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free() now fills the freed memory with 0xdeadbeef if PARANOID_KFREE is defined

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(except for the first 4 bytes, because that's the pointer to the next buffer
in the free list).


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4299 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2003-08-18 03:35:57 +00:00
parent 782a460588
commit 54711c1b89
1 changed files with 14 additions and 1 deletions
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15
src/kernel/core/heap.c
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@ -27,7 +27,7 @@
#define PARANOID_POINTER_CHECK 1
/* initialize newly allocated memory with something non zero */
#define PARANOID_KMALLOC 1
/* check if freed pointers are already freed */
/* check if freed pointers are already freed, and fill freed memory with 0xdeadbeef */
#define PARANOID_KFREE 1
/* use a back and front wall around each allocation */
/* does currently not work correctly, because the VM malloc()s a PAGE_SIZE and
@ -375,6 +375,19 @@ free(void *address)
if (bin->element_size <= PAGE_SIZE && (addr)address % bin->element_size != 0)
panic("kfree: passed invalid pointer %p! Supposed to be in bin for esize 0x%x\n", address, bin->element_size);
#if PARANOID_KFREE
// mark the free space as freed
{
uint32 deadbeef = 0xdeadbeef;
uint8 *dead = (uint8 *)address;
int32 i;
// the first 4 bytes are overwritten with the next free list pointer later
for (i = 4; i < bin->element_size; i++)
dead[i] = ((uint8 *)&deadbeef)[i % 4];
}
#endif
for (i = 0; i < bin->element_size / PAGE_SIZE; i++) {
if (page[i].bin_index != page[0].bin_index)
panic("free(): not all pages in allocation match bin_index\n");