block: fix allocation size for dirty bitmap
Also reuse elsewhere the new constant for sizeof(unsigned long) * 8.
The dirty bitmap is allocated in bits but declared as unsigned long.
Thus, its memory block is accessed beyond its end unless the image
is a multiple of 64 chunks (i.e. a multiple of 64 MB).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 754a422..3db84cd 100644
--- a/block.c
+++ b/block.c
@@ -1584,6 +1584,8 @@
return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
}
+#define BITS_PER_LONG (sizeof(unsigned long) * 8)
+
static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int dirty)
{
@@ -1594,8 +1596,8 @@
end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
for (; start <= end; start++) {
- idx = start / (sizeof(unsigned long) * 8);
- bit = start % (sizeof(unsigned long) * 8);
+ idx = start / BITS_PER_LONG;
+ bit = start % BITS_PER_LONG;
val = bs->dirty_bitmap[idx];
if (dirty) {
if (!(val & (1UL << bit))) {
@@ -3900,10 +3902,10 @@
if (enable) {
if (!bs->dirty_bitmap) {
bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +
- BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
- bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
+ BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG - 1;
+ bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG;
- bs->dirty_bitmap = g_malloc0(bitmap_size);
+ bs->dirty_bitmap = g_new0(unsigned long, bitmap_size);
}
} else {
if (bs->dirty_bitmap) {
