drivers/char/xillybus/xillybus_class.c:230 xillybus_find_inode() warn: variable dereferenced before check 'inode' (see line 226)

BCC: [email protected]
CC: [email protected]
TO: Eli Billauer <[email protected]>
CC: 0day robot <[email protected]>

tree:   https://github.com/intel-lab-lkp/linux/commits/Eli-Billauer/char-xillybus-Improve-control-of-execution-flow-with-mutexes/20260806-033404
head:   d05c024c9354aabd2ea64be46e6fccbf24ba33cd
commit: 16edb90c39a5645b3803be32b2b77476efae2402 char: xillybus: Add defensive sanity checks
date:   2 days ago
:::::: branch date: 2 days ago
:::::: commit date: 2 days ago
config: i386-randconfig-141 (https://download.01.org/0day-ci/archive/20260807/[email protected]/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
smatch: v0.5.0-9187-g5189e3fb

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 <[email protected]>
| Reported-by: Dan Carpenter <[email protected]>
| Closes: https://lore.kernel.org/r/[email protected]/

smatch warnings:
drivers/char/xillybus/xillybus_class.c:230 xillybus_find_inode() warn: variable dereferenced before check 'inode' (see line 226)

vim +/inode +230 drivers/char/xillybus/xillybus_class.c

8cb5d216ab3365 Eli Billauer  2021-05-26  222  
8cb5d216ab3365 Eli Billauer  2021-05-26  223  int xillybus_find_inode(struct inode *inode,
8cb5d216ab3365 Eli Billauer  2021-05-26  224  			void **private_data, int *index)
8cb5d216ab3365 Eli Billauer  2021-05-26  225  {
8cb5d216ab3365 Eli Billauer  2021-05-26 @226  	int minor = iminor(inode);
8cb5d216ab3365 Eli Billauer  2021-05-26  227  	int major = imajor(inode);
4834f9898c7301 Jakob Koschel 2022-03-24  228  	struct xilly_unit *unit = NULL, *iter;
8cb5d216ab3365 Eli Billauer  2021-05-26  229  
16edb90c39a564 Eli Billauer  2026-06-30 @230  	if (!inode || !private_data || !index)
16edb90c39a564 Eli Billauer  2026-06-30  231  		return -ENODEV;
16edb90c39a564 Eli Billauer  2026-06-30  232  
8cb5d216ab3365 Eli Billauer  2021-05-26  233  	mutex_lock(&unit_mutex);
8cb5d216ab3365 Eli Billauer  2021-05-26  234  
4834f9898c7301 Jakob Koschel 2022-03-24  235  	list_for_each_entry(iter, &unit_list, list_entry)
4834f9898c7301 Jakob Koschel 2022-03-24  236  		if (iter->major == major &&
4834f9898c7301 Jakob Koschel 2022-03-24  237  		    minor >= iter->lowest_minor &&
4834f9898c7301 Jakob Koschel 2022-03-24  238  		    minor < (iter->lowest_minor + iter->num_nodes)) {
4834f9898c7301 Jakob Koschel 2022-03-24  239  			unit = iter;
8cb5d216ab3365 Eli Billauer  2021-05-26  240  			break;
8cb5d216ab3365 Eli Billauer  2021-05-26  241  		}
8cb5d216ab3365 Eli Billauer  2021-05-26  242  
c002f04c0bc79e Eli Billauer  2022-11-17  243  	if (!unit) {
8cb5d216ab3365 Eli Billauer  2021-05-26  244  		mutex_unlock(&unit_mutex);
8cb5d216ab3365 Eli Billauer  2021-05-26  245  		return -ENODEV;
c002f04c0bc79e Eli Billauer  2022-11-17  246  	}
8cb5d216ab3365 Eli Billauer  2021-05-26  247  
8cb5d216ab3365 Eli Billauer  2021-05-26  248  	*private_data = unit->private_data;
8cb5d216ab3365 Eli Billauer  2021-05-26  249  	*index = minor - unit->lowest_minor;
8cb5d216ab3365 Eli Billauer  2021-05-26  250  
c002f04c0bc79e Eli Billauer  2022-11-17  251  	mutex_unlock(&unit_mutex);
8cb5d216ab3365 Eli Billauer  2021-05-26  252  	return 0;
8cb5d216ab3365 Eli Billauer  2021-05-26  253  }
8cb5d216ab3365 Eli Billauer  2021-05-26  254  EXPORT_SYMBOL(xillybus_find_inode);
8cb5d216ab3365 Eli Billauer  2021-05-26  255  

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