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[67.190.64.15]) by smtp.gmail.com with ESMTPSA id s6sm4320356ilk.67.2020.04.13.15.06.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Apr 2020 15:06:38 -0700 (PDT) Date: Mon, 13 Apr 2020 16:06:31 -0600 From: Jeremy Fertic To: Alexandru Ardelean Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, alexandru.tachici@analog.com Subject: Re: [PATCH v3 1/2] iio: adc: ad7192: fix null pointer de-reference crash during probe Message-ID: <20200413220631.GA4884@r2700x.localdomain> References: <20200413082044.81101-1-alexandru.ardelean@analog.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200413082044.81101-1-alexandru.ardelean@analog.com> Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Mon, Apr 13, 2020 at 11:20:43AM +0300, Alexandru Ardelean wrote: > When the 'spi_device_id' table was removed, it omitted to cleanup/fix the > assignment: > 'indio_dev->name = spi_get_device_id(spi)->name;' > > After that patch 'spi_get_device_id(spi)' returns NULL, so this crashes > during probe with null de-ref. > > This change fixes this by introducing an ad7192_chip_info struct, and > defines all part-names [that should be assigned to indio_dev->name] in a > 'ad7192_chip_info_tbl' table. > > With this change, the old 'st->devid' is also moved to be a > 'chip_info->chip_id'. And the old 'ID_AD719X' macros have been renamed to > 'CHIPID_AD719X'. Tld identifiers have been re-purposed to be enum/index > values in the new 'ad7192_chip_info_tbl'. > > This should fix the bug, and maintain the ABI for the 'indio_dev->name' > field. > > Fixes: 66614ab2be38 ("staging: iio: adc: ad7192: removed spi_device_id") > Signed-off-by: Alexandru Ardelean > --- > > Changelog v2 -> v3: > * reworked patch to introduce a chip_info struct for the part-name > * added 2nd patch to move of-table closer to the end of the file; this > patch is more cosmetic; has no fixes tag, but is on top of the previous > > Changelog v1 -> v2: > * fix colon for Fixes tag > * updated commit title a bit; to make it longer > > drivers/iio/adc/ad7192.c | 61 ++++++++++++++++++++++++++++++---------- > 1 file changed, 46 insertions(+), 15 deletions(-) > > diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c > index 8ec28aa8fa8a..7e8662c5cb0e 100644 > --- a/drivers/iio/adc/ad7192.c > +++ b/drivers/iio/adc/ad7192.c > @@ -125,10 +125,10 @@ > #define AD7193_CH_AINCOM 0x600 /* AINCOM - AINCOM */ > > /* ID Register Bit Designations (AD7192_REG_ID) */ > -#define ID_AD7190 0x4 > -#define ID_AD7192 0x0 > -#define ID_AD7193 0x2 > -#define ID_AD7195 0x6 > +#define CHIPID_AD7190 0x4 > +#define CHIPID_AD7192 0x0 > +#define CHIPID_AD7193 0x2 > +#define CHIPID_AD7195 0x6 > #define AD7192_ID_MASK 0x0F > > /* GPOCON Register Bit Designations (AD7192_REG_GPOCON) */ > @@ -161,7 +161,20 @@ enum { > AD7192_SYSCALIB_FULL_SCALE, > }; > > +enum { > + ID_AD7190, > + ID_AD7192, > + ID_AD7193, > + ID_AD7195, > +}; > + > +struct ad7192_chip_info { > + unsigned int chip_id; > + const char *name; > +}; > + > struct ad7192_state { > + const struct ad7192_chip_info *chip_info; > struct regulator *avdd; > struct regulator *dvdd; > struct clk *mclk; > @@ -172,7 +185,6 @@ struct ad7192_state { > u32 conf; > u32 scale_avail[8][2]; > u8 gpocon; > - u8 devid; > u8 clock_sel; > struct mutex lock; /* protect sensor state */ > u8 syscalib_mode[8]; > @@ -348,7 +360,7 @@ static int ad7192_setup(struct ad7192_state *st, struct device_node *np) > > id &= AD7192_ID_MASK; > > - if (id != st->devid) > + if (id != st->chip_info->chip_id) > dev_warn(&st->sd.spi->dev, "device ID query failed (0x%X)\n", > id); > > @@ -363,7 +375,7 @@ static int ad7192_setup(struct ad7192_state *st, struct device_node *np) > st->mode |= AD7192_MODE_REJ60; > > refin2_en = of_property_read_bool(np, "adi,refin2-pins-enable"); > - if (refin2_en && st->devid != ID_AD7195) > + if (refin2_en && st->chip_info->chip_id != CHIPID_AD7195) > st->conf |= AD7192_CONF_REFSEL; > > st->conf &= ~AD7192_CONF_CHOP; > @@ -859,11 +871,30 @@ static const struct iio_chan_spec ad7193_channels[] = { > IIO_CHAN_SOFT_TIMESTAMP(14), > }; > > +static const struct ad7192_chip_info ad7192_chip_info_tbl[] = { > + [ID_AD7190] = { > + .chip_id = CHIPID_AD7190, > + .name = "ad7190", > + }, > + [ID_AD7192] = { > + .chip_id = CHIPID_AD7192, > + .name = "ad7192", > + }, > + [ID_AD7193] = { > + .chip_id = CHIPID_AD7193, > + .name = "ad7193", > + }, > + [ID_AD7195] = { > + .chip_id = CHIPID_AD7195, > + .name = "ad7195", > + }, > +}; > + > static int ad7192_channels_config(struct iio_dev *indio_dev) > { > struct ad7192_state *st = iio_priv(indio_dev); > > - switch (st->devid) { > + switch (st->chip_info->chip_id) { > case ID_AD7193: Would it be better to change this to CHIPID_AD7193? It looks like it works the way you have it, but only by coincidence since it happens to be true that ID_AD7193 == CHIPID_AD7193. Jeremy > indio_dev->channels = ad7193_channels; > indio_dev->num_channels = ARRAY_SIZE(ad7193_channels); > @@ -878,10 +909,10 @@ static int ad7192_channels_config(struct iio_dev *indio_dev) > } > > static const struct of_device_id ad7192_of_match[] = { > - { .compatible = "adi,ad7190", .data = (void *)ID_AD7190 }, > - { .compatible = "adi,ad7192", .data = (void *)ID_AD7192 }, > - { .compatible = "adi,ad7193", .data = (void *)ID_AD7193 }, > - { .compatible = "adi,ad7195", .data = (void *)ID_AD7195 }, > + { .compatible = "adi,ad7190", .data = &ad7192_chip_info_tbl[ID_AD7190] }, > + { .compatible = "adi,ad7192", .data = &ad7192_chip_info_tbl[ID_AD7192] }, > + { .compatible = "adi,ad7193", .data = &ad7192_chip_info_tbl[ID_AD7193] }, > + { .compatible = "adi,ad7195", .data = &ad7192_chip_info_tbl[ID_AD7195] }, > {} > }; > MODULE_DEVICE_TABLE(of, ad7192_of_match); > @@ -938,16 +969,16 @@ static int ad7192_probe(struct spi_device *spi) > } > > spi_set_drvdata(spi, indio_dev); > - st->devid = (unsigned long)of_device_get_match_data(&spi->dev); > + st->chip_info = of_device_get_match_data(&spi->dev); > indio_dev->dev.parent = &spi->dev; > - indio_dev->name = spi_get_device_id(spi)->name; > + indio_dev->name = st->chip_info->name; > indio_dev->modes = INDIO_DIRECT_MODE; > > ret = ad7192_channels_config(indio_dev); > if (ret < 0) > goto error_disable_dvdd; > > - if (st->devid == ID_AD7195) > + if (st->chip_info->chip_id == CHIPID_AD7195) > indio_dev->info = &ad7195_info; > else > indio_dev->info = &ad7192_info; > -- > 2.17.1 >