Re: [PATCH v2 1/2] serial: 8250_pci: Replace custom pci_match_id() implementation

From: kernel test robot <lkp@intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>
Subject: Re: [PATCH v2 1/2] serial: 8250_pci: Replace custom pci_match_id() implementation
Date: Tue, 26 Oct 2021 20:45:48 +0800	[thread overview]
Message-ID: <202110262029.9bqOz12y-lkp@intel.com> (raw)
In-Reply-To: <20211025124533.29977-1-andriy.shevchenko@linux.intel.com>

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Hi Andy,

I love your patch! Perhaps something to improve:

[auto build test WARNING on tty/tty-testing]
[cannot apply to v5.15-rc7 next-20211026]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Andy-Shevchenko/serial-8250_pci-Replace-custom-pci_match_id-implementation/20211025-204752
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
config: i386-randconfig-a003-20211025 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project a461fa64bb37cffd73f683c74f6b0780379fc2ca)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/24a32531ba63f472ec6f40c4d431cb5369b29818
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Andy-Shevchenko/serial-8250_pci-Replace-custom-pci_match_id-implementation/20211025-204752
        git checkout 24a32531ba63f472ec6f40c4d431cb5369b29818
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/tty/serial/8250/8250_pci.c:1268:6: warning: variable 'amcc' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (match)
               ^~~~~
   drivers/tty/serial/8250/8250_pci.c:1273:6: note: uninitialized use occurs here
           if (amcc) {
               ^~~~
   drivers/tty/serial/8250/8250_pci.c:1268:2: note: remove the 'if' if its condition is always true
           if (match)
           ^~~~~~~~~~
   drivers/tty/serial/8250/8250_pci.c:1265:11: note: initialize the variable 'amcc' to silence this warning
           bool amcc;
                    ^
                     = 0
   1 warning generated.

vim +1268 drivers/tty/serial/8250/8250_pci.c

  1261	
  1262	static int pci_quatech_init(struct pci_dev *dev)
  1263	{
  1264		const struct pci_device_id *match;
  1265		bool amcc;
  1266	
  1267		match = pci_match_id(quatech_cards, dev);
> 1268		if (match)
  1269			amcc = match->driver_data;
  1270		else
  1271			pci_err(dev, "unknown port type '0x%04X'.\n", dev->device);
  1272	
  1273		if (amcc) {
  1274			unsigned long base = pci_resource_start(dev, 0);
  1275			if (base) {
  1276				u32 tmp;
  1277	
  1278				outl(inl(base + 0x38) | 0x00002000, base + 0x38);
  1279				tmp = inl(base + 0x3c);
  1280				outl(tmp | 0x01000000, base + 0x3c);
  1281				outl(tmp &= ~0x01000000, base + 0x3c);
  1282			}
  1283		}
  1284		return 0;
  1285	}
  1286	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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