This is a note to let you know that I've just added the patch titled
iio: addac: ad74413r: fix integer promotion bug in ad74413_get_input_current_offset()
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iio-addac-ad74413r-fix-integer-promotion-bug-in-ad74413_get_input_current_offset.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 980389d06d08442fad0139874bff455c76125e47 Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Date: Fri, 18 Nov 2022 13:32:08 +0100
Subject: iio: addac: ad74413r: fix integer promotion bug in ad74413_get_input_current_offset()
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From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
commit 980389d06d08442fad0139874bff455c76125e47 upstream.
The constant AD74413R_ADC_RESULT_MAX is defined via GENMASK, so its
type is "unsigned long".
Hence in the expression voltage_offset * AD74413R_ADC_RESULT_MAX,
voltage_offset is first promoted to unsigned long, and since it may be
negative, that results in a garbage value. For example, when range is
AD74413R_ADC_RANGE_5V_BI_DIR, voltage_offset is -2500 and
voltage_range is 5000, so the RHS of this assignment is, depending on
sizeof(long), either 826225UL or 3689348814709142UL, which after
truncation to int then results in either 826225 or 1972216214 being
the output from in_currentX_offset.
Casting to int avoids that promotion and results in the correct -32767
output.
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Fixes: fea251b6a5db (iio: addac: add AD74413R driver)
Reviewed-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221118123209.1658420-1-linux@xxxxxxxxxxxxxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iio/addac/ad74413r.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/iio/addac/ad74413r.c
+++ b/drivers/iio/addac/ad74413r.c
@@ -691,7 +691,7 @@ static int ad74413_get_input_current_off
if (ret)
return ret;
- *val = voltage_offset * AD74413R_ADC_RESULT_MAX / voltage_range;
+ *val = voltage_offset * (int)AD74413R_ADC_RESULT_MAX / voltage_range;
return IIO_VAL_INT;
}
Patches currently in stable-queue which might be from linux@xxxxxxxxxxxxxxxxxx are
queue-6.1/iio-addac-ad74413r-fix-integer-promotion-bug-in-ad74413_get_input_current_offset.patch
queue-6.1/iio-adc128s052-add-proper-.data-members-in-adc128_of_match-table.patch
