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--- libmalloc/libmalloc-283.60.1/src/nanov2_malloc.c
+++ libmalloc/libmalloc-317.100.9/src/nanov2_malloc.c
@@ -239,13 +239,14 @@
// Given a block metadata pointer, returns whether the block is active (that is,
// it is being used for allocations, it has allocations that have not been freed,
-// or is waiting to be madvised).
+// or is waiting to be madvised and is not a guard block).
static MALLOC_ALWAYS_INLINE MALLOC_INLINE boolean_t
nanov2_is_block_active(nanov2_block_meta_t block_meta)
{
return block_meta.next_slot != SLOT_NULL
&& block_meta.next_slot != SLOT_MADVISING
- && block_meta.next_slot != SLOT_MADVISED;
+ && block_meta.next_slot != SLOT_MADVISED
+ && block_meta.next_slot != SLOT_GUARD;
}
#if OS_VARIANT_RESOLVED
@@ -595,15 +596,15 @@
#if CONFIG_NANO_USES_HYPER_SHIFT
if (os_likely(nano_common_max_magazines_is_ncpu)) {
// Default case is max magazines == physical number of CPUs, which
- // must be > _os_cpu_number() >> hyper_shift, so the modulo
+ // must be > _malloc_cpu_number() >> hyper_shift, so the modulo
// operation is not required.
- return _os_cpu_number() >> hyper_shift;
+ return _malloc_cpu_number() >> hyper_shift;
}
#else // CONFIG_NANO_USES_HYPER_SHIFT
if (os_likely(nano_common_max_magazines_is_ncpu)) {
// Default case is max magazines == logical number of CPUs, which
- // must be > _os_cpu_number() so the modulo operation is not required.
- return _os_cpu_number();
+ // must be > _malloc_cpu_number() so the modulo operation is not required.
+ return _malloc_cpu_number();
}
#endif // CONFIG_NANO_USES_HYPER_SHIFT
@@ -613,11 +614,62 @@
#endif // CONFIG_NANO_USES_HYPER_SHIFT
if (os_likely(_os_cpu_number_override == -1)) {
- return (_os_cpu_number() >> shift) % nano_common_max_magazines;
+ return (_malloc_cpu_number() >> shift) % nano_common_max_magazines;
}
return (_os_cpu_number_override >> shift) % nano_common_max_magazines;
}
#endif // OS_VARIANT_RESOLVED
+
+#pragma mark -
+#pragma mark Guard Blocks
+
+// Converts a given block (specified by absolute block number) in an arena into
+// a guard block. The block will be marked as in-use so that it is not available
+// for allocations and its permissions are set to PROT_READ. Note that
+// PROT_READ is used instead of PROT_NONE because the latter breaks the
+// enumerator, which tries to map the whole region and fails if there are
+// PROT_NONE pages in the range. We can't fix that in the allocator because the
+// code that does the mapping is part of the sampling tools and is simply
+// invoked as a callback from the enumerator.
+static MALLOC_ALWAYS_INLINE MALLOC_INLINE void
+nanov2_create_guard_block(nanozonev2_t *nanozone, nanov2_arena_t *arena,
+ nanov2_block_index_t block_index) {
+ // Mark the block as in-use in the meta data
+ static nanov2_block_meta_t in_use_block = {
+ .in_use = 1,
+ .next_slot = SLOT_GUARD
+ };
+ nanov2_meta_index_t block_meta_index =
+ nanov2_block_index_to_meta_index(block_index);
+ nanov2_arena_metablock_t *block_metap = nanov2_metablock_address_for_ptr(
+ nanozone, arena);
+ block_metap->arena_block_meta[block_meta_index] = in_use_block;
+ void *block_ptr = &arena->blocks[block_index];
+
+ // Apply PROT_NONE to the block itself.
+ kern_return_t err = mprotect(block_ptr, NANOV2_BLOCK_SIZE, PROT_READ);
+ if (err != KERN_SUCCESS) {
+ malloc_report(ASL_LEVEL_ERR, "Failed to create guard block at %p (%d)\n",
+ block_ptr, err);
+ }
+}
+
+// Creates the guard blocks for an arena, if required. The guard blocks are
+// the first and last physical blocks in the arena that are not the metadata
+// block.
+static MALLOC_ALWAYS_INLINE MALLOC_INLINE void
+nanov2_init_guard_blocks(nanozonev2_t *nanozone, nanov2_arena_t *arena)
+{
+ if (nanozone->debug_flags & MALLOC_ALL_GUARD_PAGE_FLAGS) {
+ // Use the first and last blocks in the arena as guard regions,
+ // avoiding the metadata block.
+ nanov2_meta_index_t meta_index = nanov2_metablock_meta_index(nanozone);
+ nanov2_create_guard_block(nanozone, arena, meta_index == 0 ? 1 : 0);
+ nanov2_create_guard_block(nanozone, arena,
+ meta_index == NANOV2_BLOCKS_PER_ARENA - 1 ?
+ NANOV2_BLOCKS_PER_ARENA - 2 : NANOV2_BLOCKS_PER_ARENA - 1);
+ }
+}
#pragma mark -
#pragma mark Allocator Initialization
@@ -1699,7 +1751,7 @@
}
static void
-null_printer(const char __unused *fmt, ...)
+nanov2_null_printer(const char __unused *fmt, ...)
{
}
@@ -1708,7 +1760,7 @@
memory_reader_t reader, print_task_printer_t printer,
malloc_statistics_t *stats)
{
- printer = printer ? printer : null_printer;
+ printer = printer ? printer : nanov2_null_printer;
reader = !reader && task == mach_task_self() ? _malloc_default_reader : reader;
kern_return_t err;
@@ -1773,6 +1825,8 @@
case SLOT_MADVISING:
// FALLTHRU
case SLOT_MADVISED:
+ // FALLTHRU
+ case SLOT_GUARD:
// These blocks have no active content.
break;
case SLOT_FULL:
@@ -2150,8 +2204,7 @@
ptr = nanov2_slot_in_block_ptr(blockp, size_class, slot);
}
- nanov2_free_slot_t *slotp =
- (nanov2_free_slot_t *)os_atomic_force_dependency_on(ptr,
+ nanov2_free_slot_t *slotp = os_atomic_inject_dependency(ptr,
(unsigned long)old_meta_view.bits);
if (from_free_list) {
// We grabbed the item from the free list. Check the free list canary
@@ -2160,7 +2213,7 @@
// write to it.
uintptr_t guard = os_atomic_load(&slotp->double_free_guard, relaxed);
if ((guard ^ nanozone->slot_freelist_cookie) != (uintptr_t)ptr) {
- malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, false,
+ malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, true,
"Heap corruption detected, free list is damaged at %p\n"
"*** Incorrect guard value: %lu\n", ptr, guard);
__builtin_unreachable();
@@ -2477,6 +2530,11 @@
// Assign the new arena, in the same region.
nanozone->current_region_next_arena = arena + 1;
}
+
+ // Set up the guard blocks for the new arena, if requested
+ if (!failed) {
+ nanov2_init_guard_blocks(nanozone, arena);
+ }
}
_malloc_lock_unlock(&nanozone->regions_lock);
@@ -2710,12 +2768,6 @@
// Prevent overwriting the function pointers in basic_zone.
mprotect(nanozone, sizeof(nanozone->basic_zone), PROT_READ);
- // Nano V2 zone does not support MALLOC_ADD_GUARD_PAGES
- if (debug_flags & MALLOC_ADD_GUARD_PAGES) {
- malloc_report(ASL_LEVEL_INFO, "nano does not support guard pages\n");
- debug_flags &= ~MALLOC_ADD_GUARD_PAGES;
- }
-
// Set up the remainder of the nanozonev2 structure
nanozone->debug_flags = debug_flags;
nanozone->helper_zone = helper_zone;
@@ -2766,6 +2818,9 @@
nanozone->current_region_next_arena = ((nanov2_arena_t *)region) + 1;
nanozone->current_region_limit = region + 1;
nanozone->statistics.allocated_regions = 1;
+
+ // Set up the guard blocks for the initial arena, if requested
+ nanov2_init_guard_blocks(nanozone, (nanov2_arena_t *)region);
return (malloc_zone_t *)nanozone;
}