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🐛 修复malloc扩容时int32溢出的bug，以及扩容堆内存后，由于未执行合并从而导致产生大量碎片的bug

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This commit is contained in:
fslongjin
2022-05-21 00:47:30 +08:00
parent 832c0c7e5c
commit 46ee327742
3 changed files with 25 additions and 16 deletions
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10
user/init.c
View File

@ -36,16 +36,16 @@ int main()
void *ptr[256] = {0};
for (int k = 0; k < 2; ++k)
{
printf("try to malloc 256*16K=4MB\n");
printf("try to malloc 256*1M=256MB\n");
uint64_t js = 0;
for (int i = 0; i < 256; ++i)
{
ptr[i] = malloc(4096 * 4);
ptr[i] = malloc(1024 * 1024);
js += *(uint64_t *)((uint64_t)(ptr[i]) - sizeof(uint64_t));
if (*(uint64_t *)((uint64_t)(ptr[i]) - sizeof(uint64_t)) > 0x4008)
printf("[%d] start_addr = %#018lx, len = %#010lx\n", (uint64_t)(ptr[i]) - 8, *(uint64_t *)((uint64_t)(ptr[i]) - sizeof(uint64_t)));
// if (*(uint64_t *)((uint64_t)(ptr[i]) - sizeof(uint64_t)) > 0x4008)
// printf("[%ld] start_addr = %#018lx, len = %#010lx\n", i, (uint64_t)(ptr[i]) - 8, *(uint64_t *)((uint64_t)(ptr[i]) - sizeof(uint64_t)));
}
// printf("ptr[0]->len=%lld\n", *(uint64_t *)((uint64_t)ptr[0] - sizeof(uint64_t)));
// printf("ptr[1]->len=%lld\n", *(uint64_t *)((uint64_t)ptr[1] - sizeof(uint64_t)));
// printf("ptr[24]->len=%lld\n", *(uint64_t*)((uint64_t)ptr[24] - sizeof(uint64_t)));

16
user/libs/libc/malloc.c
View File

@ -127,7 +127,7 @@ static malloc_mem_chunk_t *malloc_query_free_chunk_ff(uint64_t size)
*
* @param size 扩大的内存大小
*/
static int malloc_enlarge(int32_t size)
static int malloc_enlarge(int64_t size)
{
if (brk_base_addr == 0) // 第一次调用，需要初始化
{
@ -292,6 +292,9 @@ void *malloc(ssize_t size)
if (malloc_enlarge(size) == -ENOMEM)
return (void *)-ENOMEM; // 内存不足
malloc_merge_free_chunk(); // 扩容后运行合并，否则会导致碎片
// 扩容后再次尝试获取
ck = malloc_query_free_chunk_bf(size);
@ -326,7 +329,6 @@ found:;
malloc_insert_free_list(new_ck);
}
// 此时链表结点的指针的空间被分配出去
return (void *)((uint64_t)ck + sizeof(uint64_t));
}
@ -340,11 +342,17 @@ static void release_brk()
// 先检测最顶上的块
// 由于块按照开始地址排列，因此找最后一个块
if (malloc_free_list_end == NULL)
{
printf("release(): free list end is null. \n");
return;
}
if ((uint64_t)malloc_free_list_end + malloc_free_list_end->length == brk_max_addr && (uint64_t)malloc_free_list_end <= brk_max_addr - (PAGE_2M_SIZE << 1))
{
int64_t delta = (brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK - PAGE_2M_SIZE;
int64_t delta = ((brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK) - PAGE_2M_SIZE;
// printf("(brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK=%#018lx\n ", (brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK);
// printf("PAGE_2M_SIZE=%#018lx\n", PAGE_2M_SIZE);
// printf("tdfghgbdfggkmfn=%#018lx\n ", (brk_max_addr - (uint64_t)malloc_free_list_end) & PAGE_2M_MASK - PAGE_2M_SIZE);
// printf("delta=%#018lx\n ", delta);
if (delta <= 0) // 不用释放内存
return;
sbrk(-delta);