Messages in this thread | | | Date | Tue, 31 Jul 2012 14:42:37 +0200 | From | Lars-Peter Clausen <> | Subject | Re: NULL pointer dereference in iio_buffer_register() |
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On 07/31/2012 12:31 PM, Fengguang Wu wrote: >> [ 7.623739] BUG: unable to handle kernel NULL pointer dereference at 00000000000000b0 > > I managed to root cause it: > > [ 2.108085] BUG: unable to handle kernel NULL pointer dereference at 00000060 > [ 2.112015] EIP: [<c19b4f4f>] iio_buffer_register+0x1f/0x360 SS:ESP 0068:ce837f34 > > $ addr2line -e vmlinux -i c19b4f4f > /c/wfg/linux/drivers/iio/industrialio-buffer.c:275 > > (gdb) p &((struct iio_buffer *) 0)->attrs > $1 = (const struct attribute_group **) 0x60 > > The panic happens while trying to dereference the NULL indio_dev->buffer: > > 266 int iio_buffer_register(struct iio_dev *indio_dev, > 267 const struct iio_chan_spec *channels, > 268 int num_channels) > 269 { > 270 struct iio_dev_attr *p; > 271 struct attribute **attr; > 272 struct iio_buffer *buffer = indio_dev->buffer; > 273 int ret, i, attrn, attrcount, attrcount_orig = 0; > 274 > ==> 275 if (buffer->attrs) > 276 indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs; > > iio_dummy_probe() has the code to configure that buffer, however > iio_simple_dummy_configure_buffer() is defined to do nothing on > !CONFIG_IIO_SIMPLE_DUMMY_BUFFER.. > > 448 /* Configure buffered capture support. */ > ==> 449 ret = iio_simple_dummy_configure_buffer(indio_dev); > 450 if (ret < 0) > 451 goto error_unregister_events; > 452 > 453 /* > 454 * Register the channels with the buffer, but avoid the output > 455 * channel being registered by reducing the number of channels by 1. > 456 */ > 457 ret = iio_buffer_register(indio_dev, iio_dummy_channels, 5); > 458 if (ret < 0) > 459 goto error_unconfigure_buffer; > > Any ideas to fix it? >
Hi,
I think the best would be to move the iio_buffer_register to iio_simple_dummy_configure_buffer.
- Lars
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