Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 652/879] RDMA/rxe: Fix an error handling path in rxe_get_mcg()
Date:   Tue,  7 Jun 2022 19:02:50 +0200
Message-Id: <20220607165021.772480272@linuxfoundation.org>
In-Reply-To: <20220607165002.659942637@linuxfoundation.org>
References: <20220607165002.659942637@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

[ Upstream commit 7f60951ff4d1664dfa2c304d144d195989199ef3 ]

The commit in the Fixes tag has shuffled some code.
Now 'mcg_num' is incremented before the kzalloc(). So if the memory
allocation fails, this increment must be undone.

Fixes: a926a903b7dc ("RDMA/rxe: Do not call dev_mc_add/del() under a spinlock")
Link: https://lore.kernel.org/r/fe137cd8b1f17593243aa73d59c18ea71ab9ee36.1653225896.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/sw/rxe/rxe_mcast.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
index 873a9b10307c..86cc2e18a7fd 100644
--- a/drivers/infiniband/sw/rxe/rxe_mcast.c
+++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
@@ -206,8 +206,10 @@ static struct rxe_mcg *rxe_get_mcg(struct rxe_dev *rxe, union ib_gid *mgid)
 
 	/* speculative alloc of new mcg */
 	mcg = kzalloc(sizeof(*mcg), GFP_KERNEL);
-	if (!mcg)
-		return ERR_PTR(-ENOMEM);
+	if (!mcg) {
+		err = -ENOMEM;
+		goto err_dec;
+	}
 
 	spin_lock_bh(&rxe->mcg_lock);
 	/* re-check to see if someone else just added it */
-- 
2.35.1