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fix GC bug

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This is a variant of the bug fixed in
49fbca5b18,
where a GC-notification callback still
could cause problems in a GC during a finalization
callback.

(Bug found by running tests in GC-stress mode.)
This commit is contained in:
Matthew Flatt 2013-07-06 07:21:46 -06:00
parent d618a8d616
commit 4266e606e3
5 changed files with 47 additions and 26 deletions
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1
racket/src/racket/gc2/fnls.c
View File

@ -67,6 +67,7 @@ void GC_set_finalizer(void *p, int tagged, int level, void (*f)(void *p, void *d
return;
/* Allcation might trigger GC, so we use park: */
CHECK_PARK_UNUSED(gc);
gc->park[0] = p;
gc->park[1] = data;

2
racket/src/racket/gc2/mem_account.c
View File

@ -248,6 +248,7 @@ inline static uintptr_t custodian_usage(NewGC*gc, void *custodian)
if(!gc->really_doing_accounting) {
if (!gc->dumping_avoid_collection) {
CHECK_PARK_UNUSED(gc);
gc->park[0] = custodian;
gc->really_doing_accounting = 1;
garbage_collect(gc, 1, 0, NULL);
@ -502,6 +503,7 @@ inline static void BTC_add_account_hook(int type,void *c1,void *c2,uintptr_t b)
if(!gc->really_doing_accounting) {
if (!gc->dumping_avoid_collection) {
CHECK_PARK_UNUSED(gc);
gc->park[0] = c1;
gc->park[1] = c2;
gc->really_doing_accounting = 1;

64
racket/src/racket/gc2/newgc.c
View File

@ -87,6 +87,8 @@ intptr_t mp_ac_freed;
# define GC_LOCK_DEBUG(args) /* empty */
#endif
#define CHECK_PARK_UNUSED(gc) GC_ASSERT(!gc->park[0])
/* the page type constants */
enum {
PAGE_TAGGED = 0,
@ -350,9 +352,7 @@ inline static void check_used_against_max(NewGC *gc, size_t len)
page_count = size_to_apage_count(len);
gc->used_pages += page_count;
#if MZ_GC_BACKTRACE
if (gc->dumping_avoid_collection) return;
#endif
if(gc->in_unsafe_allocation_mode) {
if(gc->used_pages > gc->max_pages_in_heap)
@ -1215,7 +1215,7 @@ inline static void gen0_free_mpage(NewGC *gc, mpage *page) {
#ifdef MZ_GC_STRESS_TESTING
# define GC_TRIGGER_COUNT 100
static int stress_counter = 0;
int scheme_gc_slow_path_started = 0;
int scheme_gc_slow_path_started = 1;
static int TAKE_SLOW_PATH()
{
if (!scheme_gc_slow_path_started) return 0;
@ -1422,6 +1422,7 @@ void *GC_malloc_pair(void *car, void *cdr)
if (TAKE_SLOW_PATH() || OVERFLOWS_GEN0(newptr)) {
NewGC *gc = GC_get_GC();
CHECK_PARK_UNUSED(gc);
gc->park[0] = car;
gc->park[1] = cdr;
pair = allocate(sizeof(Scheme_Simple_Object), PAGE_PAIR);
@ -2855,7 +2856,8 @@ static NewGC *init_type_tags_worker(NewGC *inheritgc, NewGC *parentgc,
}
initialize_signal_handler(gc);
GC_add_roots(&gc->park, (char *)&gc->park + sizeof(gc->park) + 1);
GC_add_roots(&gc->park_save, (char *)&gc->park_save + sizeof(gc->park_save) + 1);
GC_add_roots(&gc->park_fsave, (char *)&gc->park_fsave + sizeof(gc->park_fsave) + 1);
GC_add_roots(&gc->park_isave, (char *)&gc->park_isave + sizeof(gc->park_isave) + 1);
return gc;
}
@ -4569,6 +4571,29 @@ void print_debug_stats(NewGC *gc) {
}
#endif
static void park_for_inform_callback(NewGC *gc)
{
/* Avoid nested collections, which would need
nested parking spaces: */
gc->dumping_avoid_collection++;
/* Inform might allocate, which might need park: */
gc->park_isave[0] = gc->park[0];
gc->park_isave[1] = gc->park[1];
gc->park[0] = NULL;
gc->park[1] = NULL;
}
static void unpark_for_inform_callback(NewGC *gc)
{
gc->park[0] = gc->park_isave[0];
gc->park[1] = gc->park_isave[1];
gc->park_isave[0] = NULL;
gc->park_isave[1] = NULL;
--gc->dumping_avoid_collection;
}
#if 0
extern double scheme_get_inexact_milliseconds(void);
# define TIME_DECLS() double start, task_start
@ -4813,25 +4838,12 @@ static void garbage_collect(NewGC *gc, int force_full, int switching_master, Log
#ifdef MZ_USE_PLACES
is_master = (gc == MASTERGC);
#endif
gc->dumping_avoid_collection++;
/* Inform might allocate, which might need park: */
gc->park_save[0] = gc->park[0];
gc->park_save[1] = gc->park[1];
gc->park[0] = NULL;
gc->park[1] = NULL;
park_for_inform_callback(gc);
gc->GC_collect_inform_callback(is_master, gc->gc_full,
old_mem_use + old_gen0, gc->memory_in_use,
old_mem_allocated, mmu_memory_allocated(gc->mmu),
gc->child_gc_total);
gc->park[0] = gc->park_save[0];
gc->park[1] = gc->park_save[1];
gc->park_save[0] = NULL;
gc->park_save[1] = NULL;
--gc->dumping_avoid_collection;
unpark_for_inform_callback(gc);
}
#ifdef MZ_USE_PLACES
if (lmi) {
@ -4863,8 +4875,8 @@ static void garbage_collect(NewGC *gc, int force_full, int switching_master, Log
gc->running_finalizers = 1;
/* Finalization might allocate, which might need park: */
gc->park_save[0] = gc->park[0];
gc->park_save[1] = gc->park[1];
gc->park_fsave[0] = gc->park[0];
gc->park_fsave[1] = gc->park[1];
gc->park[0] = NULL;
gc->park[1] = NULL;
@ -4885,10 +4897,10 @@ static void garbage_collect(NewGC *gc, int force_full, int switching_master, Log
#endif
gc->running_finalizers = 0;
gc->park[0] = gc->park_save[0];
gc->park[1] = gc->park_save[1];
gc->park_save[0] = NULL;
gc->park_save[1] = NULL;
gc->park[0] = gc->park_fsave[0];
gc->park[1] = gc->park_fsave[1];
gc->park_fsave[0] = NULL;
gc->park_fsave[1] = NULL;
} else
next_gc_full = 0;
@ -4905,10 +4917,12 @@ static void garbage_collect(NewGC *gc, int force_full, int switching_master, Log
wait_if_master_in_progress(gc, &sub_lmi);
if (sub_lmi.ran) {
if (gc->GC_collect_inform_callback) {
park_for_inform_callback(gc);
gc->GC_collect_inform_callback(1, sub_lmi.full,
sub_lmi.pre_used, sub_lmi.post_used,
sub_lmi.pre_admin, sub_lmi.post_admin,
0);
unpark_for_inform_callback(gc);
}
}
}

3
racket/src/racket/gc2/newgc.h
View File

@ -225,7 +225,8 @@ typedef struct NewGC {
int num_fnls;
void *park[2];
void *park_save[2];
void *park_fsave[2];
void *park_isave[2];
unsigned short weak_array_tag;
unsigned short weak_box_tag;

3
racket/src/racket/gc2/weak.c
View File

@ -87,6 +87,7 @@ void *GC_malloc_weak_array(size_t size_in_bytes, void *replace_val)
GC_Weak_Array *w;
/* Allcation might trigger GC, so we use park: */
CHECK_PARK_UNUSED(gc);
gc->park[0] = replace_val;
w = (GC_Weak_Array *)GC_malloc_one_tagged(size_in_bytes
@ -168,6 +169,7 @@ void *GC_malloc_weak_box(void *p, void **secondary, int soffset, int is_late)
GC_Weak_Box *w;
/* Allcation might trigger GC, so we use park: */
CHECK_PARK_UNUSED(gc);
gc->park[0] = p;
gc->park[1] = secondary;
@ -282,6 +284,7 @@ void *GC_malloc_ephemeron(void *k, void *v)
GC_Ephemeron *eph;
/* Allcation might trigger GC, so we use park: */
CHECK_PARK_UNUSED(gc);
gc->park[0] = k;
gc->park[1] = v;