto ret;
+err_register:
+	free_percpu(clt->pcpu_path);
+	put_device(&clt->dev);
+ret:
 	return ERR_PTR(err);
 }
 
-- 
2.17.1