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Use checked addition for allocator implementations (#726)

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This commit is contained in:
Philipp Oppermann
2020-01-27 13:25:08 +01:00
committed by GitHub
parent 002d6f255f
commit 3ad5f117c2
2 changed files with 4 additions and 4 deletions
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4
src/allocator/bump.rs
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@@ -26,7 +26,7 @@ impl BumpAllocator {
/// memory range is unused. Also, this method must be called only once.
pub unsafe fn init(&mut self, heap_start: usize, heap_size: usize) {
self.heap_start = heap_start;
self.heap_end = heap_start + heap_size;
self.heap_end = heap_start.saturating_add(heap_size);
self.next = heap_start;
}
}
@@ -36,7 +36,7 @@ unsafe impl GlobalAlloc for Locked<BumpAllocator> {
let mut bump = self.lock(); // get a mutable reference
let alloc_start = align_up(bump.next, layout.align());
let alloc_end = alloc_start + layout.size();
let alloc_end = alloc_start.checked_add(layout.size()).expect("overflow");
if alloc_end > bump.heap_end {
ptr::null_mut() // out of memory

4
src/allocator/linked_list.rs
View File

@@ -86,7 +86,7 @@ impl LinkedListAllocator {
/// Returns the allocation start address on success.
fn alloc_from_region(region: &ListNode, size: usize, align: usize) -> Result<usize, ()> {
let alloc_start = align_up(region.start_addr(), align);
let alloc_end = alloc_start + size;
let alloc_end = alloc_start.checked_add(size).expect("overflow");
if alloc_end > region.end_addr() {
// region too small
@@ -125,7 +125,7 @@ unsafe impl GlobalAlloc for Locked<LinkedListAllocator> {
let mut allocator = self.inner.lock();
if let Some((region, alloc_start)) = allocator.find_region(size, align) {
let alloc_end = alloc_start + size;
let alloc_end = alloc_start.checked_add(size).expect("overflow");
let excess_size = region.end_addr() - alloc_end;
if excess_size > 0 {
allocator.add_free_region(alloc_end, excess_size);