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| author | Peter Meerwald <pmeerw@pmeerw.net> | 2013-09-18 22:10:00 +0100 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2013-09-21 12:30:58 +0100 |
| commit | d66e0452bf6b0d98cd1a478918c92f2baffcb413 (patch) | |
| tree | 3773d3ba757b5bc4135db1800355af1d273dc299 | |
| parent | a97dd06948e6ba1ff4fa2e046dd573b4f42a45c1 (diff) | |
| download | blackbird-op-linux-d66e0452bf6b0d98cd1a478918c92f2baffcb413.tar.gz blackbird-op-linux-d66e0452bf6b0d98cd1a478918c92f2baffcb413.zip | |
iio: Fix crash when scan_bytes is computed with active_scan_mask == NULL
if device has available_scan_masks set and the buffer is enabled without
any scan_elements enabled, in a NULL pointer is dereferenced in iio_compute_scan_bytes()
[ 18.993713] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 19.002593] pgd = debd4000
[ 19.005432] [00000000] *pgd=9ebc0831, *pte=00000000, *ppte=00000000
[ 19.012329] Internal error: Oops: 17 [#1] PREEMPT ARM
[ 19.017639] Modules linked in:
[ 19.020843] CPU: 0 Not tainted (3.9.11-00036-g75c888a-dirty #207)
[ 19.027587] PC is at _find_first_bit_le+0xc/0x2c
[ 19.032440] LR is at iio_compute_scan_bytes+0x2c/0xf4
[ 19.037719] pc : [<c021dc60>] lr : [<c03198d0>] psr: 200d0013
[ 19.037719] sp : debd9ed0 ip : 00000000 fp : 000802bc
[ 19.049713] r10: 00000000 r9 : 00000000 r8 : deb67250
[ 19.055206] r7 : 00000000 r6 : 00000000 r5 : 00000000 r4 : deb67000
[ 19.062011] r3 : de96ec00 r2 : 00000000 r1 : 00000004 r0 : 00000000
[ 19.068847] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 19.076324] Control: 10c5387d Table: 9ebd4019 DAC: 00000015
problem is the rollback code in iio_update_buffers(), old_mask may be NULL (e.g. on first
call)
I'm not too confident about the fix; works for me...
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
| -rw-r--r-- | drivers/iio/industrialio-buffer.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index e73033f3839a..5862c88ed5ad 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -528,8 +528,15 @@ int iio_update_buffers(struct iio_dev *indio_dev, * Note can only occur when adding a buffer. */ list_del(&insert_buffer->buffer_list); - indio_dev->active_scan_mask = old_mask; - success = -EINVAL; + if (old_mask) { + indio_dev->active_scan_mask = old_mask; + success = -EINVAL; + } + else { + kfree(compound_mask); + ret = -EINVAL; + goto error_ret; + } } } else { indio_dev->active_scan_mask = compound_mask; |
