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From: Dan Carpenter <dan.carpenter@linaro.org>
To: oe-kbuild@lists.linux.dev, Bharath SM <bharathsm.hsk@gmail.com>,
	linux-cifs@vger.kernel.org, smfrench@gmail.com, pc@manguebit.com,
	sprasad@microsoft.com, paul@darkrain42.org,
	henrique.carvalho@suse.com
Cc: lkp@intel.com, oe-kbuild-all@lists.linux.dev,
	Bharath SM <bharathsm@microsoft.com>
Subject: Re: [PATCH 2/2] smb: invalidate and close cached directory when creating child entries
Date: Wed, 2 Jul 2025 14:32:08 +0300	[thread overview]
Message-ID: <eebd401c-4e31-4282-af33-7dff1503c937@suswa.mountain> (raw)
In-Reply-To: <20250630185303.12087-1-bharathsm@microsoft.com>

Hi Bharath,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Bharath-SM/smb-invalidate-and-close-cached-directory-when-creating-child-entries/20250701-025420
base:   git://git.samba.org/sfrench/cifs-2.6.git for-next
patch link:    https://lore.kernel.org/r/20250630185303.12087-1-bharathsm%40microsoft.com
patch subject: [PATCH 2/2] smb: invalidate and close cached directory when creating child entries
config: i386-randconfig-141-20250702 (https://download.01.org/0day-ci/archive/20250702/202507021119.3IUZ9mSr-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0

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/202507021119.3IUZ9mSr-lkp@intel.com/

smatch warnings:
fs/smb/client/dir.c:361 cifs_do_create() warn: iterator used outside loop: 'parent_cfid'

vim +/parent_cfid +361 fs/smb/client/dir.c

67750fb9e07940 fs/cifs/dir.c       Jeff Layton       2008-05-09  310  	/*
67750fb9e07940 fs/cifs/dir.c       Jeff Layton       2008-05-09  311  	 * if we're not using unix extensions, see if we need to set
67750fb9e07940 fs/cifs/dir.c       Jeff Layton       2008-05-09  312  	 * ATTR_READONLY on the create call
67750fb9e07940 fs/cifs/dir.c       Jeff Layton       2008-05-09  313  	 */
f818dd55c4a8b3 fs/cifs/dir.c       Steve French      2009-01-19  314  	if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
67750fb9e07940 fs/cifs/dir.c       Jeff Layton       2008-05-09  315  		create_options |= CREATE_OPTION_READONLY;
67750fb9e07940 fs/cifs/dir.c       Jeff Layton       2008-05-09  316  
129f2ba6d160a9 fs/smb/client/dir.c Bharath SM        2025-07-01  317  
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  318  retry_open:
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  319  	if (tcon->cfids && direntry->d_parent && server->dialect >= SMB30_PROT_ID) {
129f2ba6d160a9 fs/smb/client/dir.c Bharath SM        2025-07-01  320  		parent_cfid = NULL;

This assignment should be removed because the parent_cfid pointer will
be set again inside the list_for_each_entry() loop.

037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  321  		spin_lock(&tcon->cfids->cfid_list_lock);
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  322  		list_for_each_entry(parent_cfid, &tcon->cfids->entries, entry) {
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  323  			if (parent_cfid->dentry == direntry->d_parent) {
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  324  				cifs_dbg(FYI, "found a parent cached file handle\n");
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  325  				if (parent_cfid->has_lease && parent_cfid->time) {
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  326  					lease_flags
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  327  						|= SMB2_LEASE_FLAG_PARENT_LEASE_KEY_SET_LE;
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  328  					memcpy(fid->parent_lease_key,
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  329  					       parent_cfid->fid.lease_key,
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  330  					       SMB2_LEASE_KEY_SIZE);
129f2ba6d160a9 fs/smb/client/dir.c Bharath SM        2025-07-01  331  					parent_cfid->dirents.is_valid = false;
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  332  				}
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  333  				break;
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  334  			}
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  335  		}

After the loop if we don't hit a break then parent_cfid will point to
invalid memory.  (It won't be NULL).

037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  336  		spin_unlock(&tcon->cfids->cfid_list_lock);
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  337  	}
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  338  
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  339  	oparms = (struct cifs_open_parms) {
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  340  		.tcon = tcon,
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  341  		.cifs_sb = cifs_sb,
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  342  		.desired_access = desired_access,
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  343  		.create_options = cifs_create_options(cifs_sb, create_options),
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  344  		.disposition = disposition,
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  345  		.path = full_path,
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  346  		.fid = fid,
037e1bae588eac fs/smb/client/dir.c Henrique Carvalho 2025-05-28  347  		.lease_flags = lease_flags,
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  348  		.mode = mode,
de036dcaca65cf fs/cifs/dir.c       Volker Lendecke   2023-01-11  349  	};
226730b4d8adae fs/cifs/dir.c       Pavel Shilovsky   2013-07-05  350  	rc = server->ops->open(xid, &oparms, oplock, buf);
^1da177e4c3f41 fs/cifs/dir.c       Linus Torvalds    2005-04-16  351  	if (rc) {
f96637be081141 fs/cifs/dir.c       Joe Perches       2013-05-04  352  		cifs_dbg(FYI, "cifs_create returned 0x%x\n", rc);
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  353  		if (rc == -EACCES && rdwr_for_fscache == 1) {
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  354  			desired_access &= ~GENERIC_READ;
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  355  			rdwr_for_fscache = 2;
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  356  			goto retry_open;
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  357  		}
d2c127197dfc0b fs/cifs/dir.c       Miklos Szeredi    2012-06-05  358  		goto out;
c3b2a0c640bff7 fs/cifs/dir.c       Steve French      2009-02-20  359  	}
129f2ba6d160a9 fs/smb/client/dir.c Bharath SM        2025-07-01  360  
129f2ba6d160a9 fs/smb/client/dir.c Bharath SM        2025-07-01 @361  	if (parent_cfid && !parent_cfid->dirents.is_valid)
                                                                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
So this check is reading from invalid memory.

129f2ba6d160a9 fs/smb/client/dir.c Bharath SM        2025-07-01  362  		close_cached_dir(parent_cfid);
129f2ba6d160a9 fs/smb/client/dir.c Bharath SM        2025-07-01  363  
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  364  	if (rdwr_for_fscache == 2)
e9e62243a3e232 fs/smb/client/dir.c David Howells     2024-04-02  365  		cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);
c3b2a0c640bff7 fs/cifs/dir.c       Steve French      2009-02-20  366  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki


  reply	other threads:[~2025-07-02 11:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-30 18:53 [PATCH 2/2] smb: invalidate and close cached directory when creating child entries Bharath SM
2025-07-02 11:32 ` Dan Carpenter [this message]
2025-07-02 16:55 ` Henrique Carvalho
2025-07-02 20:31   ` Enzo Matsumiya
2025-07-03  5:55     ` Steve French

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