Poison / verify the freelist

This commit just adds poisoning around the freelist to help debugging.
Also verify that the freelist only contains T_NONE objects when checking
the heap integrity

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67416 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
tenderlove 2019-04-02 19:13:07 +00:00
parent f28be7e02d
commit 4283fb42bc

34
gc.c
View File

@ -1425,9 +1425,12 @@ static inline void
heap_page_add_freeobj(rb_objspace_t *objspace, struct heap_page *page, VALUE obj)
{
RVALUE *p = (RVALUE *)obj;
unpoison_memory_region(&page->freelist, sizeof(RVALUE*), false);
p->as.free.flags = 0;
p->as.free.next = page->freelist;
page->freelist = p;
__asan_poison_memory_region(&page->freelist, sizeof(RVALUE*));
if (RGENGC_CHECK_MODE && !is_pointer_to_heap(objspace, p)) {
rb_bug("heap_page_add_freeobj: %p is not rvalue.", (void *)p);
@ -1440,23 +1443,30 @@ heap_page_add_freeobj(rb_objspace_t *objspace, struct heap_page *page, VALUE obj
static inline void
heap_add_freepage(rb_objspace_t *objspace, rb_heap_t *heap, struct heap_page *page)
{
unpoison_memory_region(&page->freelist, sizeof(RVALUE*), false);
if (page->freelist) {
page->free_next = heap->free_pages;
heap->free_pages = page;
}
poison_memory_region(&page->freelist, sizeof(RVALUE*));
}
#if GC_ENABLE_INCREMENTAL_MARK
static inline int
heap_add_poolpage(rb_objspace_t *objspace, rb_heap_t *heap, struct heap_page *page)
{
unpoison_memory_region(&page->freelist, sizeof(RVALUE*), false);
if (page->freelist) {
page->free_next = heap->pooled_pages;
heap->pooled_pages = page;
objspace->rincgc.pooled_slots += page->free_slots;
poison_memory_region(&page->freelist, sizeof(RVALUE*));
return TRUE;
}
else {
poison_memory_region(&page->freelist, sizeof(RVALUE*));
return FALSE;
}
}
@ -1585,6 +1595,7 @@ heap_page_allocate(rb_objspace_t *objspace)
}
page->free_slots = limit;
poison_memory_region(&page->freelist, sizeof(RVALUE*));
return page;
}
@ -1594,8 +1605,10 @@ heap_page_resurrect(rb_objspace_t *objspace)
struct heap_page *page = 0, *next;
list_for_each_safe(&heap_tomb->pages, page, next, page_node) {
unpoison_memory_region(&page->freelist, sizeof(RVALUE*), false);
if (page->freelist != NULL) {
heap_unlink_page(objspace, heap_tomb, page);
poison_memory_region(&page->freelist, sizeof(RVALUE*));
return page;
}
}
@ -1754,8 +1767,10 @@ heap_get_freeobj_from_next_freepage(rb_objspace_t *objspace, rb_heap_t *heap)
heap->using_page = page;
GC_ASSERT(page->free_slots != 0);
unpoison_memory_region(&page->freelist, sizeof(RVALUE*), false);
p = page->freelist;
page->freelist = NULL;
poison_memory_region(&page->freelist, sizeof(RVALUE*));
page->free_slots = 0;
unpoison_object((VALUE)p, true);
return p;
@ -3745,11 +3760,15 @@ gc_sweep_start_heap(rb_objspace_t *objspace, rb_heap_t *heap)
objspace->rincgc.pooled_slots = 0;
#endif
if (heap->using_page) {
RVALUE **p = &heap->using_page->freelist;
struct heap_page *page = heap->using_page;
unpoison_memory_region(&page->freelist, sizeof(RVALUE*), false);
RVALUE **p = &page->freelist;
while (*p) {
p = &(*p)->as.free.next;
}
*p = heap->freelist;
poison_memory_region(&page->freelist, sizeof(RVALUE*));
heap->using_page = NULL;
}
heap->freelist = NULL;
@ -5445,6 +5464,19 @@ gc_verify_heap_pages_(rb_objspace_t *objspace, struct list_head *head)
struct heap_page *page = 0;
list_for_each(head, page, page_node) {
unpoison_memory_region(&page->freelist, sizeof(RVALUE*), false);
RVALUE *p = page->freelist;
while(p) {
RVALUE *prev = p;
unpoison_object(p, false);
if (BUILTIN_TYPE(p) != T_NONE) {
fprintf(stderr, "freelist slot expected to be T_NONE but was: %s\n", obj_info((VALUE)p));
}
p = p->as.free.next;
poison_object(prev);
}
poison_memory_region(&page->freelist, sizeof(RVALUE*));
if (page->flags.has_remembered_objects == FALSE) {
remembered_old_objects += gc_verify_heap_page(objspace, page, Qfalse);
}