kernel/liveupdate/luo_file.c:558:5-13: ERROR: invalid reference to the index variable of the iterator on line 553 (fwd)

kernel/liveupdate/luo_file.c:558:5-13: ERROR: invalid reference to the index variable of the iterator on line 553 (fwd)

[Julia Lawall]

luo_file may point to something random if the break in the
list_for_each_entry is not taken.

julia

---------- Forwarded message ----------
Date: Mon, 02 Nov 2026 00:06:55 +0100
From: kernel test robot <lkp@intel.com>
To: oe-kbuild@lists.linux.dev
Cc: lkp@intel.com, Julia Lawall <julia.lawall@inria.fr>
Subject: kernel/liveupdate/luo_file.c:558:5-13: ERROR: invalid reference to the
    index variable of the iterator on line 553

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: linux-kernel@vger.kernel.org
TO: Pasha Tatashin <pasha.tatashin@soleen.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linux Memory Management List <linux-mm@kvack.org>
CC: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
CC: Pratyush Yadav <pratyush@kernel.org>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   6628e7d4c6b25c8d18f1345e3a20d21829aae7e4
commit: 7c722a7f44e0c1f9714084152226bc7bd644b7e3 liveupdate: luo_file: implement file systems callbacks
date:   11 months ago
:::::: branch date: 2 hours ago
:::::: commit date: 11 months ago
config: x86_64-randconfig-2103-20261101 (https://download.01.org/0day-ci/archive/20261101/202611012349.RESCKElP-lkp@intel.com/config)
compiler: clang version 22.1.8 (https://github.com/llvm/llvm-project ca7933e47d3a3451d81e72ac174dcb5aa28b59d1)

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
| Fixes: 7c722a7f44e0 ("liveupdate: luo_file: implement file systems callbacks")
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Julia Lawall <julia.lawall@inria.fr>
| Closes: https://lore.kernel.org/r/202611012349.RESCKElP-lkp@intel.com/

cocci warnings: (new ones prefixed by >>)
>> kernel/liveupdate/luo_file.c:558:5-13: ERROR: invalid reference to the index variable of the iterator on line 553

vim +558 kernel/liveupdate/luo_file.c

7c722a7f44e0c1 Pasha Tatashin 2025-11-25  517
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  518  /**
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  519   * luo_retrieve_file - Restores a preserved file from a file_set by its token.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  520   * @file_set: The file_set from which to retrieve the file.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  521   * @token:    The unique token identifying the file to be restored.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  522   * @filep:    Output parameter; on success, this is populated with a pointer
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  523   *            to the newly retrieved 'struct file'.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  524   *
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  525   * This function is the primary mechanism for recreating a file in the new
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  526   * kernel after a live update. It searches the file_set's list of deserialized
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  527   * files for an entry matching the provided @token.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  528   *
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  529   * The operation is idempotent: if a file has already been successfully
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  530   * retrieved, this function will simply return a pointer to the existing
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  531   * 'struct file' and report success without re-executing the retrieve
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  532   * operation. This is handled by checking the 'retrieved' flag under a lock.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  533   *
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  534   * File retrieval can happen in any order; it is not bound by the order of
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  535   * preservation.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  536   *
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  537   * Context: Can be called from an ioctl or other in-kernel code in the new
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  538   *          kernel.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  539   * Return: 0 on success. Returns a negative errno on failure:
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  540   *         -ENOENT if no file with the matching token is found.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  541   *         Any error code returned by the handler's .retrieve() op.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  542   */
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  543  int luo_retrieve_file(struct luo_file_set *file_set, u64 token,
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  544  		      struct file **filep)
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  545  {
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  546  	struct liveupdate_file_op_args args = {0};
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  547  	struct luo_file *luo_file;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  548  	int err;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  549
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  550  	if (list_empty(&file_set->files_list))
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  551  		return -ENOENT;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  552
7c722a7f44e0c1 Pasha Tatashin 2025-11-25 @553  	list_for_each_entry(luo_file, &file_set->files_list, list) {
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  554  		if (luo_file->token == token)
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  555  			break;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  556  	}
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  557
7c722a7f44e0c1 Pasha Tatashin 2025-11-25 @558  	if (luo_file->token != token)
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  559  		return -ENOENT;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  560
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  561  	guard(mutex)(&luo_file->mutex);
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  562  	if (luo_file->retrieved) {
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  563  		/*
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  564  		 * Someone is asking for this file again, so get a reference
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  565  		 * for them.
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  566  		 */
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  567  		get_file(luo_file->file);
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  568  		*filep = luo_file->file;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  569  		return 0;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  570  	}
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  571
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  572  	args.handler = luo_file->fh;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  573  	args.serialized_data = luo_file->serialized_data;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  574  	err = luo_file->fh->ops->retrieve(&args);
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  575  	if (!err) {
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  576  		luo_file->file = args.file;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  577
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  578  		/* Get reference so we can keep this file in LUO until finish */
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  579  		get_file(luo_file->file);
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  580  		*filep = luo_file->file;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  581  		luo_file->retrieved = true;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  582  	}
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  583
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  584  	return err;
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  585  }
7c722a7f44e0c1 Pasha Tatashin 2025-11-25  586

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Re: kernel/liveupdate/luo_file.c:558:5-13: ERROR: invalid reference to the index variable of the iterator on line 553 (fwd)

[Pratyush Yadav]

Hi Julia,

On Mon, Nov 02 2026, Julia Lawall wrote:

> luo_file may point to something random if the break in the
> list_for_each_entry is not taken.

This was fixed almost a year ago by b2135d1cb0e36 ("liveupdate:
luo_file: don't use invalid list iterator").

Perhaps check why the bot is looking at old commits?

[...]

-- 
Regards,
Pratyush Yadav