malloc: Improve malloc initialization

Move malloc initialization to __libc_early_init.  Use a hidden __ptmalloc_init
for initialization and a weak call to avoid pulling in the system malloc in a
static binary.  All previous initialization checks can now be removed.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

elf/libc_early_init.c

@@ -24,6 +24,7 @@
 #include <pthread_early_init.h>
 #include <sys/single_threaded.h>
 #include <getrandom-internal.h>
+#include <malloc/malloc-internal.h>
 
 #ifdef SHARED
 _Bool __libc_initial;
@@ -32,6 +33,9 @@ _Bool __libc_initial;
 void
 __libc_early_init (_Bool initial)
 {
+  /* Initialize system malloc.  */
+  call_function_static_weak (__ptmalloc_init);
+
   /* Initialize ctype data.  */
   __ctype_init ();
 

malloc/arena.c

@@ -113,9 +113,6 @@ static mstate free_list;
    acquired.  */
 __libc_lock_define_initialized (static, list_lock);
 
-/* Already initialized? */
-static bool __malloc_initialized = false;
-
 /**************************************************************************/
 
 
@@ -168,9 +165,6 @@ arena_for_chunk (mchunkptr ptr)
 void
 __malloc_fork_lock_parent (void)
 {
-  if (!__malloc_initialized)
-    return;
-
   /* We do not acquire free_list_lock here because we completely
      reconstruct free_list in __malloc_fork_unlock_child.  */
 
@@ -188,9 +182,6 @@ __malloc_fork_lock_parent (void)
 void
 __malloc_fork_unlock_parent (void)
 {
-  if (!__malloc_initialized)
-    return;
-
   for (mstate ar_ptr = &main_arena;; )
     {
       __libc_lock_unlock (ar_ptr->mutex);
@@ -204,9 +195,6 @@ __malloc_fork_unlock_parent (void)
 void
 __malloc_fork_unlock_child (void)
 {
-  if (!__malloc_initialized)
-    return;
-
   /* Push all arenas to the free list, except thread_arena, which is
      attached to the current thread.  */
   __libc_lock_init (free_list_lock);
@@ -259,14 +247,9 @@ TUNABLE_CALLBACK_FNDECL (set_hugetlb, size_t)
 static void tcache_key_initialize (void);
 #endif
 
-static void
+void
-ptmalloc_init (void)
+__ptmalloc_init (void)
 {
-  if (__malloc_initialized)
-    return;
-
-  __malloc_initialized = true;
-
 #if USE_TCACHE
   tcache_key_initialize ();
 #endif

malloc/malloc-check.c

@@ -389,7 +389,7 @@ initialize_malloc_check (void)
 {
   /* This is the copy of the malloc initializer that we pulled in along with
      malloc-check.  This does not affect any of the libc malloc structures.  */
-  ptmalloc_init ();
+  __ptmalloc_init ();
   TUNABLE_GET (check, int32_t, TUNABLE_CALLBACK (set_mallopt_check));
   return __is_malloc_debug_enabled (MALLOC_CHECK_HOOK);
 }

malloc/malloc-internal.h

@@ -40,4 +40,7 @@ void __malloc_arena_thread_freeres (void) attribute_hidden;
 /* Activate a standard set of debugging hooks. */
 void __malloc_check_init (void) attribute_hidden;
 
+/* Initialize malloc.  */
+void __ptmalloc_init (void) attribute_hidden;
+
 #endif /* _MALLOC_INTERNAL_H */

malloc/malloc.c

@@ -1937,7 +1937,7 @@ static struct malloc_par mp_ =
 /*
    Initialize a malloc_state struct.
 
-   This is called from ptmalloc_init () or from _int_new_arena ()
+   This is called from __ptmalloc_init () or from _int_new_arena ()
    when creating a new arena.
  */
 
@@ -3347,9 +3347,6 @@ __libc_malloc2 (size_t bytes)
   mstate ar_ptr;
   void *victim;
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   MAYBE_INIT_TCACHE ();
 
   if (SINGLE_THREAD_P)
@@ -3455,9 +3452,6 @@ __libc_realloc (void *oldmem, size_t bytes)
 
   void *newp;             /* chunk to return */
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
 #if REALLOC_ZERO_BYTES_FREES
   if (bytes == 0 && oldmem != NULL)
     {
@@ -3583,9 +3577,6 @@ libc_hidden_def (__libc_realloc)
 void *
 __libc_memalign (size_t alignment, size_t bytes)
 {
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   void *address = RETURN_ADDRESS (0);
   return _mid_memalign (alignment, bytes, address);
 }
@@ -3596,9 +3587,6 @@ void *
 weak_function
 aligned_alloc (size_t alignment, size_t bytes)
 {
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
 /* Similar to memalign, but starting with ISO C17 the standard
    requires an error for alignments that are not supported by the
    implementation.  Valid alignments for the current implementation
@@ -3698,9 +3686,6 @@ _mid_memalign (size_t alignment, size_t bytes, void *address)
 void *
 __libc_valloc (size_t bytes)
 {
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   void *address = RETURN_ADDRESS (0);
   size_t pagesize = GLRO (dl_pagesize);
   return _mid_memalign (pagesize, bytes, address);
@@ -3709,9 +3694,6 @@ __libc_valloc (size_t bytes)
 void *
 __libc_pvalloc (size_t bytes)
 {
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   void *address = RETURN_ADDRESS (0);
   size_t pagesize = GLRO (dl_pagesize);
   size_t rounded_bytes;
@@ -3746,9 +3728,6 @@ __libc_calloc (size_t n, size_t elem_size)
 
   sz = bytes;
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
 #if USE_TCACHE
   size_t tc_idx = usize2tidx (bytes);
   if (tcache_available (tc_idx))
@@ -5211,9 +5190,6 @@ __malloc_trim (size_t s)
 {
   int result = 0;
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   mstate ar_ptr = &main_arena;
   do
     {
@@ -5330,9 +5306,6 @@ __libc_mallinfo2 (void)
   struct mallinfo2 m;
   mstate ar_ptr;
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   memset (&m, 0, sizeof (m));
   ar_ptr = &main_arena;
   do
@@ -5381,8 +5354,6 @@ __malloc_stats (void)
   mstate ar_ptr;
   unsigned int in_use_b = mp_.mmapped_mem, system_b = in_use_b;
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
   _IO_flockfile (stderr);
   int old_flags2 = stderr->_flags2;
   stderr->_flags2 |= _IO_FLAGS2_NOTCANCEL;
@@ -5563,8 +5534,6 @@ __libc_mallopt (int param_number, int value)
   mstate av = &main_arena;
   int res = 1;
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
   __libc_lock_lock (av->mutex);
 
   LIBC_PROBE (memory_mallopt, 2, param_number, value);
@@ -5780,11 +5749,14 @@ malloc_printerr (const char *str)
 }
 
 #if USE_TCACHE
+
+static volatile int dummy_var;
+
 static __attribute_noinline__ void
 malloc_printerr_tail (const char *str)
 {
   /* Ensure this cannot be a no-return function.  */
-  if (!__malloc_initialized)
+  if (dummy_var)
     return;
   malloc_printerr (str);
 }
@@ -5797,9 +5769,6 @@ __posix_memalign (void **memptr, size_t alignment, size_t size)
 {
   void *mem;
 
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   /* Test whether the SIZE argument is valid.  It must be a power of
      two multiple of sizeof (void *).  */
   if (alignment % sizeof (void *) != 0
@@ -5840,11 +5809,6 @@ __malloc_info (int options, FILE *fp)
   size_t total_aspace = 0;
   size_t total_aspace_mprotect = 0;
 
-
-
-  if (!__malloc_initialized)
-    ptmalloc_init ();
-
   fputs ("<malloc version=\"1\">\n", fp);
 
   /* Iterate over all arenas currently in use.  */