Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932386AbbHCUbj (ORCPT ); Mon, 3 Aug 2015 16:31:39 -0400 Received: from mail-pa0-f48.google.com ([209.85.220.48]:36206 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932251AbbHCUbh (ORCPT ); Mon, 3 Aug 2015 16:31:37 -0400 Date: Mon, 3 Aug 2015 13:31:32 -0700 From: Dmitry Torokhov To: Krzysztof Kozlowski Cc: Jiri Kosina , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, sre@kernel.org, linux-pm@vger.kernel.org, "H.J. Lu" , stable@vger.kernel.org Subject: Re: [PATCH v3] HID: hid-input: Fix accessing freed memory during device disconnect Message-ID: <20150803203132.GE38878@dtor-ws> References: <1438581450-20728-1-git-send-email-k.kozlowski@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1438581450-20728-1-git-send-email-k.kozlowski@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2149 Lines: 68 On Mon, Aug 03, 2015 at 02:57:30PM +0900, Krzysztof Kozlowski wrote: > During unbinding the driver was dereferencing a pointer to memory > already freed by power_supply_unregister(). > > Driver was freeing its internal description of battery through pointers > stored in power_supply structure. However, because the core owns the > power supply instance, after calling power_supply_unregister() this > memory is freed and the driver cannot access these members. > > Fix this by storing the pointer to internal description of battery in a > local variable before calling power_supply_unregister(), so the pointer > remains valid. > > Signed-off-by: Krzysztof Kozlowski > Reported-by: H.J. Lu > Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core") > Cc: > FWIW: Reviewed-by: Dmitry Torokhov > --- > Changes since v2: > 1. Add missing 'const'. > > Changes since v1: > 1. Re-work idea, use local variable instead of devm-like functions > (pointed out by Dmitry Torokhov). > 2. Adjusted subject and commit message. > --- > drivers/hid/hid-input.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c > index 14aebe483219..53aeaf6252c7 100644 > --- a/drivers/hid/hid-input.c > +++ b/drivers/hid/hid-input.c > @@ -462,12 +462,15 @@ out: > > static void hidinput_cleanup_battery(struct hid_device *dev) > { > + const struct power_supply_desc *psy_desc; > + > if (!dev->battery) > return; > > + psy_desc = dev->battery->desc; > power_supply_unregister(dev->battery); > - kfree(dev->battery->desc->name); > - kfree(dev->battery->desc); > + kfree(psy_desc->name); > + kfree(psy_desc); > dev->battery = NULL; > } > #else /* !CONFIG_HID_BATTERY_STRENGTH */ > -- > 1.9.1 > -- Dmitry -- 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/