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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        "Shuah Khan" <shuahkh@osg.samsung.com>
Date:   Sat, 22 Sep 2018 01:15:42 +0100
Message-ID: <lsq.1537575342.168616023@decadent.org.uk>
Subject: [PATCH 3.16 06/63] usbip: usbip_host: fix to hold parent lock for
 device_attach() calls
In-Reply-To: <lsq.1537575341.194909669@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.58-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Shuah Khan <shuahkh@osg.samsung.com>

commit 4bfb141bc01312a817d36627cc47c93f801c216d upstream.

usbip_host calls device_attach() without holding dev->parent lock.
Fix it.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/staging/usbip/stub_main.c | 5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/staging/usbip/stub_main.c
+++ b/drivers/staging/usbip/stub_main.c
@@ -205,7 +205,12 @@ static ssize_t rebind_store(struct devic
 	if (!bid)
 		return -ENODEV;
 
+	/* device_attach() callers should hold parent lock for USB */
+	if (bid->udev->dev.parent)
+		device_lock(bid->udev->dev.parent);
 	ret = device_attach(&bid->udev->dev);
+	if (bid->udev->dev.parent)
+		device_unlock(bid->udev->dev.parent);
 	if (ret < 0) {
 		dev_err(&bid->udev->dev, "rebind failed\n");
 		return ret;