Re: [PATCH 6/6] drm: zynqmp_dp: Add debugfs interface for compliance testing

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Mon, Mar 18, 2024 at 11:06:40AM -0400, Sean Anderson wrote:
> On 3/16/24 06:14, kernel test robot wrote:
> > Hi Sean,
> > 
> > kernel test robot noticed the following build warnings:
> > 
> > [auto build test WARNING on v6.8]
> > [cannot apply to drm-misc/drm-misc-next linus/master next-20240315]
> > [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#_base_tree_information]
> > 
> > url:    https://github.com/intel-lab-lkp/linux/commits/Sean-Anderson/drm-zynqmp_dp-Downgrade-log-level-for-aux-retries-message/20240316-071208
> > base:   v6.8
> > patch link:    https://lore.kernel.org/r/20240315230916.1759060-7-sean.anderson%40linux.dev
> > patch subject: [PATCH 6/6] drm: zynqmp_dp: Add debugfs interface for compliance testing
> > config: microblaze-allmodconfig (https://download.01.org/0day-ci/archive/20240316/202403161704.ACHJdSJG-lkp@intel.com/config)
> > compiler: microblaze-linux-gcc (GCC) 13.2.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240316/202403161704.ACHJdSJG-lkp@intel.com/reproduce)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202403161704.ACHJdSJG-lkp@intel.com/
> > 
> > All warnings (new ones prefixed by >>):
> > 
> >    drivers/gpu/drm/xlnx/zynqmp_dp.c: In function 'zynqmp_dp_bridge_debugfs_init':
> >>> drivers/gpu/drm/xlnx/zynqmp_dp.c:2168:31: warning: 'sprintf' may write a terminating nul past the end of the destination [-Wformat-overflow=]
> >     2168 |                 sprintf(name, fmt, i);
> >          |                               ^~~
> >    drivers/gpu/drm/xlnx/zynqmp_dp.c:2168:17: note: 'sprintf' output between 18 and 20 bytes into a destination of size 19
> >     2168 |                 sprintf(name, fmt, i);
> >          |                 ^~~~~~~~~~~~~~~~~~~~~
> 
> Not a bug, as i will be at most 4, which uses 1 digit.

The compiler can't know that. Please fix this, there's a zero warning
policy.

> > vim +/sprintf +2168 drivers/gpu/drm/xlnx/zynqmp_dp.c
> > 
> >   2136	
> >   2137	DEFINE_DEBUGFS_ATTRIBUTE(fops_zynqmp_dp_rate, zynqmp_dp_rate_get,
> >   2138				 zynqmp_dp_rate_set, "%llu\n");
> >   2139	
> >   2140	static void zynqmp_dp_bridge_debugfs_init(struct drm_bridge *bridge,
> >   2141						  struct dentry *root)
> >   2142	{
> >   2143		struct zynqmp_dp *dp = bridge_to_dp(bridge);
> >   2144		struct dentry *test;
> >   2145		int i;
> >   2146	
> >   2147		dp->test.bw_code = DP_LINK_BW_5_4;
> >   2148		dp->test.link_cnt = dp->num_lanes;
> >   2149	
> >   2150		test = debugfs_create_dir("test", root);
> >   2151	#define CREATE_FILE(name) \
> >   2152		debugfs_create_file(#name, 0600, test, dp, &fops_zynqmp_dp_##name)
> >   2153		CREATE_FILE(pattern);
> >   2154		CREATE_FILE(enhanced);
> >   2155		CREATE_FILE(downspread);
> >   2156		CREATE_FILE(active);
> >   2157		CREATE_FILE(custom);
> >   2158		CREATE_FILE(rate);
> >   2159		CREATE_FILE(lanes);
> >   2160	
> >   2161		for (i = 0; i < dp->num_lanes; i++) {
> >   2162			static const char fmt[] = "lane%d_preemphasis";
> >   2163			char name[sizeof(fmt)];
> >   2164	
> >   2165			dp->debugfs_train_set[i].dp = dp;
> >   2166			dp->debugfs_train_set[i].lane = i;
> >   2167	
> >> 2168			sprintf(name, fmt, i);
> >   2169			debugfs_create_file(name, 0600, test,
> >   2170					    &dp->debugfs_train_set[i],
> >   2171					    &fops_zynqmp_dp_preemphasis);
> >   2172	
> >   2173			sprintf(name, "lane%d_swing", i);
> >   2174			debugfs_create_file(name, 0600, test,
> >   2175					    &dp->debugfs_train_set[i],
> >   2176					    &fops_zynqmp_dp_swing);
> >   2177		}
> >   2178	}
> >   2179	

-- 
Regards,

Laurent Pinchart