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fix various false positives in test-stress from valgrind

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This commit is contained in:
daan 2022-10-29 14:37:55 -07:00
parent c61b365e76
commit a1f5a5d962
6 changed files with 50 additions and 36 deletions
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9
include/mimalloc-track.h
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@ -13,9 +13,6 @@ terms of the MIT license. A copy of the license can be found in the file
// or other memory checkers.
// ------------------------------------------------------
#define MI_VALGRIND 1
#if MI_VALGRIND
#define MI_TRACK_ENABLED 1
@ -23,9 +20,9 @@ terms of the MIT license. A copy of the license can be found in the file
#include <valgrind/valgrind.h>
#include <valgrind/memcheck.h>
#define mi_track_malloc(p,size,zero) VALGRIND_MALLOCLIKE_BLOCK(p,size,0 /*red zone*/,zero)
#define mi_track_resize(p,oldsize,newsize) VALGRIND_RESIZEINPLACE_BLOCK(p,oldsize,newsize,0 /*red zone*/)
#define mi_track_free(p) VALGRIND_FREELIKE_BLOCK(p,0 /*red zone*/)
#define mi_track_malloc(p,size,zero) VALGRIND_MALLOCLIKE_BLOCK(p,size,MI_PADDING_SIZE /*red zone*/,(zero?1:0))
#define mi_track_resize(p,oldsize,newsize) VALGRIND_RESIZEINPLACE_BLOCK(p,oldsize,newsize,MI_PADDING_SIZE /*red zone*/)
#define mi_track_free(p) VALGRIND_FREELIKE_BLOCK(p,MI_PADDING_SIZE /*red zone*/)
#define mi_track_mem_defined(p,size) VALGRIND_MAKE_MEM_DEFINED(p,size)
#define mi_track_mem_undefined(p,size) VALGRIND_MAKE_MEM_UNDEFINED(p,size)
#define mi_track_mem_noaccess(p,size) VALGRIND_MAKE_MEM_NOACCESS(p,size)

7
include/mimalloc-types.h
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@ -29,6 +29,9 @@ terms of the MIT license. A copy of the license can be found in the file
// Define NDEBUG in the release version to disable assertions.
// #define NDEBUG
// Define MI_VALGRIND to enable valgrind support
#define MI_VALGRIND 1
// Define MI_STAT as 1 to maintain statistics; set it to 2 to have detailed statistics (but costs some performance).
// #define MI_STAT 1
@ -56,7 +59,7 @@ terms of the MIT license. A copy of the license can be found in the file
// Reserve extra padding at the end of each block to be more resilient against heap block overflows.
// The padding can detect byte-precise buffer overflow on free.
#if !defined(MI_PADDING) && (MI_DEBUG>=1)
#if !defined(MI_PADDING) && (MI_DEBUG>=1 || MI_VALGRIND)
#define MI_PADDING 1
#endif
@ -64,7 +67,7 @@ terms of the MIT license. A copy of the license can be found in the file
// Encoded free lists allow detection of corrupted free lists
// and can detect buffer overflows, modify after free, and double `free`s.
#if (MI_SECURE>=3 || MI_DEBUG>=1 || MI_PADDING > 0)
#define MI_ENCODE_FREELIST 1
#define MI_ENCODE_FREELIST 1
#endif

48
src/alloc.c
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@ -40,7 +40,10 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
// allow use of the block internally
// todo: can we optimize this call away for non-zero'd release mode?
mi_track_mem_undefined(block,mi_page_block_size(page));
#if MI_TRACK_ENABLED
const size_t track_bsize = mi_page_block_size(page);
if (zero) mi_track_mem_defined(block,track_bsize); else mi_track_mem_undefined(block,track_bsize);
#endif
// zero the block? note: we need to zero the full block size (issue #63)
if mi_unlikely(zero) {
@ -70,7 +73,10 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
#if (MI_PADDING > 0) && defined(MI_ENCODE_FREELIST)
mi_padding_t* const padding = (mi_padding_t*)((uint8_t*)block + mi_page_usable_block_size(page));
ptrdiff_t delta = ((uint8_t*)padding - (uint8_t*)block - (size - MI_PADDING_SIZE));
#if (MI_DEBUG>1)
mi_assert_internal(delta >= 0 && mi_page_usable_block_size(page) >= (size - MI_PADDING_SIZE + delta));
mi_track_mem_defined(padding,sizeof(mi_padding_t)); // note: re-enable since mi_page_usable_block_size may set noaccess
#endif
padding->canary = (uint32_t)(mi_ptr_encode(page,block,page->keys));
padding->delta = (uint32_t)(delta);
uint8_t* fill = (uint8_t*)padding - delta;
@ -79,7 +85,7 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
#endif
// mark as no-access again
mi_track_mem_noaccess(block,mi_page_block_size(page));
mi_track_mem_noaccess(block,track_bsize);
return block;
}
@ -215,10 +221,14 @@ static inline bool mi_check_is_double_free(const mi_page_t* page, const mi_block
static bool mi_page_decode_padding(const mi_page_t* page, const mi_block_t* block, size_t* delta, size_t* bsize) {
*bsize = mi_page_usable_block_size(page);
const mi_padding_t* const padding = (mi_padding_t*)((uint8_t*)block + *bsize);
mi_track_mem_defined(padding,sizeof(*padding));
mi_track_mem_defined(padding,sizeof(mi_padding_t));
*delta = padding->delta;
bool ok = ((uint32_t)mi_ptr_encode(page,block,page->keys) == padding->canary && *delta <= *bsize);
mi_track_mem_noaccess(padding,sizeof(*padding));
uint32_t canary = padding->canary;
uintptr_t keys[2];
keys[0] = page->keys[0];
keys[1] = page->keys[1];
bool ok = ((uint32_t)mi_ptr_encode(page,block,keys) == canary && *delta <= *bsize);
mi_track_mem_noaccess(padding,sizeof(mi_padding_t));
return ok;
}
@ -349,9 +359,9 @@ static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* bloc
// The padding check may access the non-thread-owned page for the key values.
// that is safe as these are constant and the page won't be freed (as the block is not freed yet).
mi_check_padding(page, block);
mi_padding_shrink(page, block, sizeof(mi_block_t)); // for small size, ensure we can fit the delayed thread pointers without triggering overflow detection
#if (MI_DEBUG!=0)
mi_track_mem_undefined(block, mi_page_block_size(page)); // note: check padding may set parts to noaccess
mi_track_mem_defined(block, mi_page_block_size(page)); // ensure the padding can be accessed
mi_padding_shrink(page, block, sizeof(mi_block_t)); // for small size, ensure we can fit the delayed thread pointers without triggering overflow detection
#if (MI_DEBUG!=0) && !MI_TRACK_ENABLED // note: when tracking, cannot use mi_usable_size with multi-threading
memset(block, MI_DEBUG_FREED, mi_usable_size(block));
#endif
@ -406,6 +416,7 @@ static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* bloc
static inline void _mi_free_block(mi_page_t* page, bool local, mi_block_t* block)
{
// and push it on the free list
//const size_t bsize = mi_page_block_size(page);
if mi_likely(local) {
// owning thread can free a block directly
if mi_unlikely(mi_check_is_double_free(page, block)) return;
@ -442,8 +453,13 @@ mi_block_t* _mi_page_ptr_unalign(const mi_segment_t* segment, const mi_page_t* p
static void mi_decl_noinline mi_free_generic(const mi_segment_t* segment, bool local, void* p) mi_attr_noexcept {
mi_page_t* const page = _mi_segment_page_of(segment, p);
mi_block_t* const block = (mi_page_has_aligned(page) ? _mi_page_ptr_unalign(segment, page, p) : (mi_block_t*)p);
mi_stat_free(page, block);
//#if MI_TRACK_ENABLED
//const size_t track_bsize = mi_page_block_size(page);
//#endif
//mi_track_mem_defined(block,track_bsize);
mi_stat_free(page, block); // stat_free may access the padding
_mi_free_block(page, local, block);
//mi_track_mem_noaccess(block,track_bsize); // use track_bsize as the page may have been deallocated by now
}
// Get the segment data belonging to a pointer
@ -485,27 +501,22 @@ void mi_free(void* p) mi_attr_noexcept
{
mi_segment_t* const segment = mi_checked_ptr_segment(p,"mi_free");
if mi_unlikely(segment == NULL) return;
mi_track_free(p);
mi_threadid_t tid = _mi_thread_id();
mi_page_t* const page = _mi_segment_page_of(segment, p);
mi_block_t* const block = (mi_block_t*)p;
#if MI_TRACK_ENABLED
const size_t track_bsize = mi_page_block_size(page);
#endif
if mi_likely(tid == mi_atomic_load_relaxed(&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
if mi_unlikely(mi_check_is_double_free(page,block)) return;
mi_check_padding(page, block);
mi_stat_free(page, block);
#if (MI_DEBUG!=0)
mi_track_mem_undefined(block,track_bsize); // note: check padding may set parts to noaccess
#if (MI_DEBUG!=0) && !MI_TRACK_ENABLED
memset(block, MI_DEBUG_FREED, mi_page_block_size(page));
#endif
mi_block_set_next(page, block, page->local_free);
page->local_free = block;
// mi_track_mem_noaccess(block,mi_page_block_size(page));
if mi_unlikely(--page->used == 0) { // using this expression generates better code than: page->used--; if (mi_page_all_free(page))
_mi_page_retire(page);
}
@ -513,10 +524,9 @@ void mi_free(void* p) mi_attr_noexcept
else {
// non-local, aligned blocks, or a full page; use the more generic path
// note: recalc page in generic to improve code generation
mi_track_mem_undefined(block,track_bsize);
mi_free_generic(segment, tid == segment->thread_id, p);
}
mi_track_mem_noaccess(block,track_bsize); // cannot use mi_page_block_size as the segment might be deallocated by now
}
mi_track_free(p);
}
bool _mi_free_delayed_block(mi_block_t* block) {

6
src/region.c
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@ -330,7 +330,7 @@ static void* mi_region_try_alloc(size_t blocks, bool* commit, bool* large, bool*
}
mi_assert_internal(!_mi_bitmap_is_any_claimed(&region->reset, 1, blocks, bit_idx));
#if (MI_DEBUG>=2)
#if (MI_DEBUG>=2) && !MI_TRACK_ENABLED
if (*commit) { ((uint8_t*)p)[0] = 0; }
#endif
@ -376,9 +376,9 @@ void* _mi_mem_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* l
if (p != NULL) {
mi_assert_internal((uintptr_t)p % alignment == 0);
#if (MI_DEBUG>=2)
#if (MI_DEBUG>=2) && !MI_TRACK_ENABLED
if (*commit) { ((uint8_t*)p)[0] = 0; } // ensure the memory is committed
#endif
#endif
}
return p;
}

7
src/segment.c
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@ -531,6 +531,7 @@ static mi_segment_t* mi_segment_init(mi_segment_t* segment, size_t required, mi_
// Try to get it from our thread local cache first
if (segment != NULL) {
// came from cache
mi_track_mem_defined(segment,info_size);
mi_assert_internal(segment->segment_size == segment_size);
if (page_kind <= MI_PAGE_MEDIUM && segment->page_kind == page_kind && segment->segment_size == segment_size) {
pages_still_good = true;
@ -584,15 +585,15 @@ static mi_segment_t* mi_segment_init(mi_segment_t* segment, size_t required, mi_
return NULL;
}
}
mi_track_mem_undefined(segment,info_size);
segment->memid = memid;
segment->mem_is_pinned = (mem_large || is_pinned);
segment->mem_is_committed = commit;
mi_segments_track_size((long)segment_size, tld);
}
mi_assert_internal(segment != NULL && (uintptr_t)segment % MI_SEGMENT_SIZE == 0);
mi_assert_internal(segment->mem_is_pinned ? segment->mem_is_committed : true);
mi_track_mem_defined(segment,info_size);
mi_assert_internal(segment->mem_is_pinned ? segment->mem_is_committed : true);
mi_atomic_store_ptr_release(mi_segment_t, &segment->abandoned_next, NULL); // tsan
if (!pages_still_good) {
// zero the segment info (but not the `mem` fields)

9
test/test-wrong.c
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@ -16,17 +16,20 @@ int main(int argc, char** argv) {
mi_free(r);
// undefined access
// printf("undefined: %d\n", *q);
printf("undefined: %d\n", *q);
*q = 42;
// buffer overflow
// q[1] = 43;
q[1] = 43;
// buffer underflow
q[-1] = 44;
mi(free)(q);
// double free
// mi(free)(q);
mi(free)(q);
// use after free
printf("use-after-free: %d\n", *q);