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authorUlrich Drepper <drepper@redhat.com>2005-09-27 05:45:26 +0000
committerUlrich Drepper <drepper@redhat.com>2005-09-27 05:45:26 +0000
commit7dac9f3d90fc108d2db8e305f6d3d475b6c5b793 (patch)
tree596c71b8a2292d99f8d98ff44997a1ea86881c9c /malloc/arena.c
parent2e79fa3ebcdadd4df5d04aa74aed20213f7021f0 (diff)
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[BZ #838]
* malloc/arena.c (ptmalloc_lock_all): If global lock already taken by the same thread, just bump the counter. (ptmalloc_unlock_all): If counter for recursive locks hasn't reached zero, don't do anything else. * malloc/Makefile (tests): Add tst-mallocfork. * malloc/tst-mallocfork.c: New file.
Diffstat (limited to 'malloc/arena.c')
-rw-r--r--malloc/arena.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/malloc/arena.c b/malloc/arena.c
index 8db255966d..a844392a6b 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -210,6 +210,10 @@ free_atfork(Void_t* mem, const Void_t *caller)
(void)mutex_unlock(&ar_ptr->mutex);
}
+
+/* Counter for number of times the list is locked by the same thread. */
+static unsigned int atfork_recursive_cntr;
+
/* The following two functions are registered via thread_atfork() to
make sure that the mutexes remain in a consistent state in the
fork()ed version of a thread. Also adapt the malloc and free hooks
@@ -223,7 +227,18 @@ ptmalloc_lock_all (void)
if(__malloc_initialized < 1)
return;
- (void)mutex_lock(&list_lock);
+ if (mutex_trylock(&list_lock))
+ {
+ Void_t *my_arena;
+ tsd_getspecific(arena_key, my_arena);
+ if (my_arena == ATFORK_ARENA_PTR)
+ /* This is the same thread which already locks the global list.
+ Just bump the counter. */
+ goto out;
+
+ /* This thread has to wait its turn. */
+ (void)mutex_lock(&list_lock);
+ }
for(ar_ptr = &main_arena;;) {
(void)mutex_lock(&ar_ptr->mutex);
ar_ptr = ar_ptr->next;
@@ -236,6 +251,8 @@ ptmalloc_lock_all (void)
/* Only the current thread may perform malloc/free calls now. */
tsd_getspecific(arena_key, save_arena);
tsd_setspecific(arena_key, ATFORK_ARENA_PTR);
+ out:
+ ++atfork_recursive_cntr;
}
static void
@@ -245,6 +262,8 @@ ptmalloc_unlock_all (void)
if(__malloc_initialized < 1)
return;
+ if (--atfork_recursive_cntr != 0)
+ return;
tsd_setspecific(arena_key, save_arena);
__malloc_hook = save_malloc_hook;
__free_hook = save_free_hook;