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Subject[PATCH 4.4 54/75] staging: comedi: dmm32at: Fix endian problem for AI command data
Date
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Ian Abbott <abbotti@mev.co.uk>

commit 54999c0d94b3c26625f896f8e3460bc029821578 upstream.

The analog input subdevice supports Comedi asynchronous commands that
use Comedi's 16-bit sample format. However, the call to
`comedi_buf_write_samples()` is passing the address of a 32-bit integer
variable. On bigendian machines, this will copy 2 bytes from the wrong
end of the 32-bit value. Fix it by changing the type of the variable
holding the sample value to `unsigned short`.

[Note: the bug was introduced in commit 1700529b24cc ("staging: comedi:
dmm32at: use comedi_buf_write_samples()") but the patch applies better
to the later (but in the same kernel release) commit 0c0eadadcbe6e
("staging: comedi: dmm32at: introduce dmm32_ai_get_sample()").]

Fixes: 0c0eadadcbe6e ("staging: comedi: dmm32at: introduce dmm32_ai_get_sample()")
Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-7-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/staging/comedi/drivers/dmm32at.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/comedi/drivers/dmm32at.c
+++ b/drivers/staging/comedi/drivers/dmm32at.c
@@ -411,7 +411,7 @@ static irqreturn_t dmm32at_isr(int irq,
{
struct comedi_device *dev = d;
unsigned char intstat;
- unsigned int val;
+ unsigned short val;
int i;

if (!dev->attached) {

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