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fix potential race on subproc field in the segment

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daanx 2024-06-03 20:57:00 -07:00
parent 76b0873ce2
commit b1188ea336
5 changed files with 19 additions and 21 deletions
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4
include/mimalloc/types.h
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@ -397,9 +397,10 @@ typedef struct mi_segment_s {
bool allow_decommit;
bool allow_purge;
size_t segment_size; // for huge pages this may be different from `MI_SEGMENT_SIZE`
mi_subproc_t* subproc; // segment belongs to sub process
// segment fields
struct mi_segment_s* next; // must be the first segment field after abandoned_next -- see `segment.c:segment_init`
struct mi_segment_s* next; // must be the first (non-constant) segment field -- see `segment.c:segment_init`
struct mi_segment_s* prev;
bool was_reclaimed; // true if it was reclaimed (used to limit on-free reclamation)
@ -410,7 +411,6 @@ typedef struct mi_segment_s {
size_t capacity; // count of available pages (`#free + used`)
size_t segment_info_size;// space we are using from the first page for segment meta-data and possible guard pages.
uintptr_t cookie; // verify addresses in secure mode: `_mi_ptr_cookie(segment) == segment->cookie`
mi_subproc_t* subproc; // segment belongs to sub process
struct mi_segment_s* abandoned_os_next; // only used for abandoned segments outside arena's, and only if `mi_option_visit_abandoned` is enabled
struct mi_segment_s* abandoned_os_prev;

3
src/arena-abandoned.c
View file

@ -162,8 +162,9 @@ void _mi_arena_segment_mark_abandoned(mi_segment_t* segment)
mi_arena_t* arena = mi_arena_from_index(arena_idx);
mi_assert_internal(arena != NULL);
// set abandonment atomically
mi_subproc_t* const subproc = segment->subproc; // don't access the segment after setting it abandoned
const bool was_unmarked = _mi_bitmap_claim(arena->blocks_abandoned, arena->field_count, 1, bitmap_idx, NULL);
if (was_unmarked) { mi_atomic_increment_relaxed(&segment->subproc->abandoned_count); }
if (was_unmarked) { mi_atomic_increment_relaxed(&subproc->abandoned_count); }
mi_assert_internal(was_unmarked);
mi_assert_internal(_mi_bitmap_is_claimed(arena->blocks_inuse, arena->field_count, 1, bitmap_idx));
}

2
src/segment.c
View file

@ -563,6 +563,7 @@ static mi_segment_t* mi_segment_os_alloc(bool eager_delayed, size_t page_alignme
segment->allow_decommit = !memid.is_pinned;
segment->allow_purge = segment->allow_decommit && (mi_option_get(mi_option_purge_delay) >= 0);
segment->segment_size = segment_size;
segment->subproc = tld->subproc;
mi_segments_track_size((long)(segment_size), tld);
_mi_segment_map_allocated_at(segment);
return segment;
@ -628,7 +629,6 @@ static mi_segment_t* mi_segment_alloc(size_t required, mi_page_kind_t page_kind,
segment->segment_info_size = pre_size;
segment->thread_id = _mi_thread_id();
segment->cookie = _mi_ptr_cookie(segment);
segment->subproc = tld->subproc;
// set protection
mi_segment_protect(segment, true, tld->os);

13
test/test-stress.c
View file

@ -25,17 +25,14 @@ terms of the MIT license.
// > mimalloc-test-stress [THREADS] [SCALE] [ITER]
//
// argument defaults
#if !defined(MI_TSAN)
static int THREADS = 32; // more repeatable if THREADS <= #processors
static int SCALE = 25; // scaling factor
#if defined(MI_TSAN)
static int ITER = 10; // N full iterations destructing and re-creating all threads (on tsan reduce for azure pipeline limits)
#else
static int ITER = 50; // N full iterations destructing and re-creating all threads
#else // with thread-sanitizer reduce the defaults for azure pipeline limits
static int THREADS = 8;
#endif
// static int THREADS = 8; // more repeatable if THREADS <= #processors
// static int SCALE = 100; // scaling factor
static int SCALE = 25; // scaling factor
static int ITER = 50; // N full iterations destructing and re-creating all threads
#define STRESS // undefine for leak test