MUTANT (CI only): realloc copies half the shared prefix - the fuzz test must fail

Author: Lt-Flash

.github/workflows/unittests.yml

@@ -43,64 +43,10 @@ jobs:
 
     strategy:
       fail-fast: false
+      # MUTANT branch (CI only): one native job is enough to show the tests fail
       matrix:
-        os: [20.04, 22.04, 24.04, 26.04]
-        compiler: ['gcc', 'clang']
-        include:
-          - os: 20.04
-            compiler: 'gcc-9'
-          - os: 20.04
-            compiler: 'gcc-10'
-          - os: 20.04
-            compiler: 'clang-9'
-          - os: 20.04
-            compiler: 'clang-10'
-          - os: 24.04
-            compiler: 'gcc'
-          - os: 24.04
-            compiler: 'clang'
-          - os: 24.04
-            compiler: 'gcc-13'
-          - os: 24.04
-            compiler: 'gcc-14'
-          - os: 24.04
-            compiler: 'clang-16'
-          - os: 24.04
-            compiler: 'clang-17'
-          - os: 24.04
-            compiler: 'clang-18'
-          - os: 24.04
-            compiler: 'clang-19'
-          - os: 22.04
-            compiler: 'gcc-11'
-          - os: 22.04
-            compiler: 'gcc-12'
-          - os: 22.04
-            compiler: 'clang-11'
-          - os: 22.04
-            compiler: 'clang-12'
-          - os: 22.04
-            compiler: 'clang-13'
-          - os: 22.04
-            compiler: 'clang-14'
-          - os: 22.04
-            compiler: 'clang-15'
-          - os: 22.04
-            compiler: 'gcc-arm64-qemu-cross'
-          - os: 22.04
-            compiler: 'gcc-arm32-qemu-cross'
-          - os: 22.04
-            compiler: 'clang-arm64-qemu-cross'
-          - os: 22.04
-            compiler: 'clang-arm32-qemu-cross'
-          - os: 26.04
-            compiler: 'gcc-14'
-          - os: 26.04
-            compiler: 'clang-18'
-          - os: 26.04
-            compiler: 'clang-19'
-          - os: 26.04
-            compiler: 'clang-20'
+        os: [24.04]
+        compiler: ['gcc']
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:

mem/hg_malloc_dyn.h

@@ -232,6 +232,7 @@ void *hg_realloc(struct hg_block *hb, void *p, unsigned long size,
 			if (own)
 				hg_san_open(own, HG_HDR(p), cur_payload);
 		}
+		copy /= 2;      /* MUTANT: realloc keeps half the shared prefix */
 		memcpy(ptr, p, copy);
 		#if !defined INLINE_ALLOC && defined DBG_MALLOC
 		hg_free_dbg(hb, p, file, func, line);