[PATCH 3.16 128/357] uwb: init beacon cache entry before registering uwb device

From: Greg Kroah-Hartman
Date: Fri Oct 03 2014 - 17:38:41 EST


3.16-stable review patch. If anyone has any objections, please let me know.

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

From: Thomas Pugliese <thomas.pugliese@xxxxxxxxx>

commit 675f0ab2fe5a0f7325208e60b617a5f32b86d72c upstream.

Make sure the uwb_dev->bce entry is set before calling uwb_dev_add in
uwbd_dev_onair so that usermode will only see the device after it is
properly initialized. This fixes a kernel panic that can occur if
usermode tries to access the IEs sysfs attribute of a UWB device before
the driver has had a chance to set the beacon cache entry.

Signed-off-by: Thomas Pugliese <thomas.pugliese@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/uwb/lc-dev.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

--- a/drivers/uwb/lc-dev.c
+++ b/drivers/uwb/lc-dev.c
@@ -431,16 +431,19 @@ void uwbd_dev_onair(struct uwb_rc *rc, s
uwb_dev->mac_addr = *bce->mac_addr;
uwb_dev->dev_addr = bce->dev_addr;
dev_set_name(&uwb_dev->dev, "%s", macbuf);
+
+ /* plug the beacon cache */
+ bce->uwb_dev = uwb_dev;
+ uwb_dev->bce = bce;
+ uwb_bce_get(bce); /* released in uwb_dev_sys_release() */
+
result = uwb_dev_add(uwb_dev, &rc->uwb_dev.dev, rc);
if (result < 0) {
dev_err(dev, "new device %s: cannot instantiate device\n",
macbuf);
goto error_dev_add;
}
- /* plug the beacon cache */
- bce->uwb_dev = uwb_dev;
- uwb_dev->bce = bce;
- uwb_bce_get(bce); /* released in uwb_dev_sys_release() */
+
dev_info(dev, "uwb device (mac %s dev %s) connected to %s %s\n",
macbuf, devbuf, rc->uwb_dev.dev.parent->bus->name,
dev_name(rc->uwb_dev.dev.parent));
@@ -448,6 +451,8 @@ void uwbd_dev_onair(struct uwb_rc *rc, s
return;

error_dev_add:
+ bce->uwb_dev = NULL;
+ uwb_bce_put(bce);
kfree(uwb_dev);
return;
}


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