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Lars-Peter Clausen authored
commit e1055473 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 959d2952 ("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: 959d2952 ("staging:iio: make iio_sw_buffer_preenable much more general.") Signed-off-by:
Lars-Peter Clausen <lars@metafoo.de> Signed-off-by:
Jonathan Cameron <jic23@kernel.org> Signed-off-by:
Luis Henriques <luis.henriques@canonical.com>
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