Segfault with 1 arena through `mi_manage_os_memory_ex` and multiple per-thread heaps through `mi_heap_new_in_arena`

[MIvanchev]

I get the following stacktrace when using a single arena like that

    mi_option_enable(mi_option_verbose);
    mi_option_enable(mi_option_show_errors);

    if(_not(mi_manage_os_memory_ex(
                 mem,
                 MEM_ARENA_SIZE,
                 true, // commited
                 false,
                 true, // zero
                 -1,
                 true,
                 &arena
             ))) {
        print_err("Failed to initialize mimalloc (a memory allocator).");
        exit(1);
    }

   // Per thread

   static __thread mi_heap_t *g_threadHeap;
   g_threadHeap = mi_heap_new_in_arena(arena);

   // Alloc

   ret = mi_heap_realloc(g_threadHeap, ptr, newSize);

0xf7f5058f ???
	???:0
0x820b128 mi_segment_os_alloc
	src/3rdparty/mimalloc-main/src/segment.c:863
0x820b128 mi_segment_alloc
	src/3rdparty/mimalloc-main/src/segment.c:925
0x820d5a5 mi_segment_reclaim_or_alloc
	src/3rdparty/mimalloc-main/src/segment.c:1541
0x820d5a5 mi_segments_page_alloc
	src/3rdparty/mimalloc-main/src/segment.c:1560
0x820da5f _mi_segment_page_alloc
	src/3rdparty/mimalloc-main/src/segment.c:1671
0x820db35 mi_page_fresh_alloc
	src/3rdparty/mimalloc-main/src/page.c:309
0x820e2d1 mi_page_fresh
	src/3rdparty/mimalloc-main/src/page.c:333
0x820e2d1 mi_page_queue_find_free_ex
	src/3rdparty/mimalloc-main/src/page.c:868
0x820e959 _mi_malloc_generic
	src/3rdparty/mimalloc-main/src/page.c:1051
0x820fbc9 mi_heap_malloc_small_zero
	src/3rdparty/mimalloc-main/src/alloc.c:147
0x820fbc9 _mi_heap_malloc_zero_ex
	src/3rdparty/mimalloc-main/src/alloc.c:176
0x821338b mi_heap_umalloc
	src/3rdparty/mimalloc-main/src/alloc.c:241
0x821338b _mi_heap_realloc_zero
	src/3rdparty/mimalloc-main/src/alloc.c:308
0x8213569 mi_heap_realloc
	src/3rdparty/mimalloc-main/src/alloc.c:329

Can someone tell me what I am doing wrong or if this is a bug? The program WORKS with the debug flags (no optimizations etc.). I am using the latest main revision.

[MIvanchev]

The library is compiled statically through static.c

[MIvanchev]

So the error happens if I compile with -O2 at which point the a huge number of warnings is emitted

src/3rdparty/mimalloc-main/include/mimalloc/internal.h:640:28: warning: inlining failed in call to 'mi_tf_delayed': function not inlinable [-Winline]
  640 | static inline mi_delayed_t mi_tf_delayed(mi_thread_free_t tf) {

[MIvanchev]

-O1 is the maximum the lib will work with it seems. This is 32-bit x86.

[daanx]

Very strange -- I wonder if there is some 32-bit or compiler issue since mi_tf_delayed is a single logical and and it should be inlineable otherwise. What is the C compiler + version ? What is the OS? The crash is also in a strange location so not sure what is happening.

[MIvanchev]

@daanx this is VoidLinux, gcc (GCC) 14.2.1 20250405. It appears that at -O2 the symbol mi_segment_calculate_slices is unresolvable on some threads. It works on the main and another one, but the 3rd fails. Again, only with '-O2'. no-inline has no effect.