Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933940AbaLKOD2 (ORCPT ); Thu, 11 Dec 2014 09:03:28 -0500 Received: from mga11.intel.com ([192.55.52.93]:35304 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932802AbaLKOD0 (ORCPT ); Thu, 11 Dec 2014 09:03:26 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,557,1413270000"; d="scan'208";a="636133849" Date: Thu, 11 Dec 2014 16:03:07 +0200 From: Mika Westerberg To: Gabriele Mazzotta Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, benjamin.tissoires@redhat.com, aduggan@synaptics.com, jkosina@suse.cz Subject: Re: NULL pointer dereference in i2c-hid Message-ID: <20141211140307.GE1300@lahna.fi.intel.com> References: <31518562.V5Oyo0POsI@xps13> <20141211085801.GR1300@lahna.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141211085801.GR1300@lahna.fi.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 11, 2014 at 10:58:01AM +0200, Mika Westerberg wrote: > On Wed, Dec 10, 2014 at 06:04:51PM +0100, Gabriele Mazzotta wrote: > > my laptop uses a touchpad that needs hid-rmi along with i2c-hid to work. > > i2c-hid and hid-rmi can be loaded and unloaded independelty from each > > other, however since 34f439e4afcd ("HID: i2c-hid: add runtime PM support") > > if I unload hid-rmi and after it I also unload i2c-hid, I get a NULL > > pointer dereference. > > I'll look into this. > > I can reproduce this easily with i2c-hid + hid-multitouch following your > directions. Can you try the below patch? I think we shouldn't free buffers yet in ->stop() because we need the command buffer sending power commands to the device. Also it seems that ->start() re-allocates buffers anyway if maximum size increases. It shouldn't even leak memory as we release buffers at ->remove() anyway. diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index 62cec01937ea..68a8c938feea 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -705,12 +705,7 @@ static int i2c_hid_start(struct hid_device *hid) static void i2c_hid_stop(struct hid_device *hid) { - struct i2c_client *client = hid->driver_data; - struct i2c_hid *ihid = i2c_get_clientdata(client); - hid->claimed = 0; - - i2c_hid_free_buffers(ihid); } static int i2c_hid_open(struct hid_device *hid) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/