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[79.18.120.72]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-37d7fa7a118sm1304744f8f.4.2024.10.15.04.06.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Oct 2024 04:06:52 -0700 (PDT) From: Matteo Martelli Date: Tue, 15 Oct 2024 13:06:37 +0200 Subject: [PATCH v3 4/5] iio: ad7192: copy/release available filter frequencies to fix race Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241015-iio-read-avail-release-v3-4-ac3e08f25cb3@gmail.com> References: <20241015-iio-read-avail-release-v3-0-ac3e08f25cb3@gmail.com> In-Reply-To: <20241015-iio-read-avail-release-v3-0-ac3e08f25cb3@gmail.com> To: Jonathan Cameron , Lars-Peter Clausen , Michael Hennerich , Alisa-Dariana Roman , Christian Eggers , Peter Rosin , Paul Cercueil , Sebastian Reichel Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-pm@vger.kernel.org, Matteo Martelli X-Mailer: b4 0.14.2 While available filter frequencies 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 filter frequencies buffer and free it in the read_avail_release_resource callback. Signed-off-by: Matteo Martelli --- drivers/iio/adc/ad7192.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c index 7042ddfdfc03ee5ea58ca07fb1943feb6538175b..acf625ced0b21db8d44f77929e8= a875b3c10e1b1 100644 --- a/drivers/iio/adc/ad7192.c +++ b/drivers/iio/adc/ad7192.c @@ -1056,12 +1056,19 @@ static int ad7192_read_avail(struct iio_dev *indio_= dev, *length =3D ARRAY_SIZE(st->scale_avail) * 2; =20 return IIO_AVAIL_LIST; - case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: - *vals =3D (int *)st->filter_freq_avail; + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: { *type =3D IIO_VAL_FRACTIONAL; *length =3D ARRAY_SIZE(st->filter_freq_avail) * 2; =20 + guard(mutex)(&st->lock); + + *vals =3D kmemdup_array((int *)st->filter_freq_avail, *length, + sizeof(int), GFP_KERNEL); + if (!*vals) + return -ENOMEM; + return IIO_AVAIL_LIST; + } case IIO_CHAN_INFO_OVERSAMPLING_RATIO: *vals =3D (int *)st->oversampling_ratio_avail; *type =3D IIO_VAL_INT; @@ -1073,6 +1080,14 @@ static int ad7192_read_avail(struct iio_dev *indio_d= ev, return -EINVAL; } =20 +static void ad7192_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_LOW_PASS_FILTER_3DB_FREQUENCY) + kfree(vals); +} + static int ad7192_update_scan_mode(struct iio_dev *indio_dev, const unsign= ed long *scan_mask) { struct ad7192_state *st =3D iio_priv(indio_dev); @@ -1098,6 +1113,7 @@ static const struct iio_info ad7192_info =3D { .write_raw =3D ad7192_write_raw, .write_raw_get_fmt =3D ad7192_write_raw_get_fmt, .read_avail =3D ad7192_read_avail, + .read_avail_release_resource =3D ad7192_read_avail_release_res, .attrs =3D &ad7192_attribute_group, .validate_trigger =3D ad_sd_validate_trigger, .update_scan_mode =3D ad7192_update_scan_mode, @@ -1108,6 +1124,7 @@ static const struct iio_info ad7194_info =3D { .write_raw =3D ad7192_write_raw, .write_raw_get_fmt =3D ad7192_write_raw_get_fmt, .read_avail =3D ad7192_read_avail, + .read_avail_release_resource =3D ad7192_read_avail_release_res, .validate_trigger =3D ad_sd_validate_trigger, }; =20 @@ -1116,6 +1133,7 @@ static const struct iio_info ad7195_info =3D { .write_raw =3D ad7192_write_raw, .write_raw_get_fmt =3D ad7192_write_raw_get_fmt, .read_avail =3D ad7192_read_avail, + .read_avail_release_resource =3D ad7192_read_avail_release_res, .attrs =3D &ad7195_attribute_group, .validate_trigger =3D ad_sd_validate_trigger, .update_scan_mode =3D ad7192_update_scan_mode, --=20 2.47.0