linux-kernel - [dhowells-fs:fscache-rewrite-indexing 78/80] fs/cachefiles/namei.c:403:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true

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Message-ID: <202110130328.qtDEBsJF-lkp@intel.com>
Date:   Wed, 13 Oct 2021 03:35:35 +0800
From:   kernel test robot <lkp@...el.com>
To:     David Howells <dhowells@...hat.com>
Cc:     llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
        linux-kernel@...r.kernel.org
Subject: [dhowells-fs:fscache-rewrite-indexing 78/80]
 fs/cachefiles/namei.c:403:6: warning: variable 'ret' is used uninitialized
 whenever 'if' condition is true

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git fscache-rewrite-indexing
head:   5914ee72cd59ac43f27adae6340e8219592462d5
commit: b91996136a2f21b2815b8946274abe7064a7dceb [78/80] cachefiles: Don't set object->file until after open is successful
config: x86_64-randconfig-a015-20211012 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c3dcf39554dbea780d6cb7e12239451ba47a2668)
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/dhowells/linux-fs.git/commit/?id=b91996136a2f21b2815b8946274abe7064a7dceb
        git remote add dhowells-fs https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
        git fetch --no-tags dhowells-fs fscache-rewrite-indexing
        git checkout b91996136a2f21b2815b8946274abe7064a7dceb
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=x86_64 

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

All warnings (new ones prefixed by >>):

>> fs/cachefiles/namei.c:403:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (!cachefiles_open_file(object, dentry))
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/cachefiles/namei.c:412:6: note: uninitialized use occurs here
           if (ret == -EIO)
               ^~~
   fs/cachefiles/namei.c:403:2: note: remove the 'if' if its condition is always false
           if (!cachefiles_open_file(object, dentry))
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/cachefiles/namei.c:378:9: note: initialize the variable 'ret' to silence this warning
           int ret;
                  ^
                   = 0
   1 warning generated.


vim +403 fs/cachefiles/namei.c

   369	
   370	/*
   371	 * walk from the parent object to the child object through the backing
   372	 * filesystem, creating directories as we go
   373	 */
   374	bool cachefiles_look_up_object(struct cachefiles_object *object)
   375	{
   376		struct cachefiles_volume *volume = object->volume;
   377		struct dentry *dentry, *fan = volume->fanout[(u8)object->key_hash];
   378		int ret;
   379	
   380		_enter("OBJ%x,%s,", object->debug_id, object->d_name);
   381	
   382		/* Look up path "cache/vol/fanout/file". */
   383		dentry = lookup_positive_unlocked(object->d_name, fan, object->d_name_len);
   384		trace_cachefiles_lookup(object, dentry);
   385		if (IS_ERR(dentry)) {
   386			if (dentry == ERR_PTR(-ENOENT))
   387				goto new_file;
   388			ret = PTR_ERR(dentry);
   389			goto lookup_error;
   390		}
   391	
   392		if (!d_is_reg(dentry)) {
   393			pr_err("%pd is not a file\n", dentry);
   394			inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
   395			ret = cachefiles_bury_object(volume->cache, object, fan, dentry,
   396						     FSCACHE_OBJECT_IS_WEIRD);
   397			dput(dentry);
   398			if (ret < 0)
   399				return false;
   400			goto new_file;
   401		}
   402	
 > 403		if (!cachefiles_open_file(object, dentry))
   404			goto lookup_error;
   405	
   406		_leave(" = t [%lu]", file_inode(object->file)->i_ino);
   407		return true;
   408	
   409	new_file:
   410		return cachefiles_create_file(object);
   411	lookup_error:
   412		if (ret == -EIO)
   413			cachefiles_io_error_obj(object, "Lookup failed");
   414		return false;
   415	}
   416	

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

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