On Dec 11 2014 or thereabouts, Peter Wu wrote: > 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().
Well spotted too! > > hid_set_drvdata() is called before wtp_allocate, be consistent and clear > drvdata too on the error path of wtp_allocate. This is not strictly speaking required. We will have a dangling value in hdev->private_data, but this should be overwritten before the next use. Anyway, it makes sense to clean up after a failure, so the patch is Reviewed-by: Benjamin Tissoires <[email protected]> Cheers, Benjamin > > 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
