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Received-SPF: Fail (protection.outlook.com: domain of arri.de does not designate 217.111.95.7 as permitted sender) receiver=protection.outlook.com; client-ip=217.111.95.7; helo=mta.arri.de; Received: from mta.arri.de (217.111.95.7) by DU6PEPF0000B620.mail.protection.outlook.com (10.167.8.136) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8048.13 via Frontend Transport; Mon, 7 Oct 2024 15:44:18 +0000 Received: from n9w6sw14.localnet (192.168.54.124) by mta.arri.de (10.10.18.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Mon, 7 Oct 2024 17:44:18 +0200 From: Christian Eggers To: Jonathan Cameron , Lars-Peter Clausen , Michael Hennerich , Alisa-Dariana Roman , Peter Rosin , Paul Cercueil , Sebastian Reichel , Matteo Martelli CC: , , , , Matteo Martelli Subject: Re: [PATCH v2 4/7] iio: as73211: copy/release available integration times to fix race Date: Mon, 7 Oct 2024 17:44:17 +0200 Message-ID: <2287601.vFx2qVVIhK@n9w6sw14> Organization: Arnold & Richter Cine Technik GmbH & Co. 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So can you please update the documentation of this member? I can perform some testing f=FCr as73211, but I would like to wait until the "copy data twice" question has been solved. IMHO a solution like Nuno proposed may be easier to understand. regards, Christian On Monday, 7 October 2024, 10:37:13 CEST, Matteo Martelli wrote: > While available integration times are being printed to sysfs by iio core > (iio_read_channel_info_avail), the sampling frequency might be changed. > This could cause the buffer shared with iio core to be corrupted. To > prevent it, make a copy of the integration times buffer and free it in > the read_avail_release_resource callback. >=20 > Signed-off-by: Matteo Martelli > --- > drivers/iio/light/as73211.c | 22 +++++++++++++++++++--- > 1 file changed, 19 insertions(+), 3 deletions(-) >=20 > diff --git a/drivers/iio/light/as73211.c b/drivers/iio/light/as73211.c > index be0068081ebbbb37fdfb252b67a77b302ff725f6..27bc8cb791039944662a74fc7= 2f09e2c3642cfa6 100644 > --- a/drivers/iio/light/as73211.c > +++ b/drivers/iio/light/as73211.c > @@ -493,17 +493,32 @@ static int as73211_read_avail(struct iio_dev *indio= _dev, struct iio_chan_spec co > *type =3D IIO_VAL_INT; > return IIO_AVAIL_LIST; > =20 > - case IIO_CHAN_INFO_INT_TIME: > + case IIO_CHAN_INFO_INT_TIME: { > *length =3D ARRAY_SIZE(data->int_time_avail); > - *vals =3D data->int_time_avail; > *type =3D IIO_VAL_INT_PLUS_MICRO; > - return IIO_AVAIL_LIST; > =20 > + guard(mutex)(&data->mutex); > + > + *vals =3D kmemdup_array(data->int_time_avail, *length, > + sizeof(int), GFP_KERNEL); > + if (!*vals) > + return -ENOMEM; > + > + return IIO_AVAIL_LIST; > + } > default: > return -EINVAL; > } > } > =20 > +static void as73211_read_avail_release_res(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + const int *vals, long mask) > +{ > + if (mask =3D=3D IIO_CHAN_INFO_INT_TIME) > + kfree(vals); > +} > + > static int _as73211_write_raw(struct iio_dev *indio_dev, > struct iio_chan_spec const *chan __always_unused, > int val, int val2, long mask) > @@ -699,6 +714,7 @@ static irqreturn_t as73211_trigger_handler(int irq __= always_unused, void *p) > static const struct iio_info as73211_info =3D { > .read_raw =3D as73211_read_raw, > .read_avail =3D as73211_read_avail, > + .read_avail_release_resource =3D as73211_read_avail_release_res, > .write_raw =3D as73211_write_raw, > }; > =20 >=20 >=20