diff options
Diffstat (limited to 'lib/libc/stdlib/malloc.c')
| -rw-r--r-- | lib/libc/stdlib/malloc.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c index 86c22fe..a765af9 100644 --- a/lib/libc/stdlib/malloc.c +++ b/lib/libc/stdlib/malloc.c @@ -350,8 +350,12 @@ typedef struct { spinlock_t lock; } malloc_mutex_t; +/* Set to true once the allocator has been initialized. */ static bool malloc_initialized = false; +/* Used to avoid initialization races. */ +static malloc_mutex_t init_lock = {_SPINLOCK_INITIALIZER}; + /******************************************************************************/ /* * Statistics data structures. @@ -2969,12 +2973,6 @@ static inline bool malloc_init(void) { - /* - * We always initialize before threads are created, since any thread - * creation first triggers allocations. - */ - assert(__isthreaded == 0 || malloc_initialized); - if (malloc_initialized == false) return (malloc_init_hard()); @@ -2989,6 +2987,16 @@ malloc_init_hard(void) char buf[PATH_MAX + 1]; const char *opts; + malloc_mutex_lock(&init_lock); + if (malloc_initialized) { + /* + * Another thread initialized the allocator before this one + * acquired init_lock. + */ + malloc_mutex_unlock(&init_lock); + return (false); + } + /* Get number of CPUs. */ { int mib[2]; @@ -3339,8 +3347,10 @@ malloc_init_hard(void) /* Allocate and initialize arenas. */ arenas = (arena_t **)base_alloc(sizeof(arena_t *) * narenas); - if (arenas == NULL) + if (arenas == NULL) { + malloc_mutex_unlock(&init_lock); return (true); + } /* * Zero the array. In practice, this should always be pre-zeroed, * since it was just mmap()ed, but let's be sure. @@ -3352,12 +3362,15 @@ malloc_init_hard(void) * arena_choose_hard(). */ arenas_extend(0); - if (arenas[0] == NULL) + if (arenas[0] == NULL) { + malloc_mutex_unlock(&init_lock); return (true); + } malloc_mutex_init(&arenas_mtx); malloc_initialized = true; + malloc_mutex_unlock(&init_lock); return (false); } |
