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[82.56.18.47]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4316f570dd5sm57210805e9.3.2024.10.21.05.56.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2024 05:56:25 -0700 (PDT) From: Matteo Martelli Date: Mon, 21 Oct 2024 14:54:14 +0200 Subject: [PATCH v5 1/5] iio: core: add read_avail_release_resource callback 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: <20241021-iio-read-avail-release-v5-1-b168713fab33@gmail.com> References: <20241021-iio-read-avail-release-v5-0-b168713fab33@gmail.com> In-Reply-To: <20241021-iio-read-avail-release-v5-0-b168713fab33@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 Some iio drivers currently share an available info buffer that might be changed while iio core prints it to sysfs. To avoid the buffer corruption, add a release callback to let iio drivers allocate a copy of the available info buffer and later free it in the release callback. Such control is kept in the driver logic so that some driver that needs a big available info buffer might also perform some check to keep the copied buffer around in case no race has occurred. Signed-off-by: Matteo Martelli --- drivers/iio/industrialio-core.c | 14 +++++++++++--- include/linux/iio/iio.h | 4 ++++ 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-cor= e.c index 6a6568d4a2cb3a3f63381d5a6f25a2881b3ba2ed..4aea9de9f15a4d70f9d02fb3d47= df49eef8c8423 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -859,12 +859,20 @@ static ssize_t iio_read_channel_info_avail(struct dev= ice *dev, return ret; switch (ret) { case IIO_AVAIL_LIST: - return iio_format_avail_list(buf, vals, type, length); + ret =3D iio_format_avail_list(buf, vals, type, length); + break; case IIO_AVAIL_RANGE: - return iio_format_avail_range(buf, vals, type); + ret =3D iio_format_avail_range(buf, vals, type); + break; default: - return -EINVAL; + ret =3D -EINVAL; } + + if (indio_dev->info->read_avail_release_resource) + indio_dev->info->read_avail_release_resource( + indio_dev, this_attr->c, vals, this_attr->address); + + return ret; } =20 /** diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h index 3a9b57187a958d6e65c699cf7814df5bac9a99e3..03bb765670a0c5f0129fc677c3a= 4a4cb38f4dad1 100644 --- a/include/linux/iio/iio.h +++ b/include/linux/iio/iio.h @@ -491,6 +491,10 @@ struct iio_info { int *length, long mask); =20 + void (*read_avail_release_resource)(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int *vals, long mask); + int (*write_raw)(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, --=20 2.47.0 From nobody Tue Nov 26 04:35:46 2024 Received: from mail-wr1-f53.google.com (mail-wr1-f53.google.com [209.85.221.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE47A1F5854; Mon, 21 Oct 2024 12:56:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.53 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; 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[82.56.18.47]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4316f5cc401sm55615835e9.43.2024.10.21.05.56.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2024 05:56:26 -0700 (PDT) From: Matteo Martelli Date: Mon, 21 Oct 2024 14:54:15 +0200 Subject: [PATCH v5 2/5] iio: consumers: copy/release available info from producer 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: <20241021-iio-read-avail-release-v5-2-b168713fab33@gmail.com> References: <20241021-iio-read-avail-release-v5-0-b168713fab33@gmail.com> In-Reply-To: <20241021-iio-read-avail-release-v5-0-b168713fab33@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 Consumers need to call the producer's read_avail_release_resource() callback after reading producer's available info. To avoid a race condition with the producer unregistration, change inkern iio_channel_read_avail() so that it copies the available info from the producer and immediately calls its release callback with info_exists locked. Also, modify the users of iio_read_avail_channel_raw() and iio_read_avail_channel_attribute() to free the copied available buffers after calling these functions. To let users free the copied buffer with a cleanup pattern, also add a iio_read_avail_channel_attr_retvals() consumer helper that is equivalent to iio_read_avail_channel_attribute() but stores the available values in the returned variable. Signed-off-by: Matteo Martelli --- drivers/iio/afe/iio-rescale.c | 8 +++ drivers/iio/dac/dpot-dac.c | 8 +++ drivers/iio/inkern.c | 99 ++++++++++++++++++++++++++++--= ---- drivers/iio/multiplexer/iio-mux.c | 8 +++ drivers/power/supply/ingenic-battery.c | 22 +++++--- include/linux/iio/consumer.h | 28 +++++++++- 6 files changed, 147 insertions(+), 26 deletions(-) diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 56e5913ab82d1c045c9ca27012008a4495502cbf..78bb86c291706748b4072a48453= 2ad20c415ff9f 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -249,9 +249,17 @@ static int rescale_read_avail(struct iio_dev *indio_de= v, } } =20 +static void rescale_read_avail_release_res(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int *vals, long mask) +{ + kfree(vals); +} + static const struct iio_info rescale_info =3D { .read_raw =3D rescale_read_raw, .read_avail =3D rescale_read_avail, + .read_avail_release_resource =3D rescale_read_avail_release_res, }; =20 static ssize_t rescale_read_ext_info(struct iio_dev *indio_dev, diff --git a/drivers/iio/dac/dpot-dac.c b/drivers/iio/dac/dpot-dac.c index f36f10bfb6be7863a56b911b5f58671ef530c977..43d68e17fc3a5fca59fad6ccf81= 8eeadfecdb8c1 100644 --- a/drivers/iio/dac/dpot-dac.c +++ b/drivers/iio/dac/dpot-dac.c @@ -108,6 +108,13 @@ static int dpot_dac_read_avail(struct iio_dev *indio_d= ev, return -EINVAL; } =20 +static void dpot_dac_read_avail_release_res(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int *vals, long mask) +{ + kfree(vals); +} + static int dpot_dac_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) @@ -125,6 +132,7 @@ static int dpot_dac_write_raw(struct iio_dev *indio_dev, static const struct iio_info dpot_dac_info =3D { .read_raw =3D dpot_dac_read_raw, .read_avail =3D dpot_dac_read_avail, + .read_avail_release_resource =3D dpot_dac_read_avail_release_res, .write_raw =3D dpot_dac_write_raw, }; =20 diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index 7f325b3ed08fae6674245312cf8f57bb151006c0..7b87d1c57d6fd1258d254192835= aa6cb9355f859 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -760,12 +760,56 @@ static int iio_channel_read_avail(struct iio_channel = *chan, if (!iio_channel_has_available(chan->channel, info)) return -EINVAL; =20 - if (iio_info->read_avail) - return iio_info->read_avail(chan->indio_dev, chan->channel, - vals, type, length, info); + if (iio_info->read_avail) { + const int *vals_tmp; + int ret; + + ret =3D iio_info->read_avail(chan->indio_dev, chan->channel, + &vals_tmp, type, length, info); + if (ret < 0) + return ret; + + /* + * Copy the producer's avail buffer with lock_exists locked to + * avoid possible race with producer unregistration. + */ + *vals =3D kmemdup_array(vals_tmp, *length, sizeof(int), GFP_KERNEL); + if (!*vals) + return -ENOMEM; + + if (iio_info->read_avail_release_resource) + iio_info->read_avail_release_resource( + chan->indio_dev, chan->channel, vals_tmp, info); + + return ret; + } return -EINVAL; } =20 +/* + * iio_channel_read_avail_retvals() is equivalent to iio_channel_read_avai= l() + * but stores the pointer to the buffer of available values in the returned + * variable. Since such buffer must be freed after use, this function lets= the + * user declare a cleanup local variable, e.g.: + * const int *vals =3D __free(kfree) =3D iio_channel_read_avail_retvals(..= .); + */ +static const int *iio_channel_read_avail_retvals(struct iio_channel *chan, + int *type, int *length, + int *avail_type, + enum iio_chan_info_enum info) +{ + const int *vals; + int ret; + + ret =3D iio_channel_read_avail(chan, &vals, type, length, info); + if (ret < 0) + return ERR_PTR(ret); + + *avail_type =3D ret; + + return vals; +} + int iio_read_avail_channel_attribute(struct iio_channel *chan, const int **vals, int *type, int *length, enum iio_chan_info_enum attribute) @@ -780,6 +824,25 @@ int iio_read_avail_channel_attribute(struct iio_channe= l *chan, } EXPORT_SYMBOL_GPL(iio_read_avail_channel_attribute); =20 +const int * +iio_read_avail_channel_attr_retvals(struct iio_channel *chan, int *type, + int *length, int *avail_type, + enum iio_chan_info_enum attribute) +{ + const int *vals; + int ret; + + ret =3D iio_read_avail_channel_attribute(chan, &vals, type, length, + attribute); + if (ret < 0) + return ERR_PTR(ret); + + *avail_type =3D ret; + + return vals; +} +EXPORT_SYMBOL_GPL(iio_read_avail_channel_attr_retvals); + int iio_read_avail_channel_raw(struct iio_channel *chan, const int **vals, int *length) { @@ -789,9 +852,11 @@ int iio_read_avail_channel_raw(struct iio_channel *cha= n, ret =3D iio_read_avail_channel_attribute(chan, vals, &type, length, IIO_CHAN_INFO_RAW); =20 - if (ret >=3D 0 && type !=3D IIO_VAL_INT) + if (ret >=3D 0 && type !=3D IIO_VAL_INT) { /* raw values are assumed to be IIO_VAL_INT */ + kfree(*vals); ret =3D -EINVAL; + } =20 return ret; } @@ -801,15 +866,16 @@ static int iio_channel_read_max(struct iio_channel *c= han, int *val, int *val2, int *type, enum iio_chan_info_enum info) { - const int *vals; int length; - int ret; + int avail_type; =20 - ret =3D iio_channel_read_avail(chan, &vals, type, &length, info); - if (ret < 0) - return ret; + const int *vals __free(kfree) =3D + iio_channel_read_avail_retvals(chan, type, &length, + &avail_type, info); + if (IS_ERR(vals)) + return PTR_ERR(vals); =20 - switch (ret) { + switch (avail_type) { case IIO_AVAIL_RANGE: switch (*type) { case IIO_VAL_INT: @@ -857,15 +923,16 @@ static int iio_channel_read_min(struct iio_channel *c= han, int *val, int *val2, int *type, enum iio_chan_info_enum info) { - const int *vals; int length; - int ret; + int avail_type; =20 - ret =3D iio_channel_read_avail(chan, &vals, type, &length, info); - if (ret < 0) - return ret; + const int *vals __free(kfree) =3D + iio_channel_read_avail_retvals(chan, type, &length, + &avail_type, info); + if (IS_ERR(vals)) + return PTR_ERR(vals); =20 - switch (ret) { + switch (avail_type) { case IIO_AVAIL_RANGE: switch (*type) { case IIO_VAL_INT: diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/ii= o-mux.c index 2953403bef53bbe47a97a8ab1c475ed88d7f86d2..31345437784b01c5d6f8ea70263= f4c2574388e7a 100644 --- a/drivers/iio/multiplexer/iio-mux.c +++ b/drivers/iio/multiplexer/iio-mux.c @@ -142,6 +142,13 @@ static int mux_read_avail(struct iio_dev *indio_dev, return ret; } =20 +static void mux_read_avail_release_res(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int *vals, long mask) +{ + kfree(vals); +} + static int mux_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) @@ -171,6 +178,7 @@ static int mux_write_raw(struct iio_dev *indio_dev, static const struct iio_info mux_info =3D { .read_raw =3D mux_read_raw, .read_avail =3D mux_read_avail, + .read_avail_release_resource =3D mux_read_avail_release_res, .write_raw =3D mux_write_raw, }; =20 diff --git a/drivers/power/supply/ingenic-battery.c b/drivers/power/supply/= ingenic-battery.c index 0a40f425c27723ccec49985b8b5e14a737b6a7eb..5d82c799ba5af3302bfcdfadb5f= 57adf6b12b353 100644 --- a/drivers/power/supply/ingenic-battery.c +++ b/drivers/power/supply/ingenic-battery.c @@ -6,12 +6,14 @@ * based on drivers/power/supply/jz4740-battery.c */ =20 +#include #include #include #include #include #include #include +#include =20 struct ingenic_battery { struct device *dev; @@ -62,8 +64,8 @@ static int ingenic_battery_get_property(struct power_supp= ly *psy, */ static int ingenic_battery_set_scale(struct ingenic_battery *bat) { - const int *scale_raw; - int scale_len, scale_type, best_idx =3D -1, best_mV, max_raw, i, ret; + int scale_len, scale_type, scale_avail_type; + int best_idx =3D -1, best_mV, max_raw, i, ret; u64 max_mV; =20 ret =3D iio_read_max_channel_raw(bat->channel, &max_raw); @@ -72,14 +74,18 @@ static int ingenic_battery_set_scale(struct ingenic_bat= tery *bat) return ret; } =20 - ret =3D iio_read_avail_channel_attribute(bat->channel, &scale_raw, - &scale_type, &scale_len, - IIO_CHAN_INFO_SCALE); - if (ret < 0) { + const int *scale_raw __free(kfree) =3D + iio_read_avail_channel_attr_retvals(bat->channel, + &scale_type, + &scale_len, + &scale_avail_type, + IIO_CHAN_INFO_SCALE); + if (IS_ERR(scale_raw)) { dev_err(bat->dev, "Unable to read channel avail scale\n"); - return ret; + return PTR_ERR(scale_raw); } - if (ret !=3D IIO_AVAIL_LIST || scale_type !=3D IIO_VAL_FRACTIONAL_LOG2) + if (scale_avail_type !=3D IIO_AVAIL_LIST || + scale_type !=3D IIO_VAL_FRACTIONAL_LOG2) return -EINVAL; =20 max_mV =3D bat->info->voltage_max_design_uv / 1000; diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h index 333d1d8ccb37f387fe531577ac5e0bfc7f752cec..188cc64609bd1fd8e0522e69f0b= 65a73b9b1606d 100644 --- a/include/linux/iio/consumer.h +++ b/include/linux/iio/consumer.h @@ -316,7 +316,7 @@ int iio_read_min_channel_raw(struct iio_channel *chan, = int *val); /** * iio_read_avail_channel_raw() - read available raw values from a given c= hannel * @chan: The channel being queried. - * @vals: Available values read back. + * @vals: Available values read back. Must be freed after use. * @length: Number of entries in vals. * * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST. @@ -334,7 +334,7 @@ int iio_read_avail_channel_raw(struct iio_channel *chan, /** * iio_read_avail_channel_attribute() - read available channel attribute v= alues * @chan: The channel being queried. - * @vals: Available values read back. + * @vals: Available values read back. Must be freed after use. * @type: Type of values read back. * @length: Number of entries in vals. * @attribute: info attribute to be read back. @@ -345,6 +345,30 @@ int iio_read_avail_channel_attribute(struct iio_channe= l *chan, const int **vals, int *type, int *length, enum iio_chan_info_enum attribute); =20 + +/** + * iio_read_avail_channel_attr_retvals() - read available channel attr val= ues + * @chan: The channel being queried. + * @type: Type of values read back. + * @length: Number of entries in vals. + * @avail_type: Available type of values read back + * (IIO_AVAIL_RANGE or IIO_AVAIL_LIST). + * @attribute: info attribute to be read back. + * + * This function is equivalent to iio_read_avail_channel_attribute() but s= tores + * the pointer to the buffer of available values in the returned variable. + * Since such buffer must be freed after use, this function lets the user + * declare a cleanup local variable, e.g.: + * const int *vals =3D __free(kfree) =3D iio_read_avail_channel_attr_retva= ls(...); 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[82.56.18.47]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4316f5c2df7sm56628355e9.33.2024.10.21.05.56.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2024 05:56:27 -0700 (PDT) From: Matteo Martelli Date: Mon, 21 Oct 2024 14:54:16 +0200 Subject: [PATCH v5 3/5] iio: pac1921: use read_avail+release APIs instead of custom ext_info 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: <20241021-iio-read-avail-release-v5-3-b168713fab33@gmail.com> References: <20241021-iio-read-avail-release-v5-0-b168713fab33@gmail.com> In-Reply-To: <20241021-iio-read-avail-release-v5-0-b168713fab33@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 The pac1921 driver was exposing the available scale info via an ad-hoc ext_info attribute instead of using the read_avail API. This to avoid a possible race condition: while the available current scales were being printed to sysfs by iio core (iio_read_channel_info_avail), the shunt resistor might have been changed concurrently. Switch to the read_avail+release APIs now that the race condition has been addressed. Signed-off-by: Matteo Martelli --- drivers/iio/adc/pac1921.c | 128 ++++++++++++++++--------------------------= ---- 1 file changed, 45 insertions(+), 83 deletions(-) diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index a96fae546bc1e6d1bf3a0dbe67204c191d77a3ee..f6f8f9122a78d1b5e63d8184203= eb3dae55eb560 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -444,11 +444,52 @@ static int pac1921_read_avail(struct iio_dev *indio_d= ev, *vals =3D pac1921_int_num_samples; *length =3D ARRAY_SIZE(pac1921_int_num_samples); return IIO_AVAIL_LIST; + case IIO_CHAN_INFO_SCALE: + switch (chan->channel) { + case PAC1921_CHAN_VBUS: + *vals =3D (const int *)pac1921_vbus_scales; + *length =3D ARRAY_SIZE(pac1921_vbus_scales) * 2; + *type =3D IIO_VAL_INT_PLUS_NANO; + return IIO_AVAIL_LIST; + + case PAC1921_CHAN_VSENSE: + *vals =3D (const int *)pac1921_vsense_scales; + *length =3D ARRAY_SIZE(pac1921_vsense_scales) * 2; + *type =3D IIO_VAL_INT_PLUS_NANO; + return IIO_AVAIL_LIST; + + case PAC1921_CHAN_CURRENT: { + struct pac1921_priv *priv =3D iio_priv(indio_dev); + + *length =3D ARRAY_SIZE(priv->current_scales) * 2; + *type =3D IIO_VAL_INT_PLUS_NANO; + + guard(mutex)(&priv->lock); + + *vals =3D kmemdup_array((int *)priv->current_scales, + *length, sizeof(int), GFP_KERNEL); + if (!*vals) + return -ENOMEM; + + return IIO_AVAIL_LIST; + } + default: + return -EINVAL; + } default: return -EINVAL; } } =20 +static void pac1921_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_SCALE && + chan->channel =3D=3D PAC1921_CHAN_CURRENT) + kfree(vals); +} + /* * Perform configuration update sequence: set the device into read state, = then * write the config register and set the device back into integration stat= e. @@ -748,6 +789,7 @@ static int pac1921_read_event_value(struct iio_dev *ind= io_dev, static const struct iio_info pac1921_iio =3D { .read_raw =3D pac1921_read_raw, .read_avail =3D pac1921_read_avail, + .read_avail_release_resource =3D pac1921_read_avail_release_res, .write_raw =3D pac1921_write_raw, .write_raw_get_fmt =3D pac1921_write_raw_get_fmt, .read_label =3D pac1921_read_label, @@ -805,88 +847,7 @@ static ssize_t pac1921_write_shunt_resistor(struct iio= _dev *indio_dev, return len; } =20 -/* - * Emit on sysfs the list of available scales contained in scales_tbl - * - * TODO:: this function can be replaced with iio_format_avail_list() if the - * latter will ever be exported. - * - * Must be called with lock held if the scales_tbl can change runtime (e.g= . for - * the current scales table) - */ -static ssize_t pac1921_format_scale_avail(const int (*const scales_tbl)[2], - size_t size, char *buf) -{ - ssize_t len =3D 0; - - for (unsigned int i =3D 0; i < size; i++) { - if (i !=3D 0) { - len +=3D sysfs_emit_at(buf, len, " "); - if (len >=3D PAGE_SIZE) - return -EFBIG; - } - len +=3D sysfs_emit_at(buf, len, "%d.%09d", scales_tbl[i][0], - scales_tbl[i][1]); - if (len >=3D PAGE_SIZE) - return -EFBIG; - } - - len +=3D sysfs_emit_at(buf, len, "\n"); - return len; -} - -/* - * Read available scales for a specific channel - * - * NOTE: using extended info insted of iio.read_avail() because access to - * current scales must be locked as they depend on shunt resistor which may - * change runtime. Caller of iio.read_avail() would access the table unloc= ked - * instead. - */ -static ssize_t pac1921_read_scale_avail(struct iio_dev *indio_dev, - uintptr_t private, - const struct iio_chan_spec *chan, - char *buf) -{ - struct pac1921_priv *priv =3D iio_priv(indio_dev); - const int (*scales_tbl)[2]; - size_t size; - - switch (chan->channel) { - case PAC1921_CHAN_VBUS: - scales_tbl =3D pac1921_vbus_scales; - size =3D ARRAY_SIZE(pac1921_vbus_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - - case PAC1921_CHAN_VSENSE: - scales_tbl =3D pac1921_vsense_scales; - size =3D ARRAY_SIZE(pac1921_vsense_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - - case PAC1921_CHAN_CURRENT: { - guard(mutex)(&priv->lock); - scales_tbl =3D priv->current_scales; - size =3D ARRAY_SIZE(priv->current_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - } - default: - return -EINVAL; - } -} - -#define PAC1921_EXT_INFO_SCALE_AVAIL { \ - .name =3D "scale_available", \ - .read =3D pac1921_read_scale_avail, \ - .shared =3D IIO_SEPARATE, \ -} - -static const struct iio_chan_spec_ext_info pac1921_ext_info_voltage[] =3D { - PAC1921_EXT_INFO_SCALE_AVAIL, - {} -}; - static const struct iio_chan_spec_ext_info pac1921_ext_info_current[] =3D { - PAC1921_EXT_INFO_SCALE_AVAIL, { .name =3D "shunt_resistor", .read =3D pac1921_read_shunt_resistor, @@ -910,6 +871,7 @@ static const struct iio_chan_spec pac1921_channels[] = =3D { .type =3D IIO_VOLTAGE, .info_mask_separate =3D BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available =3D BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all =3D BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -927,12 +889,12 @@ static const struct iio_chan_spec pac1921_channels[] = =3D { .indexed =3D 1, .event_spec =3D pac1921_overflow_event, .num_event_specs =3D ARRAY_SIZE(pac1921_overflow_event), - .ext_info =3D pac1921_ext_info_voltage, }, { .type =3D IIO_VOLTAGE, .info_mask_separate =3D BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available =3D BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all =3D BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -950,12 +912,12 @@ static const struct iio_chan_spec pac1921_channels[] = =3D { .indexed =3D 1, .event_spec =3D pac1921_overflow_event, .num_event_specs =3D ARRAY_SIZE(pac1921_overflow_event), - .ext_info =3D pac1921_ext_info_voltage, }, { .type =3D IIO_CURRENT, .info_mask_separate =3D BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available =3D BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all =3D BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ), --=20 2.47.0 From nobody Tue Nov 26 04:35:46 2024 Received: from mail-wr1-f43.google.com (mail-wr1-f43.google.com [209.85.221.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1FD831F76C1; 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[82.56.18.47]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4316f570d86sm58173265e9.8.2024.10.21.05.56.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2024 05:56:28 -0700 (PDT) From: Matteo Martelli Date: Mon, 21 Oct 2024 14:54:17 +0200 Subject: [PATCH v5 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: <20241021-iio-read-avail-release-v5-4-b168713fab33@gmail.com> References: <20241021-iio-read-avail-release-v5-0-b168713fab33@gmail.com> In-Reply-To: <20241021-iio-read-avail-release-v5-0-b168713fab33@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, }; 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[82.56.18.47]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-37ee0b9cd48sm4275204f8f.111.2024.10.21.05.56.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2024 05:56:30 -0700 (PDT) From: Matteo Martelli Date: Mon, 21 Oct 2024 14:54:18 +0200 Subject: [PATCH v5 5/5] iio: as73211: copy/release available integration times 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: <20241021-iio-read-avail-release-v5-5-b168713fab33@gmail.com> References: <20241021-iio-read-avail-release-v5-0-b168713fab33@gmail.com> In-Reply-To: <20241021-iio-read-avail-release-v5-0-b168713fab33@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 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. Tested-by: Christian Eggers Signed-off-by: Matteo Martelli --- drivers/iio/light/as73211.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/iio/light/as73211.c b/drivers/iio/light/as73211.c index be0068081ebbbb37fdfb252b67a77b302ff725f6..c4c94873e6a1cc926cfb724d906= b07222773c43f 100644 --- a/drivers/iio/light/as73211.c +++ b/drivers/iio/light/as73211.c @@ -108,7 +108,8 @@ struct as73211_spec_dev_data { * @creg1: Cached Configuration Register 1. * @creg2: Cached Configuration Register 2. * @creg3: Cached Configuration Register 3. - * @mutex: Keeps cached registers in sync with the device. + * @mutex: Keeps cached registers in sync with the device and protects + * int_time_avail concurrent access for updating and reading. * @completion: Completion to wait for interrupt. * @int_time_avail: Available integration times (depend on sampling freque= ncy). * @spec_dev: device-specific configuration. @@ -493,17 +494,32 @@ static int as73211_read_avail(struct iio_dev *indio_d= ev, 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 +715,7 @@ static irqreturn_t as73211_trigger_handler(int irq __al= ways_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 2.47.0