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From: kernel test robot <lkp@intel.com>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: clang-built-linux@googlegroups.com, kbuild-all@lists.01.org,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	linux-kernel@vger.kernel.org
Subject: [djwong-xfs:dax-zeroinit-clear-poison-5.15 68/68] fs/ext4/extents.c:4695:8: warning: variable 'max_blocks' is used uninitialized whenever 'if' condition is true
Date: Tue, 17 Aug 2021 10:37:55 +0800	[thread overview]
Message-ID: <202108171047.0SC2CAbq-lkp@intel.com> (raw)

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git dax-zeroinit-clear-poison-5.15
head:   6380ce8db23c88d70b9954ff66477719ea84bf3f
commit: 6380ce8db23c88d70b9954ff66477719ea84bf3f [68/68] ext4: use DAX block device zeroout for FSDAX file ZERO_RANGE operations
config: x86_64-randconfig-a011-20210816 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 44d0a99a12ec7ead4d2f5ef649ba05b40f6d463d)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/commit/?id=6380ce8db23c88d70b9954ff66477719ea84bf3f
        git remote add djwong-xfs https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git
        git fetch --no-tags djwong-xfs dax-zeroinit-clear-poison-5.15
        git checkout 6380ce8db23c88d70b9954ff66477719ea84bf3f
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> fs/ext4/extents.c:4695:8: warning: variable 'max_blocks' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
                           if (ret || did_zeroout)
                               ^~~~~~~~~~~~~~~~~~
   fs/ext4/extents.c:4741:43: note: uninitialized use occurs here
           trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
                                                    ^~~~~~~~~~
   fs/ext4/extents.c:4695:4: note: remove the 'if' if its condition is always false
                           if (ret || did_zeroout)
                           ^~~~~~~~~~~~~~~~~~~~~~~
>> fs/ext4/extents.c:4695:8: warning: variable 'max_blocks' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
                           if (ret || did_zeroout)
                               ^~~
   fs/ext4/extents.c:4741:43: note: uninitialized use occurs here
           trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
                                                    ^~~~~~~~~~
   fs/ext4/extents.c:4695:8: note: remove the '||' if its condition is always false
                           if (ret || did_zeroout)
                               ^~~~~~
   fs/ext4/extents.c:4638:25: note: initialize the variable 'max_blocks' to silence this warning
           unsigned int max_blocks;
                                  ^
                                   = 0
   2 warnings generated.


vim +4695 fs/ext4/extents.c

  4626	
  4627	/*
  4628	 * preallocate space for a file. This implements ext4's fallocate file
  4629	 * operation, which gets called from sys_fallocate system call.
  4630	 * For block-mapped files, posix_fallocate should fall back to the method
  4631	 * of writing zeroes to the required new blocks (the same behavior which is
  4632	 * expected for file systems which do not support fallocate() system call).
  4633	 */
  4634	long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
  4635	{
  4636		struct inode *inode = file_inode(file);
  4637		loff_t new_size = 0;
  4638		unsigned int max_blocks;
  4639		int ret = 0;
  4640		int flags;
  4641		ext4_lblk_t lblk;
  4642		unsigned int blkbits = inode->i_blkbits;
  4643	
  4644		/*
  4645		 * Encrypted inodes can't handle collapse range or insert
  4646		 * range since we would need to re-encrypt blocks with a
  4647		 * different IV or XTS tweak (which are based on the logical
  4648		 * block number).
  4649		 */
  4650		if (IS_ENCRYPTED(inode) &&
  4651		    (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
  4652			return -EOPNOTSUPP;
  4653	
  4654		/* Return error if mode is not supported */
  4655		if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
  4656			     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
  4657			     FALLOC_FL_INSERT_RANGE))
  4658			return -EOPNOTSUPP;
  4659	
  4660		ext4_fc_start_update(inode);
  4661	
  4662		if (mode & FALLOC_FL_PUNCH_HOLE) {
  4663			ret = ext4_punch_hole(inode, offset, len);
  4664			goto exit;
  4665		}
  4666	
  4667		ret = ext4_convert_inline_data(inode);
  4668		if (ret)
  4669			goto exit;
  4670	
  4671		if (mode & FALLOC_FL_COLLAPSE_RANGE) {
  4672			ret = ext4_collapse_range(inode, offset, len);
  4673			goto exit;
  4674		}
  4675	
  4676		if (mode & FALLOC_FL_INSERT_RANGE) {
  4677			ret = ext4_insert_range(inode, offset, len);
  4678			goto exit;
  4679		}
  4680	
  4681		if (mode & FALLOC_FL_ZERO_RANGE) {
  4682			/*
  4683			 * If the file is in DAX mode, try to use a DAX-specific
  4684			 * function to zero the region.
  4685			 */
  4686			if (IS_DAX(inode)) {
  4687				bool	did_zeroout = false;
  4688	
  4689				inode_lock(inode);
  4690	
  4691				ret = dax_zeroinit_range(inode, offset, len,
  4692						&did_zeroout, &ext4_iomap_report_ops);
  4693				if (ret == -EINVAL)
  4694					ret = 0;
> 4695				if (ret || did_zeroout)
  4696					goto out;
  4697	
  4698				inode_unlock(inode);
  4699			}
  4700			ret = ext4_zero_range(file, offset, len, mode);
  4701			goto exit;
  4702		}
  4703		trace_ext4_fallocate_enter(inode, offset, len, mode);
  4704		lblk = offset >> blkbits;
  4705	
  4706		max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
  4707		flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
  4708	
  4709		inode_lock(inode);
  4710	
  4711		/*
  4712		 * We only support preallocation for extent-based files only
  4713		 */
  4714		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
  4715			ret = -EOPNOTSUPP;
  4716			goto out;
  4717		}
  4718	
  4719		if (!(mode & FALLOC_FL_KEEP_SIZE) &&
  4720		    (offset + len > inode->i_size ||
  4721		     offset + len > EXT4_I(inode)->i_disksize)) {
  4722			new_size = offset + len;
  4723			ret = inode_newsize_ok(inode, new_size);
  4724			if (ret)
  4725				goto out;
  4726		}
  4727	
  4728		/* Wait all existing dio workers, newcomers will block on i_mutex */
  4729		inode_dio_wait(inode);
  4730	
  4731		ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
  4732		if (ret)
  4733			goto out;
  4734	
  4735		if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
  4736			ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
  4737						EXT4_I(inode)->i_sync_tid);
  4738		}
  4739	out:
  4740		inode_unlock(inode);
  4741		trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
  4742	exit:
  4743		ext4_fc_stop_update(inode);
  4744		return ret;
  4745	}
  4746	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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                 reply	other threads:[~2021-08-17  2:38 UTC|newest]

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