From: Lars-Peter Clausen <l...@metafoo.de>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit e10554738cab4224e097c2f9d975ea781a4fcde4 upstream.

In older versions of the IIO framework it was possible to pass a completely
different set of channels to iio_buffer_register() as the one that is
assigned to the IIO device. Commit 959d2952d124 ("staging:iio: make
iio_sw_buffer_preenable much more general.") introduced a restriction that
requires that the set of channels that is passed to iio_buffer_register() is
a subset of the channels assigned to the IIO device as the IIO core will use
the list of channels that is assigned to the device to lookup a channel by
scan index in iio_compute_scan_bytes(). If it can not find the channel the
function will crash. This patch fixes the issue by making sure that the same
set of channels is assigned to the IIO device and passed to
iio_buffer_register().

Note that we need to remove the IIO_CHAN_INFO_RAW and IIO_CHAN_INFO_SCALE
info attributes from the channels since we don't actually want those to be
registered.

Fixes the following crash:
        Unable to handle kernel NULL pointer dereference at virtual address 
00000016
        pgd = d2094000
        [00000016] *pgd=16e39831, *pte=00000000, *ppte=00000000
        Internal error: Oops: 17 [#1] PREEMPT SMP ARM
        Modules linked in:
        CPU: 1 PID: 1695 Comm: bash Not tainted 3.17.0-06329-g29461ee #9686
        task: d7768040 ti: d5bd4000 task.ti: d5bd4000
        PC is at iio_compute_scan_bytes+0x38/0xc0
        LR is at iio_compute_scan_bytes+0x34/0xc0
        pc : [<c0316de8>]    lr : [<c0316de4>]    psr: 60070013
        sp : d5bd5ec0  ip : 00000000  fp : 00000000
        r10: d769f934  r9 : 00000000  r8 : 00000001
        r7 : 00000000  r6 : c8fc6240  r5 : d769f800  r4 : 00000000
        r3 : d769f800  r2 : 00000000  r1 : ffffffff  r0 : 00000000
        Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
        Control: 18c5387d  Table: 1209404a  DAC: 00000015
        Process bash (pid: 1695, stack limit = 0xd5bd4240)
        Stack: (0xd5bd5ec0 to 0xd5bd6000)
        5ec0: d769f800 d7435640 c8fc6240 d769f984 00000000 c03175a4 d7435690 
d7435640
        5ee0: d769f990 00000002 00000000 d769f800 d5bd4000 00000000 000b43a8 
c03177f4
        5f00: d769f810 0162b8c8 00000002 c8fc7e00 d77f1d08 d77f1da8 c8fc7e00 
c01faf1c
        5f20: 00000002 c010694c c010690c d5bd5f88 00000002 c8fc6840 c8fc684c 
c0105e08
        5f40: 00000000 00000000 d20d1580 00000002 000af408 d5bd5f88 c000de84 
c00b76d4
        5f60: d20d1580 000af408 00000002 d20d1580 d20d1580 00000002 000af408 
c000de84
        5f80: 00000000 c00b7a44 00000000 00000000 00000002 b6ebea78 00000002 
000af408
        5fa0: 00000004 c000dd00 b6ebea78 00000002 00000001 000af408 00000002 
00000000
        5fc0: b6ebea78 00000002 000af408 00000004 bee96a4c 000a6094 00000000 
000b43a8
        5fe0: 00000000 bee969cc b6e2eb77 b6e6525c 40070010 00000001 00000000 
00000000
        [<c0316de8>] (iio_compute_scan_bytes) from [<c03175a4>] 
(__iio_update_buffers+0x248/0x438)
        [<c03175a4>] (__iio_update_buffers) from [<c03177f4>] 
(iio_buffer_store_enable+0x60/0x7c)
        [<c03177f4>] (iio_buffer_store_enable) from [<c01faf1c>] 
(dev_attr_store+0x18/0x24)
        [<c01faf1c>] (dev_attr_store) from [<c010694c>] 
(sysfs_kf_write+0x40/0x4c)
        [<c010694c>] (sysfs_kf_write) from [<c0105e08>] 
(kernfs_fop_write+0x110/0x154)
        [<c0105e08>] (kernfs_fop_write) from [<c00b76d4>] (vfs_write+0xbc/0x170)
        [<c00b76d4>] (vfs_write) from [<c00b7a44>] (SyS_write+0x40/0x78)
        [<c00b7a44>] (SyS_write) from [<c000dd00>] (ret_fast_syscall+0x0/0x30)

Fixes: 959d2952d124 ("staging:iio: make iio_sw_buffer_preenable much more 
general.")
Signed-off-by: Lars-Peter Clausen <l...@metafoo.de>
Signed-off-by: Jonathan Cameron <ji...@kernel.org>
Signed-off-by: Jiri Slaby <jsl...@suse.cz>
---
 drivers/staging/iio/meter/ade7758.h      |  1 -
 drivers/staging/iio/meter/ade7758_core.c | 33 ++------------------------------
 drivers/staging/iio/meter/ade7758_ring.c |  3 +--
 3 files changed, 3 insertions(+), 34 deletions(-)

diff --git a/drivers/staging/iio/meter/ade7758.h 
b/drivers/staging/iio/meter/ade7758.h
index 07318203a836..e8c98cf57070 100644
--- a/drivers/staging/iio/meter/ade7758.h
+++ b/drivers/staging/iio/meter/ade7758.h
@@ -119,7 +119,6 @@ struct ade7758_state {
        u8                      *tx;
        u8                      *rx;
        struct mutex            buf_lock;
-       const struct iio_chan_spec *ade7758_ring_channels;
        struct spi_transfer     ring_xfer[4];
        struct spi_message      ring_msg;
        /*
diff --git a/drivers/staging/iio/meter/ade7758_core.c 
b/drivers/staging/iio/meter/ade7758_core.c
index 6005d4aab0c3..6caeb97e75c8 100644
--- a/drivers/staging/iio/meter/ade7758_core.c
+++ b/drivers/staging/iio/meter/ade7758_core.c
@@ -631,8 +631,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 0,
                .extend_name = "raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_A, AD7758_VOLTAGE),
                .scan_index = 0,
                .scan_type = {
@@ -645,8 +643,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 0,
                .extend_name = "raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_A, AD7758_CURRENT),
                .scan_index = 1,
                .scan_type = {
@@ -659,8 +655,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 0,
                .extend_name = "apparent_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_A, AD7758_APP_PWR),
                .scan_index = 2,
                .scan_type = {
@@ -673,8 +667,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 0,
                .extend_name = "active_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_A, AD7758_ACT_PWR),
                .scan_index = 3,
                .scan_type = {
@@ -687,8 +679,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 0,
                .extend_name = "reactive_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_A, AD7758_REACT_PWR),
                .scan_index = 4,
                .scan_type = {
@@ -701,8 +691,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 1,
                .extend_name = "raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_B, AD7758_VOLTAGE),
                .scan_index = 5,
                .scan_type = {
@@ -715,8 +703,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 1,
                .extend_name = "raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_B, AD7758_CURRENT),
                .scan_index = 6,
                .scan_type = {
@@ -729,8 +715,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 1,
                .extend_name = "apparent_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_B, AD7758_APP_PWR),
                .scan_index = 7,
                .scan_type = {
@@ -743,8 +727,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 1,
                .extend_name = "active_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_B, AD7758_ACT_PWR),
                .scan_index = 8,
                .scan_type = {
@@ -757,8 +739,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 1,
                .extend_name = "reactive_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_B, AD7758_REACT_PWR),
                .scan_index = 9,
                .scan_type = {
@@ -771,8 +751,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 2,
                .extend_name = "raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_C, AD7758_VOLTAGE),
                .scan_index = 10,
                .scan_type = {
@@ -785,8 +763,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 2,
                .extend_name = "raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_C, AD7758_CURRENT),
                .scan_index = 11,
                .scan_type = {
@@ -799,8 +775,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 2,
                .extend_name = "apparent_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_C, AD7758_APP_PWR),
                .scan_index = 12,
                .scan_type = {
@@ -813,8 +787,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 2,
                .extend_name = "active_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_C, AD7758_ACT_PWR),
                .scan_index = 13,
                .scan_type = {
@@ -827,8 +799,6 @@ static const struct iio_chan_spec ade7758_channels[] = {
                .indexed = 1,
                .channel = 2,
                .extend_name = "reactive_raw",
-               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .address = AD7758_WT(AD7758_PHASE_C, AD7758_REACT_PWR),
                .scan_index = 14,
                .scan_type = {
@@ -872,13 +842,14 @@ static int ade7758_probe(struct spi_device *spi)
                goto error_free_rx;
        }
        st->us = spi;
-       st->ade7758_ring_channels = &ade7758_channels[0];
        mutex_init(&st->buf_lock);
 
        indio_dev->name = spi->dev.driver->name;
        indio_dev->dev.parent = &spi->dev;
        indio_dev->info = &ade7758_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->channels = ade7758_channels;
+       indio_dev->num_channels = ARRAY_SIZE(ade7758_channels);
 
        ret = ade7758_configure_ring(indio_dev);
        if (ret)
diff --git a/drivers/staging/iio/meter/ade7758_ring.c 
b/drivers/staging/iio/meter/ade7758_ring.c
index 7d5db7175578..6590944a6678 100644
--- a/drivers/staging/iio/meter/ade7758_ring.c
+++ b/drivers/staging/iio/meter/ade7758_ring.c
@@ -89,7 +89,6 @@ static irqreturn_t ade7758_trigger_handler(int irq, void *p)
  **/
 static int ade7758_ring_preenable(struct iio_dev *indio_dev)
 {
-       struct ade7758_state *st = iio_priv(indio_dev);
        unsigned channel;
        int ret;
 
@@ -104,7 +103,7 @@ static int ade7758_ring_preenable(struct iio_dev *indio_dev)
                                 indio_dev->masklength);
 
        ade7758_write_waveform_type(&indio_dev->dev,
-               st->ade7758_ring_channels[channel].address);
+               indio_dev->channels[channel].address);
 
        return 0;
 }
-- 
2.1.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to