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From:   Zheyu Ma <zheyuma97@gmail.com>
To:     Jes.Sorensen@gmail.com, kvalo@kernel.org, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com
Cc:     linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Zheyu Ma <zheyuma97@gmail.com>
Subject: [PATCH] rtl8xxxu: Fix the error handling of the probe function
Date:   Sat, 16 Jul 2022 21:04:44 +0800
Message-Id: <20220716130444.2950690-1-zheyuma97@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When the driver fails at ieee80211_alloc_hw() at the probe time, the
driver will free the 'hw' which is not allocated, causing a bug.

The following log can reveal it:

[   15.981294] BUG: KASAN: user-memory-access in mutex_is_locked+0xe/0x40
[   15.981558] Read of size 8 at addr 0000000000001ab0 by task modprobe/373
[   15.982583] Call Trace:
[   15.984282]  ieee80211_free_hw+0x22/0x390
[   15.984446]  rtl8xxxu_probe+0x3a1/0xab30 [rtl8xxxu]

Fix the bug by changing the order of the error handling.

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
 .../wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
index 8b2ca9e8eac6..567ada2e665a 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
@@ -6657,7 +6657,7 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
 	if (!hw) {
 		ret = -ENOMEM;
 		priv = NULL;
-		goto exit;
+		goto err_put_dev;
 	}
 
 	priv = hw->priv;
@@ -6679,24 +6679,24 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
 
 	ret = rtl8xxxu_parse_usb(priv, interface);
 	if (ret)
-		goto exit;
+		goto err_set_intfdata;
 
 	ret = rtl8xxxu_identify_chip(priv);
 	if (ret) {
 		dev_err(&udev->dev, "Fatal - failed to identify chip\n");
-		goto exit;
+		goto err_set_intfdata;
 	}
 
 	ret = rtl8xxxu_read_efuse(priv);
 	if (ret) {
 		dev_err(&udev->dev, "Fatal - failed to read EFuse\n");
-		goto exit;
+		goto err_set_intfdata;
 	}
 
 	ret = priv->fops->parse_efuse(priv);
 	if (ret) {
 		dev_err(&udev->dev, "Fatal - failed to parse EFuse\n");
-		goto exit;
+		goto err_set_intfdata;
 	}
 
 	rtl8xxxu_print_chipinfo(priv);
@@ -6704,12 +6704,12 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
 	ret = priv->fops->load_firmware(priv);
 	if (ret) {
 		dev_err(&udev->dev, "Fatal - failed to load firmware\n");
-		goto exit;
+		goto err_set_intfdata;
 	}
 
 	ret = rtl8xxxu_init_device(hw);
 	if (ret)
-		goto exit;
+		goto err_set_intfdata;
 
 	hw->wiphy->max_scan_ssids = 1;
 	hw->wiphy->max_scan_ie_len = IEEE80211_MAX_DATA_LEN;
@@ -6759,12 +6759,12 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
 	if (ret) {
 		dev_err(&udev->dev, "%s: Failed to register: %i\n",
 			__func__, ret);
-		goto exit;
+		goto err_set_intfdata;
 	}
 
 	return 0;
 
-exit:
+err_set_intfdata:
 	usb_set_intfdata(interface, NULL);
 
 	if (priv) {
@@ -6772,9 +6772,10 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
 		mutex_destroy(&priv->usb_buf_mutex);
 		mutex_destroy(&priv->h2c_mutex);
 	}
-	usb_put_dev(udev);
 
 	ieee80211_free_hw(hw);
+err_put_dev:
+	usb_put_dev(udev);
 
 	return ret;
 }
-- 
2.25.1