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From: kernel test robot <lkp@intel.com>
To: kbuild@lists.01.org
Subject: Re: [PATCH v2 15/16] treewide: Remove uninitialized_var() usage
Date: Sat, 20 Jun 2020 20:36:56 +0800	[thread overview]
Message-ID: <202006202000.ehKVf265%lkp@intel.com> (raw)

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CC: kbuild-all(a)lists.01.org
In-Reply-To: <20200620033007.1444705-15-keescook@chromium.org>
References: <20200620033007.1444705-15-keescook@chromium.org>
TO: Kees Cook <keescook@chromium.org>

Hi Kees,

I love your patch! Perhaps something to improve:

[auto build test WARNING on wireless-drivers-next/master]
[also build test WARNING on linus/master v5.8-rc1 next-20200618]
[cannot apply to wireless-drivers/master rw-ubifs/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use  as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Kees-Cook/Remove-uninitialized_var-macro/20200620-113245
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers-next.git master
:::::: branch date: 9 hours ago
:::::: commit date: 9 hours ago
config: i386-randconfig-m021-20200620 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-13) 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>

smatch warnings:
drivers/mtd/nand/raw/nand_ecc.c:357 __nand_calculate_ecc() error: uninitialized symbol 'rp17'.

# https://github.com/0day-ci/linux/commit/f58ed1805d1492d80a38f58702a37a0996973ffc
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout f58ed1805d1492d80a38f58702a37a0996973ffc
vim +/rp17 +357 drivers/mtd/nand/raw/nand_ecc.c

e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  291  
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  292  	/* finally reduce par to 8 bits */
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  293  	par ^= (par >> 8);
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  294  	par &= 0xff;
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  295  
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  296  	/*
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  297  	 * and calculate rp5..rp15..rp17
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  298  	 * note that par = rp4 ^ rp5 and due to the commutative property
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  299  	 * of the ^ operator we can say:
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  300  	 * rp5 = (par ^ rp4);
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  301  	 * The & 0xff seems superfluous, but benchmarking learned that
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  302  	 * leaving it out gives slightly worse results. No idea why, probably
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  303  	 * it has to do with the way the pipeline in pentium is organized.
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  304  	 */
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  305  	rp5 = (par ^ rp4) & 0xff;
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  306  	rp7 = (par ^ rp6) & 0xff;
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  307  	rp9 = (par ^ rp8) & 0xff;
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  308  	rp11 = (par ^ rp10) & 0xff;
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  309  	rp13 = (par ^ rp12) & 0xff;
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  310  	rp15 = (par ^ rp14) & 0xff;
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  311  	if (eccsize_mult == 2)
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  312  		rp17 = (par ^ rp16) & 0xff;
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  313  
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  314  	/*
7854d3f7495b11 drivers/mtd/nand/nand_ecc.c     Brian Norris    2011-06-23  315  	 * Finally calculate the ECC bits.
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  316  	 * Again here it might seem that there are performance optimisations
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  317  	 * possible, but benchmarks showed that on the system this is developed
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  318  	 * the code below is the fastest
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  319  	 */
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  320  	if (sm_order) {
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  321  		code[0] = (invparity[rp7] << 7) | (invparity[rp6] << 6) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  322  			  (invparity[rp5] << 5) | (invparity[rp4] << 4) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  323  			  (invparity[rp3] << 3) | (invparity[rp2] << 2) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  324  			  (invparity[rp1] << 1) | (invparity[rp0]);
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  325  		code[1] = (invparity[rp15] << 7) | (invparity[rp14] << 6) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  326  			  (invparity[rp13] << 5) | (invparity[rp12] << 4) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  327  			  (invparity[rp11] << 3) | (invparity[rp10] << 2) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  328  			  (invparity[rp9] << 1) | (invparity[rp8]);
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  329  	} else {
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  330  		code[1] = (invparity[rp7] << 7) | (invparity[rp6] << 6) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  331  			  (invparity[rp5] << 5) | (invparity[rp4] << 4) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  332  			  (invparity[rp3] << 3) | (invparity[rp2] << 2) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  333  			  (invparity[rp1] << 1) | (invparity[rp0]);
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  334  		code[0] = (invparity[rp15] << 7) | (invparity[rp14] << 6) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  335  			  (invparity[rp13] << 5) | (invparity[rp12] << 4) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  336  			  (invparity[rp11] << 3) | (invparity[rp10] << 2) |
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  337  			  (invparity[rp9] << 1) | (invparity[rp8]);
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  338  	}
309600c14e36d0 drivers/mtd/nand/raw/nand_ecc.c Boris Brezillon 2018-09-04  339  
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  340  	if (eccsize_mult == 1)
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  341  		code[2] =
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  342  		    (invparity[par & 0xf0] << 7) |
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  343  		    (invparity[par & 0x0f] << 6) |
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  344  		    (invparity[par & 0xcc] << 5) |
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  345  		    (invparity[par & 0x33] << 4) |
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  346  		    (invparity[par & 0xaa] << 3) |
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  347  		    (invparity[par & 0x55] << 2) |
e6cf5df1838c28 drivers/mtd/nand/nand_ecc.c     frans           2008-08-15  348  		    3;
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  349  	else
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  350  		code[2] =
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  351  		    (invparity[par & 0xf0] << 7) |
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  352  		    (invparity[par & 0x0f] << 6) |
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  353  		    (invparity[par & 0xcc] << 5) |
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  354  		    (invparity[par & 0x33] << 4) |
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  355  		    (invparity[par & 0xaa] << 3) |
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  356  		    (invparity[par & 0x55] << 2) |
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23 @357  		    (invparity[rp17] << 1) |
d68156cfad0fe0 drivers/mtd/nand/nand_ecc.c     Singh, Vimal    2008-08-23  358  		    (invparity[rp16] << 0);
1c63aca32903ef drivers/mtd/nand/nand_ecc.c     Akinobu Mita    2009-10-22  359  }
1c63aca32903ef drivers/mtd/nand/nand_ecc.c     Akinobu Mita    2009-10-22  360  EXPORT_SYMBOL(__nand_calculate_ecc);
1c63aca32903ef drivers/mtd/nand/nand_ecc.c     Akinobu Mita    2009-10-22  361  

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

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             reply	other threads:[~2020-06-20 12:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-20 12:36 kernel test robot [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-06-20 13:56 [PATCH v2 15/16] treewide: Remove uninitialized_var() usage kernel test robot
2020-06-20  3:29 [PATCH v2 00/16] Remove uninitialized_var() macro Kees Cook
2020-06-20  3:30 ` [PATCH v2 15/16] treewide: Remove uninitialized_var() usage Kees Cook
2020-06-22 11:32   ` Dan Carpenter
2020-06-22 11:32     ` Dan Carpenter

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