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* [amir73il:fsnotify-fixes 2/2] fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
@ 2022-05-09 10:08 ` Dan Carpenter
  0 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2022-05-07 19:26 UTC (permalink / raw)
  To: kbuild

[-- Attachment #1: Type: text/plain, Size: 13823 bytes --]

CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
CC: linux-kernel(a)vger.kernel.org
TO: Amir Goldstein <amir73il@gmail.com>

tree:   https://github.com/amir73il/linux fsnotify-fixes
head:   d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6
commit: d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6 [2/2] fsnotify: send FS_RENAME to groups watching the moved inode
:::::: branch date: 4 hours ago
:::::: commit date: 4 hours ago
config: s390-randconfig-m031-20220508 (https://download.01.org/0day-ci/archive/20220508/202205080346.m0fb3UXK-lkp(a)intel.com/config)
compiler: s390-linux-gcc (GCC) 11.3.0

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

smatch warnings:
fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)

vim +/dir1 +540 fs/notify/fsnotify.c

d9a6f30bb89309 Amir Goldstein          2018-04-20  454  
90586523eb4b34 Eric Paris              2009-05-21  455  /*
40a100d3adc1ad Amir Goldstein          2020-07-22  456   * fsnotify - This is the main call to fsnotify.
40a100d3adc1ad Amir Goldstein          2020-07-22  457   *
40a100d3adc1ad Amir Goldstein          2020-07-22  458   * The VFS calls into hook specific functions in linux/fsnotify.h.
40a100d3adc1ad Amir Goldstein          2020-07-22  459   * Those functions then in turn call here.  Here will call out to all of the
40a100d3adc1ad Amir Goldstein          2020-07-22  460   * registered fsnotify_group.  Those groups can then use the notification event
40a100d3adc1ad Amir Goldstein          2020-07-22  461   * in whatever means they feel necessary.
40a100d3adc1ad Amir Goldstein          2020-07-22  462   *
40a100d3adc1ad Amir Goldstein          2020-07-22  463   * @mask:	event type and flags
40a100d3adc1ad Amir Goldstein          2020-07-22  464   * @data:	object that event happened on
40a100d3adc1ad Amir Goldstein          2020-07-22  465   * @data_type:	type of object for fanotify_data_XXX() accessors
40a100d3adc1ad Amir Goldstein          2020-07-22  466   * @dir:	optional directory associated with event -
40a100d3adc1ad Amir Goldstein          2020-07-22  467   *		if @file_name is not NULL, this is the directory that
40a100d3adc1ad Amir Goldstein          2020-07-22  468   *		@file_name is relative to
40a100d3adc1ad Amir Goldstein          2020-07-22  469   * @file_name:	optional file name associated with event
40a100d3adc1ad Amir Goldstein          2020-07-22  470   * @inode:	optional inode associated with event -
29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  471   *		If @dir and @inode are both non-NULL, event may be
29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  472   *		reported to both.
40a100d3adc1ad Amir Goldstein          2020-07-22  473   * @cookie:	inotify rename cookie
90586523eb4b34 Eric Paris              2009-05-21  474   */
40a100d3adc1ad Amir Goldstein          2020-07-22  475  int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
40a100d3adc1ad Amir Goldstein          2020-07-22  476  	     const struct qstr *file_name, struct inode *inode, u32 cookie)
90586523eb4b34 Eric Paris              2009-05-21  477  {
b54cecf5e2293d Amir Goldstein          2020-06-07  478  	const struct path *path = fsnotify_data_path(data, data_type);
29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  479  	struct super_block *sb = fsnotify_data_sb(data, data_type);
3427ce71554123 Miklos Szeredi          2017-10-30  480  	struct fsnotify_iter_info iter_info = {};
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  481  	struct mount *mnt = NULL;
d25f3ce8da49ce Amir Goldstein          2022-05-07  482  	struct inode *dir1, *dir2;
e54183fa7047c1 Amir Goldstein          2021-11-29  483  	struct dentry *moved;
d25f3ce8da49ce Amir Goldstein          2022-05-07  484  	int dir1_type = 0;
9385a84d7e1f65 Jan Kara                2016-11-10  485  	int ret = 0;
71d734103edfa2 Mel Gorman              2020-07-08  486  	__u32 test_mask, marks_mask;
90586523eb4b34 Eric Paris              2009-05-21  487  
71d734103edfa2 Mel Gorman              2020-07-08  488  	if (path)
aa93bdc5500cc9 Amir Goldstein          2020-03-19  489  		mnt = real_mount(path->mnt);
3a9fb89f4cd04c Eric Paris              2009-12-17  490  
40a100d3adc1ad Amir Goldstein          2020-07-22  491  	if (!inode) {
40a100d3adc1ad Amir Goldstein          2020-07-22  492  		/* Dirent event - report on TYPE_INODE to dir */
40a100d3adc1ad Amir Goldstein          2020-07-22  493  		inode = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07  494  	} else if (mask & FS_RENAME) {
d25f3ce8da49ce Amir Goldstein          2022-05-07  495  		/* For FS_RENAME, dir1 is old_dir and dir2 is new_dir */
e54183fa7047c1 Amir Goldstein          2021-11-29  496  		moved = fsnotify_data_dentry(data, data_type);
d25f3ce8da49ce Amir Goldstein          2022-05-07  497  		dir1 = moved->d_parent->d_inode;
d25f3ce8da49ce Amir Goldstein          2022-05-07  498  		dir2 = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07 @499  		if (dir1->i_fsnotify_marks || dir2->i_fsnotify_marks)
d25f3ce8da49ce Amir Goldstein          2022-05-07  500  			dir1_type = FSNOTIFY_ITER_TYPE_OLD_DIR;
d25f3ce8da49ce Amir Goldstein          2022-05-07  501  		/*
d25f3ce8da49ce Amir Goldstein          2022-05-07  502  		 * Send FS_RENAME to groups watching the moved inode itself
d25f3ce8da49ce Amir Goldstein          2022-05-07  503  		 * only if the moved inode is a non-dir.
d25f3ce8da49ce Amir Goldstein          2022-05-07  504  		 * Sending FS_RENAME to a moved watched directory would be
d25f3ce8da49ce Amir Goldstein          2022-05-07  505  		 * confusing and FS_MOVE_SELF provided enough information to
d25f3ce8da49ce Amir Goldstein          2022-05-07  506  		 * track the movements of a watched directory.
d25f3ce8da49ce Amir Goldstein          2022-05-07  507  		 */
d25f3ce8da49ce Amir Goldstein          2022-05-07  508  		if (mask & FS_ISDIR)
d25f3ce8da49ce Amir Goldstein          2022-05-07  509  			inode = NULL;
40a100d3adc1ad Amir Goldstein          2020-07-22  510  	} else if (mask & FS_EVENT_ON_CHILD) {
40a100d3adc1ad Amir Goldstein          2020-07-22  511  		/*
fecc4559780d52 Amir Goldstein          2020-12-02  512  		 * Event on child - report on TYPE_PARENT to dir if it is
fecc4559780d52 Amir Goldstein          2020-12-02  513  		 * watching children and on TYPE_INODE to child.
40a100d3adc1ad Amir Goldstein          2020-07-22  514  		 */
d25f3ce8da49ce Amir Goldstein          2022-05-07  515  		dir1 = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07  516  		dir2 = NULL;
d25f3ce8da49ce Amir Goldstein          2022-05-07  517  		if (dir1->i_fsnotify_marks)
d25f3ce8da49ce Amir Goldstein          2022-05-07  518  			dir1_type = FSNOTIFY_ITER_TYPE_PARENT;
40a100d3adc1ad Amir Goldstein          2020-07-22  519  	}
497b0c5a7c0688 Amir Goldstein          2020-07-16  520  
7c49b8616460eb Dave Hansen             2015-09-04  521  	/*
7c49b8616460eb Dave Hansen             2015-09-04  522  	 * Optimization: srcu_read_lock() has a memory barrier which can
7c49b8616460eb Dave Hansen             2015-09-04  523  	 * be expensive.  It protects walking the *_fsnotify_marks lists.
7c49b8616460eb Dave Hansen             2015-09-04  524  	 * However, if we do not walk the lists, we do not have to do
7c49b8616460eb Dave Hansen             2015-09-04  525  	 * SRCU because we have no references to any objects and do not
7c49b8616460eb Dave Hansen             2015-09-04  526  	 * need SRCU to keep them "alive".
7c49b8616460eb Dave Hansen             2015-09-04  527  	 */
9b93f33105f5f9 Amir Goldstein          2020-07-16  528  	if (!sb->s_fsnotify_marks &&
497b0c5a7c0688 Amir Goldstein          2020-07-16  529  	    (!mnt || !mnt->mnt_fsnotify_marks) &&
9b93f33105f5f9 Amir Goldstein          2020-07-16  530  	    (!inode || !inode->i_fsnotify_marks) &&
d25f3ce8da49ce Amir Goldstein          2022-05-07  531  	    !dir1_type)
7c49b8616460eb Dave Hansen             2015-09-04  532  		return 0;
71d734103edfa2 Mel Gorman              2020-07-08  533  
9b93f33105f5f9 Amir Goldstein          2020-07-16  534  	marks_mask = sb->s_fsnotify_mask;
71d734103edfa2 Mel Gorman              2020-07-08  535  	if (mnt)
71d734103edfa2 Mel Gorman              2020-07-08  536  		marks_mask |= mnt->mnt_fsnotify_mask;
9b93f33105f5f9 Amir Goldstein          2020-07-16  537  	if (inode)
9b93f33105f5f9 Amir Goldstein          2020-07-16  538  		marks_mask |= inode->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  539  	if (dir1_type) {
d25f3ce8da49ce Amir Goldstein          2022-05-07 @540  		if (dir1)
d25f3ce8da49ce Amir Goldstein          2022-05-07  541  			marks_mask |= dir1->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  542  		if (dir2)
d25f3ce8da49ce Amir Goldstein          2022-05-07  543  			marks_mask |= dir2->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  544  	}
497b0c5a7c0688 Amir Goldstein          2020-07-16  545  
71d734103edfa2 Mel Gorman              2020-07-08  546  
613a807fe7c793 Eric Paris              2010-07-28  547  	/*
04e317ba72d079 Amir Goldstein          2022-02-23  548  	 * If this is a modify event we may need to clear some ignored masks.
04e317ba72d079 Amir Goldstein          2022-02-23  549  	 * In that case, the object with ignored masks will have the FS_MODIFY
04e317ba72d079 Amir Goldstein          2022-02-23  550  	 * event in its mask.
04e317ba72d079 Amir Goldstein          2022-02-23  551  	 * Otherwise, return if none of the marks care about this type of event.
613a807fe7c793 Eric Paris              2010-07-28  552  	 */
71d734103edfa2 Mel Gorman              2020-07-08  553  	test_mask = (mask & ALL_FSNOTIFY_EVENTS);
04e317ba72d079 Amir Goldstein          2022-02-23  554  	if (!(test_mask & marks_mask))
613a807fe7c793 Eric Paris              2010-07-28  555  		return 0;
75c1be487a690d Eric Paris              2010-07-28  556  
9385a84d7e1f65 Jan Kara                2016-11-10  557  	iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
75c1be487a690d Eric Paris              2010-07-28  558  
1c9007d62bea6f Amir Goldstein          2021-11-29  559  	iter_info.marks[FSNOTIFY_ITER_TYPE_SB] =
45a9fb3725d886 Amir Goldstein          2019-01-10  560  		fsnotify_first_mark(&sb->s_fsnotify_marks);
9bdda4e9cf2dce Amir Goldstein          2018-09-01  561  	if (mnt) {
1c9007d62bea6f Amir Goldstein          2021-11-29  562  		iter_info.marks[FSNOTIFY_ITER_TYPE_VFSMOUNT] =
3427ce71554123 Miklos Szeredi          2017-10-30  563  			fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
7131485a93679f Eric Paris              2009-12-17  564  	}
9b93f33105f5f9 Amir Goldstein          2020-07-16  565  	if (inode) {
1c9007d62bea6f Amir Goldstein          2021-11-29  566  		iter_info.marks[FSNOTIFY_ITER_TYPE_INODE] =
9b93f33105f5f9 Amir Goldstein          2020-07-16  567  			fsnotify_first_mark(&inode->i_fsnotify_marks);
9b93f33105f5f9 Amir Goldstein          2020-07-16  568  	}
d25f3ce8da49ce Amir Goldstein          2022-05-07  569  	if (dir1_type) {
d25f3ce8da49ce Amir Goldstein          2022-05-07  570  		if (dir1)
d25f3ce8da49ce Amir Goldstein          2022-05-07  571  			iter_info.marks[dir1_type] =
d25f3ce8da49ce Amir Goldstein          2022-05-07  572  				fsnotify_first_mark(&dir1->i_fsnotify_marks);
d25f3ce8da49ce Amir Goldstein          2022-05-07  573  		if (dir2)
d25f3ce8da49ce Amir Goldstein          2022-05-07  574  			iter_info.marks[FSNOTIFY_ITER_TYPE_NEW_DIR] =
d25f3ce8da49ce Amir Goldstein          2022-05-07  575  				fsnotify_first_mark(&dir2->i_fsnotify_marks);
497b0c5a7c0688 Amir Goldstein          2020-07-16  576  	}
75c1be487a690d Eric Paris              2010-07-28  577  
8edc6e1688fc8f Jan Kara                2014-11-13  578  	/*
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  579  	 * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  580  	 * ignore masks are properly reflected for mount/sb mark notifications.
8edc6e1688fc8f Jan Kara                2014-11-13  581  	 * That's why this traversal is so complicated...
8edc6e1688fc8f Jan Kara                2014-11-13  582  	 */
d9a6f30bb89309 Amir Goldstein          2018-04-20  583  	while (fsnotify_iter_select_report_types(&iter_info)) {
b54cecf5e2293d Amir Goldstein          2020-06-07  584  		ret = send_to_group(mask, data, data_type, dir, file_name,
b54cecf5e2293d Amir Goldstein          2020-06-07  585  				    cookie, &iter_info);
613a807fe7c793 Eric Paris              2010-07-28  586  
ff8bcbd03da881 Eric Paris              2010-10-28  587  		if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
ff8bcbd03da881 Eric Paris              2010-10-28  588  			goto out;
ff8bcbd03da881 Eric Paris              2010-10-28  589  
d9a6f30bb89309 Amir Goldstein          2018-04-20  590  		fsnotify_iter_next(&iter_info);
90586523eb4b34 Eric Paris              2009-05-21  591  	}
ff8bcbd03da881 Eric Paris              2010-10-28  592  	ret = 0;
ff8bcbd03da881 Eric Paris              2010-10-28  593  out:
9385a84d7e1f65 Jan Kara                2016-11-10  594  	srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx);
c4ec54b40d33f8 Eric Paris              2009-12-17  595  
98b5c10d320adf Jean-Christophe Dubois  2010-03-23  596  	return ret;
90586523eb4b34 Eric Paris              2009-05-21  597  }
90586523eb4b34 Eric Paris              2009-05-21  598  EXPORT_SYMBOL_GPL(fsnotify);
90586523eb4b34 Eric Paris              2009-05-21  599  

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [amir73il:fsnotify-fixes 2/2] fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
@ 2022-05-09 10:08 ` Dan Carpenter
  0 siblings, 0 replies; 6+ messages in thread
From: Dan Carpenter @ 2022-05-09 10:08 UTC (permalink / raw)
  To: kbuild, Amir Goldstein; +Cc: lkp, kbuild-all, linux-kernel

tree:   https://github.com/amir73il/linux fsnotify-fixes
head:   d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6
commit: d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6 [2/2] fsnotify: send FS_RENAME to groups watching the moved inode
config: s390-randconfig-m031-20220508 (https://download.01.org/0day-ci/archive/20220508/202205080346.m0fb3UXK-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 11.3.0

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

smatch warnings:
fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)

vim +/dir1 +540 fs/notify/fsnotify.c

40a100d3adc1ad Amir Goldstein          2020-07-22  475  int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
40a100d3adc1ad Amir Goldstein          2020-07-22  476  	     const struct qstr *file_name, struct inode *inode, u32 cookie)
90586523eb4b34 Eric Paris              2009-05-21  477  {
b54cecf5e2293d Amir Goldstein          2020-06-07  478  	const struct path *path = fsnotify_data_path(data, data_type);
29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  479  	struct super_block *sb = fsnotify_data_sb(data, data_type);
3427ce71554123 Miklos Szeredi          2017-10-30  480  	struct fsnotify_iter_info iter_info = {};
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  481  	struct mount *mnt = NULL;
d25f3ce8da49ce Amir Goldstein          2022-05-07  482  	struct inode *dir1, *dir2;
e54183fa7047c1 Amir Goldstein          2021-11-29  483  	struct dentry *moved;
d25f3ce8da49ce Amir Goldstein          2022-05-07  484  	int dir1_type = 0;
9385a84d7e1f65 Jan Kara                2016-11-10  485  	int ret = 0;
71d734103edfa2 Mel Gorman              2020-07-08  486  	__u32 test_mask, marks_mask;
90586523eb4b34 Eric Paris              2009-05-21  487  
71d734103edfa2 Mel Gorman              2020-07-08  488  	if (path)
aa93bdc5500cc9 Amir Goldstein          2020-03-19  489  		mnt = real_mount(path->mnt);
3a9fb89f4cd04c Eric Paris              2009-12-17  490  
40a100d3adc1ad Amir Goldstein          2020-07-22  491  	if (!inode) {
40a100d3adc1ad Amir Goldstein          2020-07-22  492  		/* Dirent event - report on TYPE_INODE to dir */
40a100d3adc1ad Amir Goldstein          2020-07-22  493  		inode = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07  494  	} else if (mask & FS_RENAME) {
d25f3ce8da49ce Amir Goldstein          2022-05-07  495  		/* For FS_RENAME, dir1 is old_dir and dir2 is new_dir */
e54183fa7047c1 Amir Goldstein          2021-11-29  496  		moved = fsnotify_data_dentry(data, data_type);
d25f3ce8da49ce Amir Goldstein          2022-05-07  497  		dir1 = moved->d_parent->d_inode;
d25f3ce8da49ce Amir Goldstein          2022-05-07  498  		dir2 = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07 @499  		if (dir1->i_fsnotify_marks || dir2->i_fsnotify_marks)
                                                                            ^^^^^^^^^^^^^^^^^^^^^^
Dereference

d25f3ce8da49ce Amir Goldstein          2022-05-07  500  			dir1_type = FSNOTIFY_ITER_TYPE_OLD_DIR;
d25f3ce8da49ce Amir Goldstein          2022-05-07  501  		/*
d25f3ce8da49ce Amir Goldstein          2022-05-07  502  		 * Send FS_RENAME to groups watching the moved inode itself
d25f3ce8da49ce Amir Goldstein          2022-05-07  503  		 * only if the moved inode is a non-dir.
d25f3ce8da49ce Amir Goldstein          2022-05-07  504  		 * Sending FS_RENAME to a moved watched directory would be
d25f3ce8da49ce Amir Goldstein          2022-05-07  505  		 * confusing and FS_MOVE_SELF provided enough information to
d25f3ce8da49ce Amir Goldstein          2022-05-07  506  		 * track the movements of a watched directory.
d25f3ce8da49ce Amir Goldstein          2022-05-07  507  		 */
d25f3ce8da49ce Amir Goldstein          2022-05-07  508  		if (mask & FS_ISDIR)
d25f3ce8da49ce Amir Goldstein          2022-05-07  509  			inode = NULL;
40a100d3adc1ad Amir Goldstein          2020-07-22  510  	} else if (mask & FS_EVENT_ON_CHILD) {
40a100d3adc1ad Amir Goldstein          2020-07-22  511  		/*
fecc4559780d52 Amir Goldstein          2020-12-02  512  		 * Event on child - report on TYPE_PARENT to dir if it is
fecc4559780d52 Amir Goldstein          2020-12-02  513  		 * watching children and on TYPE_INODE to child.
40a100d3adc1ad Amir Goldstein          2020-07-22  514  		 */
d25f3ce8da49ce Amir Goldstein          2022-05-07  515  		dir1 = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07  516  		dir2 = NULL;
d25f3ce8da49ce Amir Goldstein          2022-05-07  517  		if (dir1->i_fsnotify_marks)
                                                                            ^^^^^^^^^^^^^^^^^^^^^^
Dereference

d25f3ce8da49ce Amir Goldstein          2022-05-07  518  			dir1_type = FSNOTIFY_ITER_TYPE_PARENT;
40a100d3adc1ad Amir Goldstein          2020-07-22  519  	}
497b0c5a7c0688 Amir Goldstein          2020-07-16  520  
7c49b8616460eb Dave Hansen             2015-09-04  521  	/*
7c49b8616460eb Dave Hansen             2015-09-04  522  	 * Optimization: srcu_read_lock() has a memory barrier which can
7c49b8616460eb Dave Hansen             2015-09-04  523  	 * be expensive.  It protects walking the *_fsnotify_marks lists.
7c49b8616460eb Dave Hansen             2015-09-04  524  	 * However, if we do not walk the lists, we do not have to do
7c49b8616460eb Dave Hansen             2015-09-04  525  	 * SRCU because we have no references to any objects and do not
7c49b8616460eb Dave Hansen             2015-09-04  526  	 * need SRCU to keep them "alive".
7c49b8616460eb Dave Hansen             2015-09-04  527  	 */
9b93f33105f5f9 Amir Goldstein          2020-07-16  528  	if (!sb->s_fsnotify_marks &&
497b0c5a7c0688 Amir Goldstein          2020-07-16  529  	    (!mnt || !mnt->mnt_fsnotify_marks) &&
9b93f33105f5f9 Amir Goldstein          2020-07-16  530  	    (!inode || !inode->i_fsnotify_marks) &&
d25f3ce8da49ce Amir Goldstein          2022-05-07  531  	    !dir1_type)
7c49b8616460eb Dave Hansen             2015-09-04  532  		return 0;
71d734103edfa2 Mel Gorman              2020-07-08  533  
9b93f33105f5f9 Amir Goldstein          2020-07-16  534  	marks_mask = sb->s_fsnotify_mask;
71d734103edfa2 Mel Gorman              2020-07-08  535  	if (mnt)
71d734103edfa2 Mel Gorman              2020-07-08  536  		marks_mask |= mnt->mnt_fsnotify_mask;
9b93f33105f5f9 Amir Goldstein          2020-07-16  537  	if (inode)
9b93f33105f5f9 Amir Goldstein          2020-07-16  538  		marks_mask |= inode->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  539  	if (dir1_type) {
d25f3ce8da49ce Amir Goldstein          2022-05-07 @540  		if (dir1)

If "dir1_type" is set then we have already dereferenced "dir1".  I guess
this unnecessary NULL check is something that probably wouldn't bother
a human reader too much...

d25f3ce8da49ce Amir Goldstein          2022-05-07  541  			marks_mask |= dir1->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  542  		if (dir2)
d25f3ce8da49ce Amir Goldstein          2022-05-07  543  			marks_mask |= dir2->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  544  	}
497b0c5a7c0688 Amir Goldstein          2020-07-16  545  
71d734103edfa2 Mel Gorman              2020-07-08  546  
613a807fe7c793 Eric Paris              2010-07-28  547  	/*
04e317ba72d079 Amir Goldstein          2022-02-23  548  	 * If this is a modify event we may need to clear some ignored masks.
04e317ba72d079 Amir Goldstein          2022-02-23  549  	 * In that case, the object with ignored masks will have the FS_MODIFY
04e317ba72d079 Amir Goldstein          2022-02-23  550  	 * event in its mask.
04e317ba72d079 Amir Goldstein          2022-02-23  551  	 * Otherwise, return if none of the marks care about this type of event.
613a807fe7c793 Eric Paris              2010-07-28  552  	 */
71d734103edfa2 Mel Gorman              2020-07-08  553  	test_mask = (mask & ALL_FSNOTIFY_EVENTS);
04e317ba72d079 Amir Goldstein          2022-02-23  554  	if (!(test_mask & marks_mask))
613a807fe7c793 Eric Paris              2010-07-28  555  		return 0;
75c1be487a690d Eric Paris              2010-07-28  556  
9385a84d7e1f65 Jan Kara                2016-11-10  557  	iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
75c1be487a690d Eric Paris              2010-07-28  558  
1c9007d62bea6f Amir Goldstein          2021-11-29  559  	iter_info.marks[FSNOTIFY_ITER_TYPE_SB] =
45a9fb3725d886 Amir Goldstein          2019-01-10  560  		fsnotify_first_mark(&sb->s_fsnotify_marks);
9bdda4e9cf2dce Amir Goldstein          2018-09-01  561  	if (mnt) {
1c9007d62bea6f Amir Goldstein          2021-11-29  562  		iter_info.marks[FSNOTIFY_ITER_TYPE_VFSMOUNT] =
3427ce71554123 Miklos Szeredi          2017-10-30  563  			fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
7131485a93679f Eric Paris              2009-12-17  564  	}
9b93f33105f5f9 Amir Goldstein          2020-07-16  565  	if (inode) {
1c9007d62bea6f Amir Goldstein          2021-11-29  566  		iter_info.marks[FSNOTIFY_ITER_TYPE_INODE] =
9b93f33105f5f9 Amir Goldstein          2020-07-16  567  			fsnotify_first_mark(&inode->i_fsnotify_marks);
9b93f33105f5f9 Amir Goldstein          2020-07-16  568  	}
d25f3ce8da49ce Amir Goldstein          2022-05-07  569  	if (dir1_type) {
d25f3ce8da49ce Amir Goldstein          2022-05-07  570  		if (dir1)
d25f3ce8da49ce Amir Goldstein          2022-05-07  571  			iter_info.marks[dir1_type] =
d25f3ce8da49ce Amir Goldstein          2022-05-07  572  				fsnotify_first_mark(&dir1->i_fsnotify_marks);
d25f3ce8da49ce Amir Goldstein          2022-05-07  573  		if (dir2)
d25f3ce8da49ce Amir Goldstein          2022-05-07  574  			iter_info.marks[FSNOTIFY_ITER_TYPE_NEW_DIR] =
d25f3ce8da49ce Amir Goldstein          2022-05-07  575  				fsnotify_first_mark(&dir2->i_fsnotify_marks);
497b0c5a7c0688 Amir Goldstein          2020-07-16  576  	}
75c1be487a690d Eric Paris              2010-07-28  577  
8edc6e1688fc8f Jan Kara                2014-11-13  578  	/*
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  579  	 * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  580  	 * ignore masks are properly reflected for mount/sb mark notifications.
8edc6e1688fc8f Jan Kara                2014-11-13  581  	 * That's why this traversal is so complicated...
8edc6e1688fc8f Jan Kara                2014-11-13  582  	 */
d9a6f30bb89309 Amir Goldstein          2018-04-20  583  	while (fsnotify_iter_select_report_types(&iter_info)) {
b54cecf5e2293d Amir Goldstein          2020-06-07  584  		ret = send_to_group(mask, data, data_type, dir, file_name,
b54cecf5e2293d Amir Goldstein          2020-06-07  585  				    cookie, &iter_info);
613a807fe7c793 Eric Paris              2010-07-28  586  
ff8bcbd03da881 Eric Paris              2010-10-28  587  		if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
ff8bcbd03da881 Eric Paris              2010-10-28  588  			goto out;
ff8bcbd03da881 Eric Paris              2010-10-28  589  
d9a6f30bb89309 Amir Goldstein          2018-04-20  590  		fsnotify_iter_next(&iter_info);
90586523eb4b34 Eric Paris              2009-05-21  591  	}
ff8bcbd03da881 Eric Paris              2010-10-28  592  	ret = 0;
ff8bcbd03da881 Eric Paris              2010-10-28  593  out:
9385a84d7e1f65 Jan Kara                2016-11-10  594  	srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx);
c4ec54b40d33f8 Eric Paris              2009-12-17  595  
98b5c10d320adf Jean-Christophe Dubois  2010-03-23  596  	return ret;
90586523eb4b34 Eric Paris              2009-05-21  597  }

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [amir73il:fsnotify-fixes 2/2] fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
@ 2022-05-09 10:08 ` Dan Carpenter
  0 siblings, 0 replies; 6+ messages in thread
From: Dan Carpenter @ 2022-05-09 10:08 UTC (permalink / raw)
  To: kbuild-all

[-- Attachment #1: Type: text/plain, Size: 11873 bytes --]

tree:   https://github.com/amir73il/linux fsnotify-fixes
head:   d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6
commit: d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6 [2/2] fsnotify: send FS_RENAME to groups watching the moved inode
config: s390-randconfig-m031-20220508 (https://download.01.org/0day-ci/archive/20220508/202205080346.m0fb3UXK-lkp(a)intel.com/config)
compiler: s390-linux-gcc (GCC) 11.3.0

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

smatch warnings:
fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)

vim +/dir1 +540 fs/notify/fsnotify.c

40a100d3adc1ad Amir Goldstein          2020-07-22  475  int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
40a100d3adc1ad Amir Goldstein          2020-07-22  476  	     const struct qstr *file_name, struct inode *inode, u32 cookie)
90586523eb4b34 Eric Paris              2009-05-21  477  {
b54cecf5e2293d Amir Goldstein          2020-06-07  478  	const struct path *path = fsnotify_data_path(data, data_type);
29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  479  	struct super_block *sb = fsnotify_data_sb(data, data_type);
3427ce71554123 Miklos Szeredi          2017-10-30  480  	struct fsnotify_iter_info iter_info = {};
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  481  	struct mount *mnt = NULL;
d25f3ce8da49ce Amir Goldstein          2022-05-07  482  	struct inode *dir1, *dir2;
e54183fa7047c1 Amir Goldstein          2021-11-29  483  	struct dentry *moved;
d25f3ce8da49ce Amir Goldstein          2022-05-07  484  	int dir1_type = 0;
9385a84d7e1f65 Jan Kara                2016-11-10  485  	int ret = 0;
71d734103edfa2 Mel Gorman              2020-07-08  486  	__u32 test_mask, marks_mask;
90586523eb4b34 Eric Paris              2009-05-21  487  
71d734103edfa2 Mel Gorman              2020-07-08  488  	if (path)
aa93bdc5500cc9 Amir Goldstein          2020-03-19  489  		mnt = real_mount(path->mnt);
3a9fb89f4cd04c Eric Paris              2009-12-17  490  
40a100d3adc1ad Amir Goldstein          2020-07-22  491  	if (!inode) {
40a100d3adc1ad Amir Goldstein          2020-07-22  492  		/* Dirent event - report on TYPE_INODE to dir */
40a100d3adc1ad Amir Goldstein          2020-07-22  493  		inode = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07  494  	} else if (mask & FS_RENAME) {
d25f3ce8da49ce Amir Goldstein          2022-05-07  495  		/* For FS_RENAME, dir1 is old_dir and dir2 is new_dir */
e54183fa7047c1 Amir Goldstein          2021-11-29  496  		moved = fsnotify_data_dentry(data, data_type);
d25f3ce8da49ce Amir Goldstein          2022-05-07  497  		dir1 = moved->d_parent->d_inode;
d25f3ce8da49ce Amir Goldstein          2022-05-07  498  		dir2 = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07 @499  		if (dir1->i_fsnotify_marks || dir2->i_fsnotify_marks)
                                                                            ^^^^^^^^^^^^^^^^^^^^^^
Dereference

d25f3ce8da49ce Amir Goldstein          2022-05-07  500  			dir1_type = FSNOTIFY_ITER_TYPE_OLD_DIR;
d25f3ce8da49ce Amir Goldstein          2022-05-07  501  		/*
d25f3ce8da49ce Amir Goldstein          2022-05-07  502  		 * Send FS_RENAME to groups watching the moved inode itself
d25f3ce8da49ce Amir Goldstein          2022-05-07  503  		 * only if the moved inode is a non-dir.
d25f3ce8da49ce Amir Goldstein          2022-05-07  504  		 * Sending FS_RENAME to a moved watched directory would be
d25f3ce8da49ce Amir Goldstein          2022-05-07  505  		 * confusing and FS_MOVE_SELF provided enough information to
d25f3ce8da49ce Amir Goldstein          2022-05-07  506  		 * track the movements of a watched directory.
d25f3ce8da49ce Amir Goldstein          2022-05-07  507  		 */
d25f3ce8da49ce Amir Goldstein          2022-05-07  508  		if (mask & FS_ISDIR)
d25f3ce8da49ce Amir Goldstein          2022-05-07  509  			inode = NULL;
40a100d3adc1ad Amir Goldstein          2020-07-22  510  	} else if (mask & FS_EVENT_ON_CHILD) {
40a100d3adc1ad Amir Goldstein          2020-07-22  511  		/*
fecc4559780d52 Amir Goldstein          2020-12-02  512  		 * Event on child - report on TYPE_PARENT to dir if it is
fecc4559780d52 Amir Goldstein          2020-12-02  513  		 * watching children and on TYPE_INODE to child.
40a100d3adc1ad Amir Goldstein          2020-07-22  514  		 */
d25f3ce8da49ce Amir Goldstein          2022-05-07  515  		dir1 = dir;
d25f3ce8da49ce Amir Goldstein          2022-05-07  516  		dir2 = NULL;
d25f3ce8da49ce Amir Goldstein          2022-05-07  517  		if (dir1->i_fsnotify_marks)
                                                                            ^^^^^^^^^^^^^^^^^^^^^^
Dereference

d25f3ce8da49ce Amir Goldstein          2022-05-07  518  			dir1_type = FSNOTIFY_ITER_TYPE_PARENT;
40a100d3adc1ad Amir Goldstein          2020-07-22  519  	}
497b0c5a7c0688 Amir Goldstein          2020-07-16  520  
7c49b8616460eb Dave Hansen             2015-09-04  521  	/*
7c49b8616460eb Dave Hansen             2015-09-04  522  	 * Optimization: srcu_read_lock() has a memory barrier which can
7c49b8616460eb Dave Hansen             2015-09-04  523  	 * be expensive.  It protects walking the *_fsnotify_marks lists.
7c49b8616460eb Dave Hansen             2015-09-04  524  	 * However, if we do not walk the lists, we do not have to do
7c49b8616460eb Dave Hansen             2015-09-04  525  	 * SRCU because we have no references to any objects and do not
7c49b8616460eb Dave Hansen             2015-09-04  526  	 * need SRCU to keep them "alive".
7c49b8616460eb Dave Hansen             2015-09-04  527  	 */
9b93f33105f5f9 Amir Goldstein          2020-07-16  528  	if (!sb->s_fsnotify_marks &&
497b0c5a7c0688 Amir Goldstein          2020-07-16  529  	    (!mnt || !mnt->mnt_fsnotify_marks) &&
9b93f33105f5f9 Amir Goldstein          2020-07-16  530  	    (!inode || !inode->i_fsnotify_marks) &&
d25f3ce8da49ce Amir Goldstein          2022-05-07  531  	    !dir1_type)
7c49b8616460eb Dave Hansen             2015-09-04  532  		return 0;
71d734103edfa2 Mel Gorman              2020-07-08  533  
9b93f33105f5f9 Amir Goldstein          2020-07-16  534  	marks_mask = sb->s_fsnotify_mask;
71d734103edfa2 Mel Gorman              2020-07-08  535  	if (mnt)
71d734103edfa2 Mel Gorman              2020-07-08  536  		marks_mask |= mnt->mnt_fsnotify_mask;
9b93f33105f5f9 Amir Goldstein          2020-07-16  537  	if (inode)
9b93f33105f5f9 Amir Goldstein          2020-07-16  538  		marks_mask |= inode->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  539  	if (dir1_type) {
d25f3ce8da49ce Amir Goldstein          2022-05-07 @540  		if (dir1)

If "dir1_type" is set then we have already dereferenced "dir1".  I guess
this unnecessary NULL check is something that probably wouldn't bother
a human reader too much...

d25f3ce8da49ce Amir Goldstein          2022-05-07  541  			marks_mask |= dir1->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  542  		if (dir2)
d25f3ce8da49ce Amir Goldstein          2022-05-07  543  			marks_mask |= dir2->i_fsnotify_mask;
d25f3ce8da49ce Amir Goldstein          2022-05-07  544  	}
497b0c5a7c0688 Amir Goldstein          2020-07-16  545  
71d734103edfa2 Mel Gorman              2020-07-08  546  
613a807fe7c793 Eric Paris              2010-07-28  547  	/*
04e317ba72d079 Amir Goldstein          2022-02-23  548  	 * If this is a modify event we may need to clear some ignored masks.
04e317ba72d079 Amir Goldstein          2022-02-23  549  	 * In that case, the object with ignored masks will have the FS_MODIFY
04e317ba72d079 Amir Goldstein          2022-02-23  550  	 * event in its mask.
04e317ba72d079 Amir Goldstein          2022-02-23  551  	 * Otherwise, return if none of the marks care about this type of event.
613a807fe7c793 Eric Paris              2010-07-28  552  	 */
71d734103edfa2 Mel Gorman              2020-07-08  553  	test_mask = (mask & ALL_FSNOTIFY_EVENTS);
04e317ba72d079 Amir Goldstein          2022-02-23  554  	if (!(test_mask & marks_mask))
613a807fe7c793 Eric Paris              2010-07-28  555  		return 0;
75c1be487a690d Eric Paris              2010-07-28  556  
9385a84d7e1f65 Jan Kara                2016-11-10  557  	iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
75c1be487a690d Eric Paris              2010-07-28  558  
1c9007d62bea6f Amir Goldstein          2021-11-29  559  	iter_info.marks[FSNOTIFY_ITER_TYPE_SB] =
45a9fb3725d886 Amir Goldstein          2019-01-10  560  		fsnotify_first_mark(&sb->s_fsnotify_marks);
9bdda4e9cf2dce Amir Goldstein          2018-09-01  561  	if (mnt) {
1c9007d62bea6f Amir Goldstein          2021-11-29  562  		iter_info.marks[FSNOTIFY_ITER_TYPE_VFSMOUNT] =
3427ce71554123 Miklos Szeredi          2017-10-30  563  			fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
7131485a93679f Eric Paris              2009-12-17  564  	}
9b93f33105f5f9 Amir Goldstein          2020-07-16  565  	if (inode) {
1c9007d62bea6f Amir Goldstein          2021-11-29  566  		iter_info.marks[FSNOTIFY_ITER_TYPE_INODE] =
9b93f33105f5f9 Amir Goldstein          2020-07-16  567  			fsnotify_first_mark(&inode->i_fsnotify_marks);
9b93f33105f5f9 Amir Goldstein          2020-07-16  568  	}
d25f3ce8da49ce Amir Goldstein          2022-05-07  569  	if (dir1_type) {
d25f3ce8da49ce Amir Goldstein          2022-05-07  570  		if (dir1)
d25f3ce8da49ce Amir Goldstein          2022-05-07  571  			iter_info.marks[dir1_type] =
d25f3ce8da49ce Amir Goldstein          2022-05-07  572  				fsnotify_first_mark(&dir1->i_fsnotify_marks);
d25f3ce8da49ce Amir Goldstein          2022-05-07  573  		if (dir2)
d25f3ce8da49ce Amir Goldstein          2022-05-07  574  			iter_info.marks[FSNOTIFY_ITER_TYPE_NEW_DIR] =
d25f3ce8da49ce Amir Goldstein          2022-05-07  575  				fsnotify_first_mark(&dir2->i_fsnotify_marks);
497b0c5a7c0688 Amir Goldstein          2020-07-16  576  	}
75c1be487a690d Eric Paris              2010-07-28  577  
8edc6e1688fc8f Jan Kara                2014-11-13  578  	/*
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  579  	 * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark
60f7ed8c7c4d06 Amir Goldstein          2018-09-01  580  	 * ignore masks are properly reflected for mount/sb mark notifications.
8edc6e1688fc8f Jan Kara                2014-11-13  581  	 * That's why this traversal is so complicated...
8edc6e1688fc8f Jan Kara                2014-11-13  582  	 */
d9a6f30bb89309 Amir Goldstein          2018-04-20  583  	while (fsnotify_iter_select_report_types(&iter_info)) {
b54cecf5e2293d Amir Goldstein          2020-06-07  584  		ret = send_to_group(mask, data, data_type, dir, file_name,
b54cecf5e2293d Amir Goldstein          2020-06-07  585  				    cookie, &iter_info);
613a807fe7c793 Eric Paris              2010-07-28  586  
ff8bcbd03da881 Eric Paris              2010-10-28  587  		if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
ff8bcbd03da881 Eric Paris              2010-10-28  588  			goto out;
ff8bcbd03da881 Eric Paris              2010-10-28  589  
d9a6f30bb89309 Amir Goldstein          2018-04-20  590  		fsnotify_iter_next(&iter_info);
90586523eb4b34 Eric Paris              2009-05-21  591  	}
ff8bcbd03da881 Eric Paris              2010-10-28  592  	ret = 0;
ff8bcbd03da881 Eric Paris              2010-10-28  593  out:
9385a84d7e1f65 Jan Kara                2016-11-10  594  	srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx);
c4ec54b40d33f8 Eric Paris              2009-12-17  595  
98b5c10d320adf Jean-Christophe Dubois  2010-03-23  596  	return ret;
90586523eb4b34 Eric Paris              2009-05-21  597  }

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [amir73il:fsnotify-fixes 2/2] fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
  2022-05-09 10:08 ` Dan Carpenter
@ 2022-05-09 11:48   ` Amir Goldstein
  -1 siblings, 0 replies; 6+ messages in thread
From: Amir Goldstein @ 2022-05-09 11:48 UTC (permalink / raw)
  To: Dan Carpenter
  Cc: kbuild, kbuild test robot, kbuild-all, linux-kernel,
	Matthew Bobrowski, Jan Kara

On Mon, May 9, 2022 at 1:09 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> tree:   https://github.com/amir73il/linux fsnotify-fixes
> head:   d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6
> commit: d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6 [2/2] fsnotify: send FS_RENAME to groups watching the moved inode
> config: s390-randconfig-m031-20220508 (https://download.01.org/0day-ci/archive/20220508/202205080346.m0fb3UXK-lkp@intel.com/config)
> compiler: s390-linux-gcc (GCC) 11.3.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> smatch warnings:
> fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
>
> vim +/dir1 +540 fs/notify/fsnotify.c
>
> 40a100d3adc1ad Amir Goldstein          2020-07-22  475  int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
> 40a100d3adc1ad Amir Goldstein          2020-07-22  476               const struct qstr *file_name, struct inode *inode, u32 cookie)
> 90586523eb4b34 Eric Paris              2009-05-21  477  {
> b54cecf5e2293d Amir Goldstein          2020-06-07  478          const struct path *path = fsnotify_data_path(data, data_type);
> 29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  479          struct super_block *sb = fsnotify_data_sb(data, data_type);
> 3427ce71554123 Miklos Szeredi          2017-10-30  480          struct fsnotify_iter_info iter_info = {};
> 60f7ed8c7c4d06 Amir Goldstein          2018-09-01  481          struct mount *mnt = NULL;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  482          struct inode *dir1, *dir2;
> e54183fa7047c1 Amir Goldstein          2021-11-29  483          struct dentry *moved;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  484          int dir1_type = 0;
> 9385a84d7e1f65 Jan Kara                2016-11-10  485          int ret = 0;
> 71d734103edfa2 Mel Gorman              2020-07-08  486          __u32 test_mask, marks_mask;
> 90586523eb4b34 Eric Paris              2009-05-21  487
> 71d734103edfa2 Mel Gorman              2020-07-08  488          if (path)
> aa93bdc5500cc9 Amir Goldstein          2020-03-19  489                  mnt = real_mount(path->mnt);
> 3a9fb89f4cd04c Eric Paris              2009-12-17  490
> 40a100d3adc1ad Amir Goldstein          2020-07-22  491          if (!inode) {
> 40a100d3adc1ad Amir Goldstein          2020-07-22  492                  /* Dirent event - report on TYPE_INODE to dir */
> 40a100d3adc1ad Amir Goldstein          2020-07-22  493                  inode = dir;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  494          } else if (mask & FS_RENAME) {
> d25f3ce8da49ce Amir Goldstein          2022-05-07  495                  /* For FS_RENAME, dir1 is old_dir and dir2 is new_dir */
> e54183fa7047c1 Amir Goldstein          2021-11-29  496                  moved = fsnotify_data_dentry(data, data_type);
> d25f3ce8da49ce Amir Goldstein          2022-05-07  497                  dir1 = moved->d_parent->d_inode;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  498                  dir2 = dir;
> d25f3ce8da49ce Amir Goldstein          2022-05-07 @499                  if (dir1->i_fsnotify_marks || dir2->i_fsnotify_marks)
>                                                                             ^^^^^^^^^^^^^^^^^^^^^^
> Dereference
>
> d25f3ce8da49ce Amir Goldstein          2022-05-07  500                          dir1_type = FSNOTIFY_ITER_TYPE_OLD_DIR;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  501                  /*
> d25f3ce8da49ce Amir Goldstein          2022-05-07  502                   * Send FS_RENAME to groups watching the moved inode itself
> d25f3ce8da49ce Amir Goldstein          2022-05-07  503                   * only if the moved inode is a non-dir.
> d25f3ce8da49ce Amir Goldstein          2022-05-07  504                   * Sending FS_RENAME to a moved watched directory would be
> d25f3ce8da49ce Amir Goldstein          2022-05-07  505                   * confusing and FS_MOVE_SELF provided enough information to
> d25f3ce8da49ce Amir Goldstein          2022-05-07  506                   * track the movements of a watched directory.
> d25f3ce8da49ce Amir Goldstein          2022-05-07  507                   */
> d25f3ce8da49ce Amir Goldstein          2022-05-07  508                  if (mask & FS_ISDIR)
> d25f3ce8da49ce Amir Goldstein          2022-05-07  509                          inode = NULL;
> 40a100d3adc1ad Amir Goldstein          2020-07-22  510          } else if (mask & FS_EVENT_ON_CHILD) {
> 40a100d3adc1ad Amir Goldstein          2020-07-22  511                  /*
> fecc4559780d52 Amir Goldstein          2020-12-02  512                   * Event on child - report on TYPE_PARENT to dir if it is
> fecc4559780d52 Amir Goldstein          2020-12-02  513                   * watching children and on TYPE_INODE to child.
> 40a100d3adc1ad Amir Goldstein          2020-07-22  514                   */
> d25f3ce8da49ce Amir Goldstein          2022-05-07  515                  dir1 = dir;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  516                  dir2 = NULL;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  517                  if (dir1->i_fsnotify_marks)
>                                                                             ^^^^^^^^^^^^^^^^^^^^^^
> Dereference
>
> d25f3ce8da49ce Amir Goldstein          2022-05-07  518                          dir1_type = FSNOTIFY_ITER_TYPE_PARENT;
> 40a100d3adc1ad Amir Goldstein          2020-07-22  519          }
> 497b0c5a7c0688 Amir Goldstein          2020-07-16  520
> 7c49b8616460eb Dave Hansen             2015-09-04  521          /*
> 7c49b8616460eb Dave Hansen             2015-09-04  522           * Optimization: srcu_read_lock() has a memory barrier which can
> 7c49b8616460eb Dave Hansen             2015-09-04  523           * be expensive.  It protects walking the *_fsnotify_marks lists.
> 7c49b8616460eb Dave Hansen             2015-09-04  524           * However, if we do not walk the lists, we do not have to do
> 7c49b8616460eb Dave Hansen             2015-09-04  525           * SRCU because we have no references to any objects and do not
> 7c49b8616460eb Dave Hansen             2015-09-04  526           * need SRCU to keep them "alive".
> 7c49b8616460eb Dave Hansen             2015-09-04  527           */
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  528          if (!sb->s_fsnotify_marks &&
> 497b0c5a7c0688 Amir Goldstein          2020-07-16  529              (!mnt || !mnt->mnt_fsnotify_marks) &&
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  530              (!inode || !inode->i_fsnotify_marks) &&
> d25f3ce8da49ce Amir Goldstein          2022-05-07  531              !dir1_type)
> 7c49b8616460eb Dave Hansen             2015-09-04  532                  return 0;
> 71d734103edfa2 Mel Gorman              2020-07-08  533
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  534          marks_mask = sb->s_fsnotify_mask;
> 71d734103edfa2 Mel Gorman              2020-07-08  535          if (mnt)
> 71d734103edfa2 Mel Gorman              2020-07-08  536                  marks_mask |= mnt->mnt_fsnotify_mask;
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  537          if (inode)
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  538                  marks_mask |= inode->i_fsnotify_mask;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  539          if (dir1_type) {
> d25f3ce8da49ce Amir Goldstein          2022-05-07 @540                  if (dir1)
>
> If "dir1_type" is set then we have already dereferenced "dir1".  I guess
> this unnecessary NULL check is something that probably wouldn't bother
> a human reader too much...

True !!dir1_type means !!dir1.
We could get rid of if (dir1)
but I should note that I did not post this patch for review, this is an untested
patch that I pushed to a branch on my private github.
It is very generous of kbuild testbot to test any branch I push to my
private github,
but as much as I can recall, I never asked for it...

Thanks,
Amir.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [amir73il:fsnotify-fixes 2/2] fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
@ 2022-05-09 11:48   ` Amir Goldstein
  0 siblings, 0 replies; 6+ messages in thread
From: Amir Goldstein @ 2022-05-09 11:48 UTC (permalink / raw)
  To: kbuild-all

[-- Attachment #1: Type: text/plain, Size: 8245 bytes --]

On Mon, May 9, 2022 at 1:09 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> tree:   https://github.com/amir73il/linux fsnotify-fixes
> head:   d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6
> commit: d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6 [2/2] fsnotify: send FS_RENAME to groups watching the moved inode
> config: s390-randconfig-m031-20220508 (https://download.01.org/0day-ci/archive/20220508/202205080346.m0fb3UXK-lkp(a)intel.com/config)
> compiler: s390-linux-gcc (GCC) 11.3.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> smatch warnings:
> fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
>
> vim +/dir1 +540 fs/notify/fsnotify.c
>
> 40a100d3adc1ad Amir Goldstein          2020-07-22  475  int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
> 40a100d3adc1ad Amir Goldstein          2020-07-22  476               const struct qstr *file_name, struct inode *inode, u32 cookie)
> 90586523eb4b34 Eric Paris              2009-05-21  477  {
> b54cecf5e2293d Amir Goldstein          2020-06-07  478          const struct path *path = fsnotify_data_path(data, data_type);
> 29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  479          struct super_block *sb = fsnotify_data_sb(data, data_type);
> 3427ce71554123 Miklos Szeredi          2017-10-30  480          struct fsnotify_iter_info iter_info = {};
> 60f7ed8c7c4d06 Amir Goldstein          2018-09-01  481          struct mount *mnt = NULL;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  482          struct inode *dir1, *dir2;
> e54183fa7047c1 Amir Goldstein          2021-11-29  483          struct dentry *moved;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  484          int dir1_type = 0;
> 9385a84d7e1f65 Jan Kara                2016-11-10  485          int ret = 0;
> 71d734103edfa2 Mel Gorman              2020-07-08  486          __u32 test_mask, marks_mask;
> 90586523eb4b34 Eric Paris              2009-05-21  487
> 71d734103edfa2 Mel Gorman              2020-07-08  488          if (path)
> aa93bdc5500cc9 Amir Goldstein          2020-03-19  489                  mnt = real_mount(path->mnt);
> 3a9fb89f4cd04c Eric Paris              2009-12-17  490
> 40a100d3adc1ad Amir Goldstein          2020-07-22  491          if (!inode) {
> 40a100d3adc1ad Amir Goldstein          2020-07-22  492                  /* Dirent event - report on TYPE_INODE to dir */
> 40a100d3adc1ad Amir Goldstein          2020-07-22  493                  inode = dir;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  494          } else if (mask & FS_RENAME) {
> d25f3ce8da49ce Amir Goldstein          2022-05-07  495                  /* For FS_RENAME, dir1 is old_dir and dir2 is new_dir */
> e54183fa7047c1 Amir Goldstein          2021-11-29  496                  moved = fsnotify_data_dentry(data, data_type);
> d25f3ce8da49ce Amir Goldstein          2022-05-07  497                  dir1 = moved->d_parent->d_inode;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  498                  dir2 = dir;
> d25f3ce8da49ce Amir Goldstein          2022-05-07 @499                  if (dir1->i_fsnotify_marks || dir2->i_fsnotify_marks)
>                                                                             ^^^^^^^^^^^^^^^^^^^^^^
> Dereference
>
> d25f3ce8da49ce Amir Goldstein          2022-05-07  500                          dir1_type = FSNOTIFY_ITER_TYPE_OLD_DIR;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  501                  /*
> d25f3ce8da49ce Amir Goldstein          2022-05-07  502                   * Send FS_RENAME to groups watching the moved inode itself
> d25f3ce8da49ce Amir Goldstein          2022-05-07  503                   * only if the moved inode is a non-dir.
> d25f3ce8da49ce Amir Goldstein          2022-05-07  504                   * Sending FS_RENAME to a moved watched directory would be
> d25f3ce8da49ce Amir Goldstein          2022-05-07  505                   * confusing and FS_MOVE_SELF provided enough information to
> d25f3ce8da49ce Amir Goldstein          2022-05-07  506                   * track the movements of a watched directory.
> d25f3ce8da49ce Amir Goldstein          2022-05-07  507                   */
> d25f3ce8da49ce Amir Goldstein          2022-05-07  508                  if (mask & FS_ISDIR)
> d25f3ce8da49ce Amir Goldstein          2022-05-07  509                          inode = NULL;
> 40a100d3adc1ad Amir Goldstein          2020-07-22  510          } else if (mask & FS_EVENT_ON_CHILD) {
> 40a100d3adc1ad Amir Goldstein          2020-07-22  511                  /*
> fecc4559780d52 Amir Goldstein          2020-12-02  512                   * Event on child - report on TYPE_PARENT to dir if it is
> fecc4559780d52 Amir Goldstein          2020-12-02  513                   * watching children and on TYPE_INODE to child.
> 40a100d3adc1ad Amir Goldstein          2020-07-22  514                   */
> d25f3ce8da49ce Amir Goldstein          2022-05-07  515                  dir1 = dir;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  516                  dir2 = NULL;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  517                  if (dir1->i_fsnotify_marks)
>                                                                             ^^^^^^^^^^^^^^^^^^^^^^
> Dereference
>
> d25f3ce8da49ce Amir Goldstein          2022-05-07  518                          dir1_type = FSNOTIFY_ITER_TYPE_PARENT;
> 40a100d3adc1ad Amir Goldstein          2020-07-22  519          }
> 497b0c5a7c0688 Amir Goldstein          2020-07-16  520
> 7c49b8616460eb Dave Hansen             2015-09-04  521          /*
> 7c49b8616460eb Dave Hansen             2015-09-04  522           * Optimization: srcu_read_lock() has a memory barrier which can
> 7c49b8616460eb Dave Hansen             2015-09-04  523           * be expensive.  It protects walking the *_fsnotify_marks lists.
> 7c49b8616460eb Dave Hansen             2015-09-04  524           * However, if we do not walk the lists, we do not have to do
> 7c49b8616460eb Dave Hansen             2015-09-04  525           * SRCU because we have no references to any objects and do not
> 7c49b8616460eb Dave Hansen             2015-09-04  526           * need SRCU to keep them "alive".
> 7c49b8616460eb Dave Hansen             2015-09-04  527           */
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  528          if (!sb->s_fsnotify_marks &&
> 497b0c5a7c0688 Amir Goldstein          2020-07-16  529              (!mnt || !mnt->mnt_fsnotify_marks) &&
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  530              (!inode || !inode->i_fsnotify_marks) &&
> d25f3ce8da49ce Amir Goldstein          2022-05-07  531              !dir1_type)
> 7c49b8616460eb Dave Hansen             2015-09-04  532                  return 0;
> 71d734103edfa2 Mel Gorman              2020-07-08  533
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  534          marks_mask = sb->s_fsnotify_mask;
> 71d734103edfa2 Mel Gorman              2020-07-08  535          if (mnt)
> 71d734103edfa2 Mel Gorman              2020-07-08  536                  marks_mask |= mnt->mnt_fsnotify_mask;
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  537          if (inode)
> 9b93f33105f5f9 Amir Goldstein          2020-07-16  538                  marks_mask |= inode->i_fsnotify_mask;
> d25f3ce8da49ce Amir Goldstein          2022-05-07  539          if (dir1_type) {
> d25f3ce8da49ce Amir Goldstein          2022-05-07 @540                  if (dir1)
>
> If "dir1_type" is set then we have already dereferenced "dir1".  I guess
> this unnecessary NULL check is something that probably wouldn't bother
> a human reader too much...

True !!dir1_type means !!dir1.
We could get rid of if (dir1)
but I should note that I did not post this patch for review, this is an untested
patch that I pushed to a branch on my private github.
It is very generous of kbuild testbot to test any branch I push to my
private github,
but as much as I can recall, I never asked for it...

Thanks,
Amir.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [kbuild-all] Re: [amir73il:fsnotify-fixes 2/2] fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
  2022-05-09 11:48   ` Amir Goldstein
  (?)
@ 2022-05-12  9:32   ` Chen, Rong A
  -1 siblings, 0 replies; 6+ messages in thread
From: Chen, Rong A @ 2022-05-12  9:32 UTC (permalink / raw)
  To: Amir Goldstein, Dan Carpenter
  Cc: kbuild, kbuild test robot, kbuild-all, linux-kernel,
	Matthew Bobrowski, Jan Kara



On 5/9/2022 7:48 PM, Amir Goldstein wrote:
> On Mon, May 9, 2022 at 1:09 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>>
>> tree:   https://github.com/amir73il/linux fsnotify-fixes
>> head:   d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6
>> commit: d25f3ce8da49ce1a3b0a0621f0bf7b1d6ba2dad6 [2/2] fsnotify: send FS_RENAME to groups watching the moved inode
>> config: s390-randconfig-m031-20220508 (https://download.01.org/0day-ci/archive/20220508/202205080346.m0fb3UXK-lkp@intel.com/config)
>> compiler: s390-linux-gcc (GCC) 11.3.0
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>>
>> smatch warnings:
>> fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499)
>>
>> vim +/dir1 +540 fs/notify/fsnotify.c
>>
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  475  int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  476               const struct qstr *file_name, struct inode *inode, u32 cookie)
>> 90586523eb4b34 Eric Paris              2009-05-21  477  {
>> b54cecf5e2293d Amir Goldstein          2020-06-07  478          const struct path *path = fsnotify_data_path(data, data_type);
>> 29335033c574a1 Gabriel Krisman Bertazi 2021-10-25  479          struct super_block *sb = fsnotify_data_sb(data, data_type);
>> 3427ce71554123 Miklos Szeredi          2017-10-30  480          struct fsnotify_iter_info iter_info = {};
>> 60f7ed8c7c4d06 Amir Goldstein          2018-09-01  481          struct mount *mnt = NULL;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  482          struct inode *dir1, *dir2;
>> e54183fa7047c1 Amir Goldstein          2021-11-29  483          struct dentry *moved;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  484          int dir1_type = 0;
>> 9385a84d7e1f65 Jan Kara                2016-11-10  485          int ret = 0;
>> 71d734103edfa2 Mel Gorman              2020-07-08  486          __u32 test_mask, marks_mask;
>> 90586523eb4b34 Eric Paris              2009-05-21  487
>> 71d734103edfa2 Mel Gorman              2020-07-08  488          if (path)
>> aa93bdc5500cc9 Amir Goldstein          2020-03-19  489                  mnt = real_mount(path->mnt);
>> 3a9fb89f4cd04c Eric Paris              2009-12-17  490
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  491          if (!inode) {
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  492                  /* Dirent event - report on TYPE_INODE to dir */
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  493                  inode = dir;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  494          } else if (mask & FS_RENAME) {
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  495                  /* For FS_RENAME, dir1 is old_dir and dir2 is new_dir */
>> e54183fa7047c1 Amir Goldstein          2021-11-29  496                  moved = fsnotify_data_dentry(data, data_type);
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  497                  dir1 = moved->d_parent->d_inode;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  498                  dir2 = dir;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07 @499                  if (dir1->i_fsnotify_marks || dir2->i_fsnotify_marks)
>>                                                                              ^^^^^^^^^^^^^^^^^^^^^^
>> Dereference
>>
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  500                          dir1_type = FSNOTIFY_ITER_TYPE_OLD_DIR;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  501                  /*
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  502                   * Send FS_RENAME to groups watching the moved inode itself
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  503                   * only if the moved inode is a non-dir.
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  504                   * Sending FS_RENAME to a moved watched directory would be
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  505                   * confusing and FS_MOVE_SELF provided enough information to
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  506                   * track the movements of a watched directory.
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  507                   */
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  508                  if (mask & FS_ISDIR)
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  509                          inode = NULL;
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  510          } else if (mask & FS_EVENT_ON_CHILD) {
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  511                  /*
>> fecc4559780d52 Amir Goldstein          2020-12-02  512                   * Event on child - report on TYPE_PARENT to dir if it is
>> fecc4559780d52 Amir Goldstein          2020-12-02  513                   * watching children and on TYPE_INODE to child.
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  514                   */
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  515                  dir1 = dir;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  516                  dir2 = NULL;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  517                  if (dir1->i_fsnotify_marks)
>>                                                                              ^^^^^^^^^^^^^^^^^^^^^^
>> Dereference
>>
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  518                          dir1_type = FSNOTIFY_ITER_TYPE_PARENT;
>> 40a100d3adc1ad Amir Goldstein          2020-07-22  519          }
>> 497b0c5a7c0688 Amir Goldstein          2020-07-16  520
>> 7c49b8616460eb Dave Hansen             2015-09-04  521          /*
>> 7c49b8616460eb Dave Hansen             2015-09-04  522           * Optimization: srcu_read_lock() has a memory barrier which can
>> 7c49b8616460eb Dave Hansen             2015-09-04  523           * be expensive.  It protects walking the *_fsnotify_marks lists.
>> 7c49b8616460eb Dave Hansen             2015-09-04  524           * However, if we do not walk the lists, we do not have to do
>> 7c49b8616460eb Dave Hansen             2015-09-04  525           * SRCU because we have no references to any objects and do not
>> 7c49b8616460eb Dave Hansen             2015-09-04  526           * need SRCU to keep them "alive".
>> 7c49b8616460eb Dave Hansen             2015-09-04  527           */
>> 9b93f33105f5f9 Amir Goldstein          2020-07-16  528          if (!sb->s_fsnotify_marks &&
>> 497b0c5a7c0688 Amir Goldstein          2020-07-16  529              (!mnt || !mnt->mnt_fsnotify_marks) &&
>> 9b93f33105f5f9 Amir Goldstein          2020-07-16  530              (!inode || !inode->i_fsnotify_marks) &&
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  531              !dir1_type)
>> 7c49b8616460eb Dave Hansen             2015-09-04  532                  return 0;
>> 71d734103edfa2 Mel Gorman              2020-07-08  533
>> 9b93f33105f5f9 Amir Goldstein          2020-07-16  534          marks_mask = sb->s_fsnotify_mask;
>> 71d734103edfa2 Mel Gorman              2020-07-08  535          if (mnt)
>> 71d734103edfa2 Mel Gorman              2020-07-08  536                  marks_mask |= mnt->mnt_fsnotify_mask;
>> 9b93f33105f5f9 Amir Goldstein          2020-07-16  537          if (inode)
>> 9b93f33105f5f9 Amir Goldstein          2020-07-16  538                  marks_mask |= inode->i_fsnotify_mask;
>> d25f3ce8da49ce Amir Goldstein          2022-05-07  539          if (dir1_type) {
>> d25f3ce8da49ce Amir Goldstein          2022-05-07 @540                  if (dir1)
>>
>> If "dir1_type" is set then we have already dereferenced "dir1".  I guess
>> this unnecessary NULL check is something that probably wouldn't bother
>> a human reader too much...
> 
> True !!dir1_type means !!dir1.
> We could get rid of if (dir1)
> but I should note that I did not post this patch for review, this is an untested
> patch that I pushed to a branch on my private github.
> It is very generous of kbuild testbot to test any branch I push to my
> private github,
> but as much as I can recall, I never asked for it...

Hi Amir,

Sorry for the trouble, we'll only send the report to you privately.

Best Regards,
Rong Chen

> 
> Thanks,
> Amir.
> _______________________________________________
> kbuild-all mailing list -- kbuild-all@lists.01.org
> To unsubscribe send an email to kbuild-all-leave@lists.01.org
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2022-05-12  9:32 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-07 19:26 [amir73il:fsnotify-fixes 2/2] fs/notify/fsnotify.c:540 fsnotify() warn: variable dereferenced before check 'dir1' (see line 499) kernel test robot
2022-05-09 10:08 ` Dan Carpenter
2022-05-09 10:08 ` Dan Carpenter
2022-05-09 11:48 ` Amir Goldstein
2022-05-09 11:48   ` Amir Goldstein
2022-05-12  9:32   ` [kbuild-all] " Chen, Rong A

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