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From:   Dongliang Mu <mudongliangabcd@gmail.com>
To:     Alexander Aring <alex.aring@gmail.com>,
        Stefan Schmidt <stefan@datenfreihafen.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     Dongliang Mu <mudongliangabcd@gmail.com>,
        Alexander Aring <aring@mojatatu.com>,
        linux-wpan@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] ieee802154: hwsim: fix memory leak in __pskb_copy_fclone
Date:   Tue, 13 Jul 2021 13:40:18 +0800
Message-Id: <20210713054019.409273-1-mudongliangabcd@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

hwsim_hw_xmit fails to deallocate the newskb copied by pskb_copy. Fix
this by adding kfree_skb after ieee802154_rx_irqsafe.

  [<ffffffff836433fb>] __alloc_skb+0x22b/0x250 net/core/skbuff.c:414
  [<ffffffff8364ad95>] __pskb_copy_fclone+0x75/0x360 net/core/skbuff.c:1609
  [<ffffffff82ae65e3>] __pskb_copy include/linux/skbuff.h:1176 [inline]
  [<ffffffff82ae65e3>] pskb_copy include/linux/skbuff.h:3207 [inline]
  [<ffffffff82ae65e3>] hwsim_hw_xmit+0xd3/0x140 drivers/net/ieee802154/mac802154_hwsim.c:132
  [<ffffffff83ff8f47>] drv_xmit_async net/mac802154/driver-ops.h:16 [inline]
  [<ffffffff83ff8f47>] ieee802154_tx+0xc7/0x190 net/mac802154/tx.c:83
  [<ffffffff83ff9138>] ieee802154_subif_start_xmit+0x58/0x70 net/mac802154/tx.c:132
  [<ffffffff83670b82>] __netdev_start_xmit include/linux/netdevice.h:4944 [inline]
  [<ffffffff83670b82>] netdev_start_xmit include/linux/netdevice.h:4958 [inline]
  [<ffffffff83670b82>] xmit_one net/core/dev.c:3658 [inline]
  [<ffffffff83670b82>] dev_hard_start_xmit+0xe2/0x330 net/core/dev.c:3674
  [<ffffffff83718028>] sch_direct_xmit+0xf8/0x520 net/sched/sch_generic.c:342
  [<ffffffff8367193b>] __dev_xmit_skb net/core/dev.c:3874 [inline]
  [<ffffffff8367193b>] __dev_queue_xmit+0xa3b/0x1360 net/core/dev.c:4241
  [<ffffffff83ff5437>] dgram_sendmsg+0x437/0x570 net/ieee802154/socket.c:682
  [<ffffffff836345b6>] sock_sendmsg_nosec net/socket.c:702 [inline]
  [<ffffffff836345b6>] sock_sendmsg+0x56/0x80 net/socket.c:722

Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
 drivers/net/ieee802154/mac802154_hwsim.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c
index ebc976b7fcc2..d97ed033ac77 100644
--- a/drivers/net/ieee802154/mac802154_hwsim.c
+++ b/drivers/net/ieee802154/mac802154_hwsim.c
@@ -132,9 +132,11 @@ static int hwsim_hw_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
 			struct sk_buff *newskb = pskb_copy(skb, GFP_ATOMIC);
 
 			einfo = rcu_dereference(e->info);
-			if (newskb)
+			if (newskb) {
 				ieee802154_rx_irqsafe(e->endpoint->hw, newskb,
 						      einfo->lqi);
+				kfree_skb(newskb);
+			}
 		}
 	}
 	rcu_read_unlock();
-- 
2.25.1