[SRU][Q][PATCH 1/1] ocfs2/dlm: fix off-by-one in dlm_match_regions() region comparison

[Cengiz Can]

From: Junrui Luo <moonafterrain at outlook.com>

The local-vs-remote region comparison loop uses '<=' instead of '<',
causing it to read one entry past the valid range of qr_regions.  The
other loops in the same function correctly use '<'.

Fix the loop condition to use '<' for consistency and correctness.

Link: https://lkml.kernel.org/r/SYBPR01MB78813DA26B50EC5E01F00566AF7BA@SYBPR01MB7881.ausprd01.prod.outlook.com
Fixes: ea2034416b54 ("ocfs2/dlm: Add message DLM_QUERY_REGION")
Signed-off-by: Junrui Luo <moonafterrain at outlook.com>
Reported-by: Yuhao Jiang <danisjiang at gmail.com>
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
Cc: Mark Fasheh <mark at fasheh.com>
Cc: Joel Becker <jlbec at evilplan.org>
Cc: Junxiao Bi <junxiao.bi at oracle.com>
Cc: Changwei Ge <gechangwei at live.cn>
Cc: Jun Piao <piaojun at huawei.com>
Cc: Heming Zhao <heming.zhao at suse.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
(cherry picked from commit 01b61e8dda9b0fdb0d4cda43de25f4e390554d7b)
CVE-2026-53309
Assisted-by: kybele:claude-opus-4.8
Signed-off-by: Cengiz Can <cengiz.can at canonical.com>
---
 fs/ocfs2/dlm/dlmdomain.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index 2018501b2249..de8982371d5f 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -994,7 +994,7 @@ static int dlm_match_regions(struct dlm_ctxt *dlm,
 	for (i = 0; i < localnr; ++i) {
 		foundit = 0;
 		r = remote;
-		for (j = 0; j <= qr->qr_numregions; ++j) {
+		for (j = 0; j < qr->qr_numregions; ++j) {
 			if (!memcmp(l, r, O2HB_MAX_REGION_NAME_LEN)) {
 				foundit = 1;
 				break;
-- 
2.43.0