[amir73il:ovl_copy_file_range 3/6] fs/read_write.c:1499 copy_file_fs_cmp() error: we previously assumed 'f_out->f_op' could be null (see line 1496)

BCC: [email protected]
CC: [email protected]
TO: Amir Goldstein <[email protected]>

tree:   https://github.com/amir73il/linux ovl_copy_file_range
head:   4421f88f42bb20b8a6f9fd56c5c877a1088d0e00
commit: b86e287575a3f81b04ef92b5bb46f87329fc314f [3/6] fs: add support for copy file range from another fs
:::::: branch date: 9 hours ago
:::::: commit date: 9 hours ago
config: i386-randconfig-141-20260714 (https://download.01.org/0day-ci/archive/20260714/[email protected]/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
smatch: v0.5.0-9185-gbcc58b9c

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]/

New smatch warnings:
fs/read_write.c:1499 copy_file_fs_cmp() error: we previously assumed 'f_out->f_op' could be null (see line 1496)

Old smatch warnings:
fs/read_write.c:1631 vfs_copy_file_range() error: we previously assumed 'file_out->f_op->copy_file_range' could be null (see line 1614)

vim +1499 fs/read_write.c

cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1482  
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1483  /*
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1484   * Check if src and dst file are on the same filesystem.
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1485   * nfs and cifs define several different file_system_type structures
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1486   * and several different sets of file_operations, but they all end up
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1487   * using the same ->copy_file_range() function pointer.
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1488   * COPY_FILE_SPLICE is an opt-in flag for cross-fs copy (e.g. from nfsd),
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1489   * so do not compare src<->dst filesystems in this case.
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1490   */
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1491  static int copy_file_fs_cmp(struct file *f_in, struct file *f_out,
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1492  			    unsigned int flags)
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1493  {
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1494  	if (flags & COPY_FILE_SPLICE)
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1495  		return FS_COPY_SPLICE;
cd6e8d0dbe33ef Amir Goldstein 2026-07-13 @1496  	else if (f_out->f_op && f_out->f_op->copy_file_range &&
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1497  		 f_out->f_op->copy_file_range == f_in->f_op->copy_file_range)
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1498  		return FS_COPY_SAME_FS;
b86e287575a3f8 Amir Goldstein 2026-07-13 @1499  	else if (f_out->f_op->fop_flags & FOP_CROSS_FS_COPY)
b86e287575a3f8 Amir Goldstein 2026-07-13  1500  		return FS_COPY_FROM_OTHER_FS;
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1501  	else if (file_inode(f_in)->i_sb == file_inode(f_out)->i_sb)
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1502  		return FS_COPY_SAME_SB;
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1503  	else
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1504  		return FS_COPY_CROSS_FS;
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1505  }
cd6e8d0dbe33ef Amir Goldstein 2026-07-13  1506  

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