kiper220/mimalloc
1
0
Fork 0
mirror of https://github.com/microsoft/mimalloc.git synced 2025-07-12 06:08:42 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions

merge from dev

Browse source
This commit is contained in:
daan 2020-01-13 18:01:34 -08:00
commit 4a27ea1643
24 changed files with 773 additions and 304 deletions
Download patch file Download diff file Expand all files Collapse all files

45
src/alloc.c
View file

@ -125,7 +125,7 @@ mi_decl_allocator void* mi_zalloc(size_t size) mi_attr_noexcept {
// ------------------------------------------------------
// Check for double free in secure and debug mode
// Check for double free in secure and debug mode
// This is somewhat expensive so only enabled for secure mode 4
// ------------------------------------------------------
@ -139,32 +139,29 @@ static bool mi_list_contains(const mi_page_t* page, const mi_block_t* list, cons
return false;
}
static mi_decl_noinline bool mi_check_is_double_freex(const mi_page_t* page, const mi_block_t* block, const mi_block_t* n) {
size_t psize;
uint8_t* pstart = _mi_page_start(_mi_page_segment(page), page, &psize);
if (n == NULL || ((uint8_t*)n >= pstart && (uint8_t*)n < (pstart + psize))) {
// Suspicious: the decoded value is in the same page (or NULL).
// Walk the free lists to verify positively if it is already freed
if (mi_list_contains(page, page->free, block) ||
mi_list_contains(page, page->local_free, block) ||
mi_list_contains(page, (const mi_block_t*)mi_atomic_read_ptr_relaxed(mi_atomic_cast(void*,&page->thread_free)), block))
{
_mi_fatal_error("double free detected of block %p with size %zu\n", block, page->block_size);
return true;
}
static mi_decl_noinline bool mi_check_is_double_freex(const mi_page_t* page, const mi_block_t* block) {
// The decoded value is in the same page (or NULL).
// Walk the free lists to verify positively if it is already freed
mi_thread_free_t tf = (mi_thread_free_t)mi_atomic_read_relaxed(mi_atomic_cast(uintptr_t, &page->thread_free));
if (mi_list_contains(page, page->free, block) ||
mi_list_contains(page, page->local_free, block) ||
mi_list_contains(page, mi_tf_block(tf), block))
{
_mi_fatal_error("double free detected of block %p with size %zu\n", block, page->block_size);
return true;
}
return false;
}
static inline bool mi_check_is_double_free(const mi_page_t* page, const mi_block_t* block) {
mi_block_t* n = mi_block_nextx(page, block, page->cookie); // pretend it is freed, and get the decoded first field
if (((uintptr_t)n & (MI_INTPTR_SIZE-1))==0 && // quick check: aligned pointer?
(n==NULL || mi_is_in_same_segment(block, n))) // quick check: in same segment or NULL?
{
// Suspicous: decoded value in block is in the same segment (or NULL) -- maybe a double free?
mi_block_t* n = mi_block_nextx(page, block, page->key[0], page->key[1]); // pretend it is freed, and get the decoded first field
if (((uintptr_t)n & (MI_INTPTR_SIZE-1))==0 && // quick check: aligned pointer?
(n==NULL || mi_is_in_same_page(block, n))) // quick check: in same page or NULL?
{
// Suspicous: decoded value a in block is in the same page (or NULL) -- maybe a double free?
// (continue in separate function to improve code generation)
return mi_check_is_double_freex(page, block, n);
}
return mi_check_is_double_freex(page, block);
}
return false;
}
#else
@ -237,7 +234,7 @@ static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* bloc
mi_block_t* dfree;
do {
dfree = (mi_block_t*)heap->thread_delayed_free;
mi_block_set_nextx(heap,block,dfree, heap->cookie);
mi_block_set_nextx(heap,block,dfree, heap->key[0], heap->key[1]);
} while (!mi_atomic_cas_ptr_weak(mi_atomic_cast(void*,&heap->thread_delayed_free), block, dfree));
}
@ -261,7 +258,7 @@ static inline void _mi_free_block(mi_page_t* page, bool local, mi_block_t* block
// and push it on the free list
if (mi_likely(local)) {
// owning thread can free a block directly
if (mi_check_is_double_free(page, block)) return;
if (mi_unlikely(mi_check_is_double_free(page, block))) return;
mi_block_set_next(page, block, page->local_free);
page->local_free = block;
page->used--;
@ -336,7 +333,7 @@ void mi_free(void* p) mi_attr_noexcept
if (mi_likely(tid == segment->thread_id && page->flags.full_aligned == 0)) { // the thread id matches and it is not a full page, nor has aligned blocks
// local, and not full or aligned
mi_block_t* block = (mi_block_t*)p;
if (mi_check_is_double_free(page,block)) return;
if (mi_unlikely(mi_check_is_double_free(page,block))) return;
mi_block_set_next(page, block, page->local_free);
page->local_free = block;
page->used--;