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libc/minimal: restore proper locking for malloc() and friends

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Commit 40016a6a92 ("libc/minimal: Use a sys_heap for the malloc
implementation") replaced sys_mem_pool_alloc() with sys_heap_alloc().
The problem is that those aren't equivalent. While the former did
guard against concurrent usage, the later doesn't.

Add the same locking around sys_heap_alloc() that used to be implicit
with sys_mem_pool_alloc().

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2021-02-02 22:34:21 -05:00 • committed by Anas Nashif
commit e539bb1979
1 changed files with 21 additions and 0 deletions
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21
lib/libc/minimal/source/stdlib/malloc.c
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@ -11,6 +11,8 @@
#include <sys/math_extras.h>
#include <string.h>
#include <app_memory/app_memdomain.h>
#include <sys/check.h>
#include <sys/mutex.h>
#include <sys/sys_heap.h>
#include <zephyr/types.h>
@ -31,10 +33,17 @@ K_APPMEM_PARTITION_DEFINE(z_malloc_partition);
#define HEAP_BYTES CONFIG_MINIMAL_LIBC_MALLOC_ARENA_SIZE
Z_GENERIC_SECTION(POOL_SECTION) static struct sys_heap z_malloc_heap;
Z_GENERIC_SECTION(POOL_SECTION) struct sys_mutex z_malloc_heap_mutex;
Z_GENERIC_SECTION(POOL_SECTION) static char z_malloc_heap_mem[HEAP_BYTES];
void *malloc(size_t size)
{
int lock_ret = sys_mutex_lock(&z_malloc_heap_mutex, K_FOREVER);
CHECKIF(lock_ret != 0) {
return NULL;
}
void *ret = sys_heap_aligned_alloc(&z_malloc_heap,
__alignof__(z_max_align_t),
size);
@ -42,6 +51,7 @@ void *malloc(size_t size)
errno = ENOMEM;
}
sys_mutex_unlock(&z_malloc_heap_mutex);
return ret;
}
@ -50,12 +60,19 @@ static int malloc_prepare(const struct device *unused)
ARG_UNUSED(unused);
sys_heap_init(&z_malloc_heap, z_malloc_heap_mem, HEAP_BYTES);
sys_mutex_init(&z_malloc_heap_mutex);
return 0;
}
void *realloc(void *ptr, size_t requested_size)
{
int lock_ret = sys_mutex_lock(&z_malloc_heap_mutex, K_FOREVER);
CHECKIF(lock_ret != 0) {
return NULL;
}
void *ret = sys_heap_aligned_realloc(&z_malloc_heap, ptr,
__alignof__(z_max_align_t),
requested_size);
@ -63,12 +80,16 @@ void *realloc(void *ptr, size_t requested_size)
if (ret == NULL && requested_size != 0) {
errno = ENOMEM;
}
sys_mutex_unlock(&z_malloc_heap_mutex);
return ret;
}
void free(void *ptr)
{
sys_mutex_lock(&z_malloc_heap_mutex, K_FOREVER);
sys_heap_free(&z_malloc_heap, ptr);
sys_mutex_unlock(&z_malloc_heap_mutex);
}
SYS_INIT(malloc_prepare, APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);