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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Aaro Koskinen <aaro.koskinen@iki.fi>,
        Felipe Balbi <felipe.balbi@linux.intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 23/88] USB: omap_udc: fix crashes on probe error and module removal
Date:   Fri, 14 Dec 2018 12:59:57 +0100
Message-Id: <20181214115704.037531403@linuxfoundation.org>
In-Reply-To: <20181214115702.151309521@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 99f700366fcea1aa2fa3c49c99f371670c3c62f8 ]

We currently crash if usb_add_gadget_udc_release() fails, since the
udc->done is not initialized until in the remove function.
Furthermore, on module removal the udc data is accessed although
the release function is already triggered by usb_del_gadget_udc()
early in the function.

Fix by rewriting the release and remove functions, basically moving
all the cleanup into the release function, and doing the completion
only in the module removal case.

The patch fixes omap_udc module probe with a failing gadged, and also
allows the removal of omap_udc. Tested by running "modprobe omap_udc;
modprobe -r omap_udc" in a loop.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/udc/omap_udc.c | 50 ++++++++++++-------------------
 1 file changed, 19 insertions(+), 31 deletions(-)

diff --git a/drivers/usb/gadget/udc/omap_udc.c b/drivers/usb/gadget/udc/omap_udc.c
index b25eac2dcaf8..da1030f69145 100644
--- a/drivers/usb/gadget/udc/omap_udc.c
+++ b/drivers/usb/gadget/udc/omap_udc.c
@@ -2612,9 +2612,22 @@ omap_ep_setup(char *name, u8 addr, u8 type,
 
 static void omap_udc_release(struct device *dev)
 {
-	complete(udc->done);
+	pullup_disable(udc);
+	if (!IS_ERR_OR_NULL(udc->transceiver)) {
+		usb_put_phy(udc->transceiver);
+		udc->transceiver = NULL;
+	}
+	omap_writew(0, UDC_SYSCON1);
+	remove_proc_file();
+	if (udc->dc_clk) {
+		if (udc->clk_requested)
+			omap_udc_enable_clock(0);
+		clk_put(udc->hhc_clk);
+		clk_put(udc->dc_clk);
+	}
+	if (udc->done)
+		complete(udc->done);
 	kfree(udc);
-	udc = NULL;
 }
 
 static int
@@ -2919,12 +2932,8 @@ static int omap_udc_probe(struct platform_device *pdev)
 	}
 
 	create_proc_file();
-	status = usb_add_gadget_udc_release(&pdev->dev, &udc->gadget,
-			omap_udc_release);
-	if (!status)
-		return 0;
-
-	remove_proc_file();
+	return usb_add_gadget_udc_release(&pdev->dev, &udc->gadget,
+					  omap_udc_release);
 
 cleanup1:
 	kfree(udc);
@@ -2951,36 +2960,15 @@ static int omap_udc_remove(struct platform_device *pdev)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
 
-	if (!udc)
-		return -ENODEV;
-
-	usb_del_gadget_udc(&udc->gadget);
-	if (udc->driver)
-		return -EBUSY;
-
 	udc->done = &done;
 
-	pullup_disable(udc);
-	if (!IS_ERR_OR_NULL(udc->transceiver)) {
-		usb_put_phy(udc->transceiver);
-		udc->transceiver = NULL;
-	}
-	omap_writew(0, UDC_SYSCON1);
-
-	remove_proc_file();
+	usb_del_gadget_udc(&udc->gadget);
 
-	if (udc->dc_clk) {
-		if (udc->clk_requested)
-			omap_udc_enable_clock(0);
-		clk_put(udc->hhc_clk);
-		clk_put(udc->dc_clk);
-	}
+	wait_for_completion(&done);
 
 	release_mem_region(pdev->resource[0].start,
 			pdev->resource[0].end - pdev->resource[0].start + 1);
 
-	wait_for_completion(&done);
-
 	return 0;
 }
 
-- 
2.19.1