Balance a hid_device_io_start() call with hid_device_io_stop() in the
error path. This avoids processing of HID reports when the probe fails
which possibly leads to invalid memory access in hid_device_probe() as
report_enum->report_id_hash might already be freed via
hid_close_report().

hid_set_drvdata() is called before wtp_allocate, be consistent and clear
drvdata too on the error path of wtp_allocate.

Signed-off-by: Peter Wu <[email protected]>
---
Hi Andrew,

There are few users of hid_device_io_start/stop, this is the first one
to get start/stop out of sync. Should the comment of
hid_device_io_start() be updated to ensure that hid_device_io_stop()
gets called before probe() returns? Or should the hid-core be changed to
handle this out-of-sync issue:

                if (ret) {
                        if (hdev->io_started))
                                down(&hdev->driver_input_lock);
                        hid_close_report(hdev);
                        hdev->driver = NULL;
                }

Is my observation correct or not that HID reports can arrive during
hid_close_report() when io_started == true?

Kind regards,
Peter
---
 drivers/hid/hid-logitech-hidpp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 4292cc3..2f420c0 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -1121,7 +1121,7 @@ static int hidpp_probe(struct hid_device *hdev, const 
struct hid_device_id *id)
        if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) {
                ret = wtp_allocate(hdev, id);
                if (ret)
-                       return ret;
+                       goto wtp_allocate_fail;
        }
 
        INIT_WORK(&hidpp->work, delayed_work_cb);
@@ -1141,6 +1141,7 @@ static int hidpp_probe(struct hid_device *hdev, const 
struct hid_device_id *id)
        if (id->group != HID_GROUP_LOGITECH_DJ_DEVICE) {
                if (!connected) {
                        hid_err(hdev, "Device not connected");
+                       hid_device_io_stop(hdev);
                        goto hid_parse_fail;
                }
 
@@ -1186,6 +1187,7 @@ hid_hw_start_fail:
 hid_parse_fail:
        cancel_work_sync(&hidpp->work);
        mutex_destroy(&hidpp->send_mutex);
+wtp_allocate_fail:
        hid_set_drvdata(hdev, NULL);
        return ret;
 }
-- 
2.1.3

--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to