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Date:   Thu, 17 Feb 2022 12:05:58 +0000 (GMT)
From:   "Maciej W. Rozycki" <macro@orcam.me.uk>
To:     Dan Carpenter <dan.carpenter@oracle.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc:     kbuild@lists.01.org, Jiri Slaby <jirislaby@kernel.org>,
        lkp@intel.com, kbuild-all@lists.01.org,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Mike Skoog <mskoog@endruntechnologies.com>,
        Mike Korreng <mkorreng@endruntechnologies.com>,
        info@endruntechnologies.com, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/2] serial: 8250: Add proper clock handling for OxSemi
 PCIe devices
In-Reply-To: <202202130027.ZKBCgtm5-lkp@intel.com>
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References: <202202130027.ZKBCgtm5-lkp@intel.com>
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On Thu, 17 Feb 2022, Dan Carpenter wrote:

> url:    https://github.com/0day-ci/linux/commits/Maciej-W-Rozycki/serial-8250-Fixes-for-Oxford-Semiconductor-950-UARTs/20220212-164255
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
> config: x86_64-randconfig-m001 (https://download.01.org/0day-ci/archive/20220213/202202130027.ZKBCgtm5-lkp@intel.com/config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> New smatch warnings:
> drivers/tty/serial/8250/8250_pci.c:1171 pci_oxsemi_tornado_get_divisor() error: uninitialized symbol 'tcr'.
> drivers/tty/serial/8250/8250_pci.c:1172 pci_oxsemi_tornado_get_divisor() error: uninitialized symbol 'quot'.
> drivers/tty/serial/8250/8250_pci.c:1180 pci_oxsemi_tornado_get_divisor() error: uninitialized symbol 'cpr'.

 These variables do get assigned to in the first iteration of the loop, 
because the deviation calculated (`srem') is normalised to the range of 
[0,spre/2] and that divided by the original divisor (`spre') always works 
out at within [0,0.5], so `squot' will be within [0,32768].  I guess the 
static analyser is too dumb to figure it out, so I'll see how to paper it 
over unless someone has a better proposal.

 Greg: shall I send an update patch or a replacement v4 of the series?

  Maciej