From 2311cd785ae875965a77d848d3f6ee29258fa0fe Mon Sep 17 00:00:00 2001
From: Daimiao Chen <daimiao.chen@accuenergy.com>
Date: Thu, 22 Jan 2026 11:04:59 -0500
Subject: [PATCH] Guard null callbacks in lfs_dir_fetchmatch
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lfs_dir_fetch relies on an impossible tag match to avoid calling a
NULL callback. Add an explicit cb != NULL check in the match path
so future refactors don’t risk a NULL function-pointer call.
---
 lfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lfs.c b/lfs.c
index da4bfca4..fce9d3bf 100644
--- a/lfs.c
+++ b/lfs.c
@@ -1290,7 +1290,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
             }
 
             // found a match for our fetcher?
-            if ((fmask & tag) == (fmask & ftag)) {
+            if ((fmask & tag) == (fmask & ftag) && (cb != NULL)) {
                 int res = cb(data, tag, &(struct lfs_diskoff){
                         dir->pair[0], off+sizeof(tag)});
                 if (res < 0) {