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Message-ID: <9153261627a0f84b996e023f1349a2bc06dd03ee.camel@redhat.com>
Subject: [PATCH v3] libertas: Fix a double free in if_spi_c2h_data()
From:   Dan Williams <dcbw@redhat.com>
To:     Kalle Valo <kvalo@codeaurora.org>
Cc:     Philip Rakity <prakity@yahoo.com>,
        libertas-dev@lists.infradead.org, kernel-janitors@vger.kernel.org,
        linux-wireless@vger.kernel.org, Lubomir Rintel <lkundrak@v3.sk>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Allison Randal <allison@lohutok.net>
Date:   Wed, 24 Jul 2019 09:38:15 -0500
In-Reply-To: <ee4472e4728becc9713962ba264742cb1f337098.camel@redhat.com>
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         <20190626132340.GE28859@kadam>
         <e679c9f99d6952f82924c71f036e4a196d0e72d4.camel@redhat.com>
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The lbs_process_rxed_packet() frees the skb.  It didn't originally, but
we fixed it in commit f54930f36311 ("libertas: don't leak skb on receive
error").

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dan Williams <dcbw@redhat.com>
---

Kalle: sorry about the build error; previous version of the patch before I fixed it.
Here's the correct one.

 drivers/net/wireless/marvell/libertas/if_spi.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/marvell/libertas/if_spi.c b/drivers/net/wireless/marvell/libertas/if_spi.c
index 27067e79e83fe..d07fe82c557e8 100644
--- a/drivers/net/wireless/marvell/libertas/if_spi.c
+++ b/drivers/net/wireless/marvell/libertas/if_spi.c
@@ -766,19 +766,15 @@ static int if_spi_c2h_data(struct if_spi_card *card)
 
 	/* Read the data from the WLAN module into our skb... */
 	err = spu_read(card, IF_SPI_DATA_RDWRPORT_REG, data, ALIGN(len, 4));
-	if (err)
-		goto free_skb;
+	if (err) {
+		dev_kfree_skb(skb);
+		goto out;
+	}
 
 	/* pass the SKB to libertas */
 	err = lbs_process_rxed_packet(card->priv, skb);
-	if (err)
-		goto free_skb;
+	/* lbs_process_rxed_packet() consumes the skb */
 
-	/* success */
-	goto out;
-
-free_skb:
-	dev_kfree_skb(skb);
 out:
 	if (err)
 		netdev_err(priv->dev, "%s: err=%d\n", __func__, err);
-- 
2.20.1