From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932251AbcFGHXI (ORCPT ); Tue, 7 Jun 2016 03:23:08 -0400 Received: from mailout3.w1.samsung.com ([210.118.77.13]:39450 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751399AbcFGHXF (ORCPT ); Tue, 7 Jun 2016 03:23:05 -0400 X-AuditID: cbfec7f4-f796c6d000001486-6c-57567656574d Subject: Re: [RESEND PATCH v2] power_supply: power_supply_read_temp only if use_cnt > 0 To: Rhyland Klein , Sebastian Reichel , Dmitry Eremin-Solenikov , David Woodhouse References: <1465232216-12625-1-git-send-email-rklein@nvidia.com> Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Jon Hunter , stable@vger.kernel.org From: Krzysztof Kozlowski X-Enigmail-Draft-Status: N1110 Message-id: <57567654.5060503@samsung.com> Date: Tue, 07 Jun 2016 09:23:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-version: 1.0 In-reply-to: <1465232216-12625-1-git-send-email-rklein@nvidia.com> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrMLMWRmVeSWpSXmKPExsVy+t/xy7phZWHhBrPWqlpMevKe2WLiysnM Fi2zFrFYvH5haHF51xw2i8+9Rxgtlh1fzWpxeneJxYKNjxgdOD12zrrL7rF5hZbHplWdbB69 ze/YPPq2rGL0+LxJLoAtissmJTUnsyy1SN8ugSvjSONbxoI1YhU7u7YzNzAuF+pi5OSQEDCR WHr4GTOELSZx4d56ti5GLg4hgaWMEi86OtghnGeMEofWzWYFqRIWiJS4/uM1I0hCRGAJo8TP HY2MIAkhAUeJn5fPgtnMAuUSd863sYDYbALGEpuXL2GDWCEn0ds9CSzOK6AlcbD3NJjNIqAq cfXpHbBeUYEIiVnbfzBB1AhK/Jh8D6yGU8BJYnrfUaAjOIDm60ncv6gFsUpeYvOat8wTGAVn IemYhVA1C0nVAkbmVYyiqaXJBcVJ6bmGesWJucWleel6yfm5mxghUfFlB+PiY1aHGAU4GJV4 eAW+h4YLsSaWFVfmHmKU4GBWEuGdVhQWLsSbklhZlVqUH19UmpNafIhRmoNFSZx37q73IUIC 6YklqdmpqQWpRTBZJg5OqQbGSX5z1/Xo3P3M9GSm1/pvyut196elSp7da+O5VSnpi/uFKznX Gcp6ZZyehbLe8nPLdbwkrfh6/+RLHywmssRwye30uLZG+/HvDMeP8ZUV69oCXTTniFyZ4heV O+vVTa7au+d2KxzkeqP74epngZRFDVd6Y1yORqSqhDsr3nLzP+13eM6maQJGSizFGYmGWsxF xYkAv4VGkoYCAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/06/2016 06:56 PM, Rhyland Klein wrote: > Add check to power_supply_read_temp() to only use the power_supply > get_property() callback if the use_cnt is > 0. The use_cnt will > be incremented at the end of __power_supply_register, so this will > block to case where get_property can be called before the supply > is fully registered. This fixes the issue show in the stack below: > > [ 1.452598] power_supply_read_temp+0x78/0x80 > [ 1.458680] thermal_zone_get_temp+0x5c/0x11c > [ 1.464765] thermal_zone_device_update+0x34/0xb4 > [ 1.471195] thermal_zone_device_register+0x87c/0x8cc > [ 1.477974] __power_supply_register+0x364/0x424 > [ 1.484317] power_supply_register_no_ws+0x10/0x18 > [ 1.490833] bq27xxx_battery_setup+0x10c/0x164 > [ 1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0 > [ 1.503435] i2c_device_probe+0x174/0x240 > [ 1.509172] driver_probe_device+0x1fc/0x29c > [ 1.515167] __driver_attach+0xa4/0xa8 > [ 1.520643] bus_for_each_dev+0x58/0x98 > [ 1.526204] driver_attach+0x20/0x28 > [ 1.531505] bus_add_driver+0x1c8/0x22c > [ 1.537067] driver_register+0x68/0x108 > [ 1.542630] i2c_register_driver+0x38/0x7c > [ 1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20 > [ 1.555321] do_one_initcall+0x38/0x12c > [ 1.560886] kernel_init_freeable+0x148/0x1ec > [ 1.566972] kernel_init+0x10/0xfc > [ 1.572101] ret_from_fork+0x10/0x40 > > Cc: stable@vger.kernel.org > Signed-off-by: Rhyland Klein And maybe: Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core") > --- > v2: > - Added cc stable > - changed return to -EAGAIN in case of use_cnt < 1 > - Removed WARNING > - return value check added in additional patch: > "thermal: helpers: Check return value of get_temp" > > drivers/power/power_supply_core.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c > index 456987c88baa..bbd80631f31e 100644 > --- a/drivers/power/power_supply_core.c > +++ b/drivers/power/power_supply_core.c > @@ -561,11 +561,15 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd, > { > struct power_supply *psy; > union power_supply_propval val; > - int ret; > + int ret = -EAGAIN; > > WARN_ON(tzd == NULL); > + > psy = tzd->devdata; > - ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val); > + > + if (atomic_read(&psy->use_cnt) > 0) > + ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, > + &val); How about using just power_supply_get_property() and convert return value to EAGAIN? Anyway probably such check should be present also on other get_property() calls, like thermal cooling path. Best regards, Krzysztof