linux-kernel - [PATCH next] liveupdate: luo_file: don't use invalid list iterator

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Message-ID: <aSlMc4SS09Re4_xn@stanley.mountain>
Date: Fri, 28 Nov 2025 10:17:07 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Pasha Tatashin <pasha.tatashin@...een.com>
Cc: Mike Rapoport <rppt@...nel.org>, Pratyush Yadav <pratyush@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH next] liveupdate: luo_file: don't use invalid list iterator

If we exit a list_for_each_entry() without hitting a break then the
list iterator points to an offset from the list_head.  It's a
non-NULL but invalid pointer and dereferencing it isn't allowed.

Introduce a new "found" variable to test instead.

Fixes: 3ee1d673194e ("liveupdate: luo_file: implement file systems callbacks")
Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/r/202511280420.y9O4fyhX-lkp@intel.com/
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
Presumably, this going to be folded into the original patch.  I just
added the tags because they are harmless.

 kernel/liveupdate/luo_file.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c
index fca3806dae28..86b4d274d9aa 100644
--- a/kernel/liveupdate/luo_file.c
+++ b/kernel/liveupdate/luo_file.c
@@ -561,17 +561,20 @@ int luo_retrieve_file(struct luo_file_set *file_set, u64 token,
 {
 	struct liveupdate_file_op_args args = {0};
 	struct luo_file *luo_file;
+	bool found = false;
 	int err;
 
 	if (list_empty(&file_set->files_list))
 		return -ENOENT;
 
 	list_for_each_entry(luo_file, &file_set->files_list, list) {
-		if (luo_file->token == token)
+		if (luo_file->token == token) {
+			found = true;
 			break;
+		}
 	}
 
-	if (luo_file->token != token)
+	if (!found)
 		return -ENOENT;
 
 	guard(mutex)(&luo_file->mutex);
-- 
2.51.0