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[79.18.120.72]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43160e4fe8bsm19734805e9.44.2024.10.18.03.16.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Oct 2024 03:16:57 -0700 (PDT) From: Matteo Martelli Date: Fri, 18 Oct 2024 12:16:41 +0200 Subject: [PATCH v4 2/5] iio: consumers: copy/release available info from producer to fix race Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241018-iio-read-avail-release-v4-2-53c8ac618585@gmail.com> References: <20241018-iio-read-avail-release-v4-0-53c8ac618585@gmail.com> In-Reply-To: <20241018-iio-read-avail-release-v4-0-53c8ac618585@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. Signed-off-by: Matteo Martelli --- drivers/iio/afe/iio-rescale.c | 8 ++++++++ drivers/iio/dac/dpot-dac.c | 8 ++++++++ drivers/iio/inkern.c | 34 ++++++++++++++++++++++++++++------ drivers/iio/multiplexer/iio-mux.c | 8 ++++++++ drivers/power/supply/ingenic-battery.c | 4 +++- include/linux/iio/consumer.h | 4 ++-- 6 files changed, 57 insertions(+), 9 deletions(-) diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 56e5913ab82d1c045c9ca27012008a4495502cbf..78bb86c291706748b4072a484532ad20c415ff9f 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_dev, } } +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 = { .read_raw = rescale_read_raw, .read_avail = rescale_read_avail, + .read_avail_release_resource = rescale_read_avail_release_res, }; 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..43d68e17fc3a5fca59fad6ccf818eeadfecdb8c1 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_dev, return -EINVAL; } +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 = { .read_raw = dpot_dac_read_raw, .read_avail = dpot_dac_read_avail, + .read_avail_release_resource = dpot_dac_read_avail_release_res, .write_raw = dpot_dac_write_raw, }; diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index 7f325b3ed08fae6674245312cf8f57bb151006c0..9af6b33eb8d178ee7b3f5d417ccfa4d0f87835bc 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -760,9 +760,29 @@ static int iio_channel_read_avail(struct iio_channel *chan, if (!iio_channel_has_available(chan->channel, info)) return -EINVAL; - 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 = 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 = 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; } @@ -789,9 +809,11 @@ int iio_read_avail_channel_raw(struct iio_channel *chan, ret = iio_read_avail_channel_attribute(chan, vals, &type, length, IIO_CHAN_INFO_RAW); - if (ret >= 0 && type != IIO_VAL_INT) + if (ret >= 0 && type != IIO_VAL_INT) { /* raw values are assumed to be IIO_VAL_INT */ + kfree(*vals); ret = -EINVAL; + } return ret; } @@ -801,7 +823,7 @@ static int iio_channel_read_max(struct iio_channel *chan, int *val, int *val2, int *type, enum iio_chan_info_enum info) { - const int *vals; + const int *vals __free(kfree) = NULL; int length; int ret; @@ -857,7 +879,7 @@ static int iio_channel_read_min(struct iio_channel *chan, int *val, int *val2, int *type, enum iio_chan_info_enum info) { - const int *vals; + const int *vals __free(kfree) = NULL; int length; int ret; diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c index 2953403bef53bbe47a97a8ab1c475ed88d7f86d2..31345437784b01c5d6f8ea70263f4c2574388e7a 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; } +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 = { .read_raw = mux_read_raw, .read_avail = mux_read_avail, + .read_avail_release_resource = mux_read_avail_release_res, .write_raw = mux_write_raw, }; diff --git a/drivers/power/supply/ingenic-battery.c b/drivers/power/supply/ingenic-battery.c index 0a40f425c27723ccec49985b8b5e14a737b6a7eb..6b7856e69f5fb7b8b73166b9b6825f4af7b19129 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 */ +#include #include #include #include #include #include #include +#include struct ingenic_battery { struct device *dev; @@ -62,7 +64,7 @@ static int ingenic_battery_get_property(struct power_supply *psy, */ static int ingenic_battery_set_scale(struct ingenic_battery *bat) { - const int *scale_raw; + const int *scale_raw __free(kfree) = NULL; int scale_len, scale_type, best_idx = -1, best_mV, max_raw, i, ret; u64 max_mV; diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h index 333d1d8ccb37f387fe531577ac5e0bfc7f752cec..e3e268d2574b3e01c9412449d90d627de7efcd84 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 channel * @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 values * @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.