Re: [PATCH 1/2] fat: Add FS_IOC_GETFSLABEL ioctl

[Dan Carpenter <dan.carpenter@linaro.org>]

Hi Ethan,

kernel test robot noticed the following build warnings:

url:    https://github.com/intel-lab-lkp/linux/commits/Ethan-Ferguson/fat-Add-FS_IOC_GETFSLABEL-ioctl/20260211-062606
base:   9f2693489ef8558240d9e80bfad103650daed0af
patch link:    https://lore.kernel.org/r/20260210222310.357755-2-ethan.ferguson%40zetier.com
patch subject: [PATCH 1/2] fat: Add FS_IOC_GETFSLABEL ioctl
config: riscv-randconfig-r071-20260211 (https://download.01.org/0day-ci/archive/20260211/202602111747.QIBXIwpw-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 9.5.0
smatch version: v0.5.0-8994-gd50c5a4c

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 <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202602111747.QIBXIwpw-lkp@intel.com/

smatch warnings:
fs/fat/file.c:160 fat_ioctl_get_volume_label() warn: maybe return -EFAULT instead of the bytes remaining?

vim +160 fs/fat/file.c

5fc1746d68b8fb Ethan Ferguson 2026-02-10  156  static int fat_ioctl_get_volume_label(struct inode *inode, char __user *arg)
5fc1746d68b8fb Ethan Ferguson 2026-02-10  157  {
5fc1746d68b8fb Ethan Ferguson 2026-02-10  158  	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
5fc1746d68b8fb Ethan Ferguson 2026-02-10  159  
5fc1746d68b8fb Ethan Ferguson 2026-02-10 @160  	return copy_to_user(arg, sbi->vol_label, MSDOS_NAME);

This should be:

	if (copy_to_user(arg, sbi->vol_label, MSDOS_NAME))
		return -EFAULT;

	return 0;

5fc1746d68b8fb Ethan Ferguson 2026-02-10  161  }

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