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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, Felipe Balbi <balbi@kernel.org>,
        Nadezda Lutovinova <lutovinova@ispras.ru>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 056/133] usb: gadget: mv_u3d: request_irq() after initializing UDC
Date:   Mon, 20 Sep 2021 18:42:14 +0200
Message-Id: <20210920163914.480702186@linuxfoundation.org>
In-Reply-To: <20210920163912.603434365@linuxfoundation.org>
References: <20210920163912.603434365@linuxfoundation.org>
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From: Nadezda Lutovinova <lutovinova@ispras.ru>

[ Upstream commit 2af0c5ffadaf9d13eca28409d4238b4e672942d3 ]

If IRQ occurs between calling  request_irq() and  mv_u3d_eps_init(),
then null pointer dereference occurs since u3d->eps[] wasn't
initialized yet but used in mv_u3d_nuke().

The patch puts registration of the interrupt handler after
initializing of neccesery data.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: 90fccb529d24 ("usb: gadget: Gadget directory cleanup - group UDC drivers")
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Nadezda Lutovinova <lutovinova@ispras.ru>
Link: https://lore.kernel.org/r/20210818141247.4794-1-lutovinova@ispras.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/udc/mv_u3d_core.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/gadget/udc/mv_u3d_core.c b/drivers/usb/gadget/udc/mv_u3d_core.c
index dafe74eb9ade..9ee4a2605dea 100644
--- a/drivers/usb/gadget/udc/mv_u3d_core.c
+++ b/drivers/usb/gadget/udc/mv_u3d_core.c
@@ -1929,14 +1929,6 @@ static int mv_u3d_probe(struct platform_device *dev)
 		goto err_get_irq;
 	}
 	u3d->irq = r->start;
-	if (request_irq(u3d->irq, mv_u3d_irq,
-		IRQF_SHARED, driver_name, u3d)) {
-		u3d->irq = 0;
-		dev_err(&dev->dev, "Request irq %d for u3d failed\n",
-			u3d->irq);
-		retval = -ENODEV;
-		goto err_request_irq;
-	}
 
 	/* initialize gadget structure */
 	u3d->gadget.ops = &mv_u3d_ops;	/* usb_gadget_ops */
@@ -1949,6 +1941,15 @@ static int mv_u3d_probe(struct platform_device *dev)
 
 	mv_u3d_eps_init(u3d);
 
+	if (request_irq(u3d->irq, mv_u3d_irq,
+		IRQF_SHARED, driver_name, u3d)) {
+		u3d->irq = 0;
+		dev_err(&dev->dev, "Request irq %d for u3d failed\n",
+			u3d->irq);
+		retval = -ENODEV;
+		goto err_request_irq;
+	}
+
 	/* external vbus detection */
 	if (u3d->vbus) {
 		u3d->clock_gating = 1;
@@ -1972,8 +1973,8 @@ static int mv_u3d_probe(struct platform_device *dev)
 
 err_unregister:
 	free_irq(u3d->irq, u3d);
-err_request_irq:
 err_get_irq:
+err_request_irq:
 	kfree(u3d->status_req);
 err_alloc_status_req:
 	kfree(u3d->eps);
-- 
2.30.2