[axboe:rw_iter 115/471] drivers/hid/hid-picolcd_debugfs.c:50 picolcd_debug_reset_write() warn: potential spectre issue 'buf' [w] (local cap)

[kernel test robot <lkp@intel.com>]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Jens Axboe <axboe@kernel.dk>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git rw_iter
head:   0a49759be1c3b29207758e467fdc1a90d0716d06
commit: 7dfd9f363e6d79bc842bf6e7fa86541a21142fef [115/471] drivers/hid: convert to read/write iterators
:::::: branch date: 5 days ago
:::::: commit date: 5 days ago
config: openrisc-randconfig-r071-20260307 (https://download.01.org/0day-ci/archive/20260311/202603111411.GE776lsA-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 15.2.0
smatch: v0.5.0-9004-gb810ac53

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>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202603111411.GE776lsA-lkp@intel.com/

smatch warnings:
drivers/hid/hid-picolcd_debugfs.c:50 picolcd_debug_reset_write() warn: potential spectre issue 'buf' [w] (local cap)

vim +/buf +50 drivers/hid/hid-picolcd_debugfs.c

fabdbf2fd22fa1 Bruno Prémont 2012-07-30  37  
7dfd9f363e6d79 Jens Axboe    2024-04-05  38  static ssize_t picolcd_debug_reset_write(struct kiocb *iocb,
7dfd9f363e6d79 Jens Axboe    2024-04-05  39  					 struct iov_iter *from)
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  40  {
7dfd9f363e6d79 Jens Axboe    2024-04-05  41  	struct picolcd_data *data = ((struct seq_file *)iocb->ki_filp->private_data)->private;
7dfd9f363e6d79 Jens Axboe    2024-04-05  42  	size_t count = iov_iter_count(from);
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  43  	char buf[32];
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  44  	size_t cnt = min(count, sizeof(buf)-1);
7dfd9f363e6d79 Jens Axboe    2024-04-05  45  	if (!copy_from_iter_full(buf, cnt, from))
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  46  		return -EFAULT;
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  47  
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  48  	while (cnt > 0 && (buf[cnt-1] == ' ' || buf[cnt-1] == '\n'))
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  49  		cnt--;
fabdbf2fd22fa1 Bruno Prémont 2012-07-30 @50  	buf[cnt] = '\0';
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  51  	if (strcmp(buf, "all") == 0) {
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  52  		picolcd_reset(data->hdev);
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  53  		picolcd_fb_reset(data, 1);
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  54  	} else if (strcmp(buf, "fb") == 0) {
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  55  		picolcd_fb_reset(data, 1);
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  56  	} else {
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  57  		return -EINVAL;
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  58  	}
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  59  	return count;
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  60  }
fabdbf2fd22fa1 Bruno Prémont 2012-07-30  61  

:::::: The code at line 50 was first introduced by commit
:::::: fabdbf2fd22fa170b4c5340dbdda5c8cd88fb205 HID: picoLCD: split driver code

:::::: TO: Bruno Prémont <bonbons@linux-vserver.org>
:::::: CC: Jiri Kosina <jkosina@suse.cz>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki