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Message-ID: <02c0b221-9d4e-43fd-9dc8-40827698e947@mev.co.uk>
Date: Thu, 18 Jan 2024 15:23:50 +0000
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Subject: Re: [PATCH] comedi: drivers: ni_tio: Fix arithmetic expression
 overflow
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To: David Laight <David.Laight@ACULAB.COM>,
 'Greg Kroah-Hartman' <gregkh@linuxfoundation.org>,
 Denis Arefev <arefev@swemel.ru>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 "lvc-project@linuxtesting.org" <lvc-project@linuxtesting.org>,
 "stable@vger.kernel.org" <stable@vger.kernel.org>
References: <20240118123747.45795-1-arefev@swemel.ru>
 <2024011842-groggy-badly-393c@gregkh>
 <3f8d1a69e3434d2085aa3564357fa31d@AcuMS.aculab.com>
From: Ian Abbott <abbotti@mev.co.uk>
Organization: MEV Ltd.
In-Reply-To: <3f8d1a69e3434d2085aa3564357fa31d@AcuMS.aculab.com>
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On 2024-01-18 14:37, David Laight wrote:
>> -----Original Message-----
>> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Sent: 18 January 2024 14:14
>> To: Denis Arefev <arefev@swemel.ru>
>> Cc: Ian Abbott <abbotti@mev.co.uk>; H Hartley Sweeten <hsweeten@visionengravers.com>; linux-
>> kernel@vger.kernel.org; lvc-project@linuxtesting.org; stable@vger.kernel.org
>> Subject: Re: [PATCH] comedi: drivers: ni_tio: Fix arithmetic expression overflow
>>
>> On Thu, Jan 18, 2024 at 03:37:47PM +0300, Denis Arefev wrote:
>>> The value of an arithmetic expression period_ns * 1000 is subject
>>> to overflow due to a failure to cast operands to a larger data
>>> type before performing arithmetic
>>>
>>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>>
>>> Fixes: 3e90b1c7ebe9 ("staging: comedi: ni_tio: tidy up ni_tio_set_clock_src() and helpers")
>>> Cc: <stable@vger.kernel.org> # v5.15+
>>> Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
>>> Signed-off-by: Denis Arefev <arefev@swemel.ru>
>>> Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
>>> ---
>>>   drivers/comedi/drivers/ni_tio.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/comedi/drivers/ni_tio.c b/drivers/comedi/drivers/ni_tio.c
>>> index da6826d77e60..acc914903c70 100644
>>> --- a/drivers/comedi/drivers/ni_tio.c
>>> +++ b/drivers/comedi/drivers/ni_tio.c
>>> @@ -800,7 +800,7 @@ static int ni_tio_set_clock_src(struct ni_gpct *counter,
>>>   				GI_PRESCALE_X2(counter_dev->variant) |
>>>   				GI_PRESCALE_X8(counter_dev->variant), bits);
>>>   	}
>>> -	counter->clock_period_ps = period_ns * 1000;
>>> +	counter->clock_period_ps = period_ns * 1000UL;
> 
> What about 32bit systems...

Oh, good point.  It should be 1000ULL.

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