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authorPaolo Bonzini <pbonzini@redhat.com>2012-04-12 14:01:04 +0200
committerKevin Wolf <kwolf@redhat.com>2012-05-10 10:32:11 +0200
commit71df14fcbe5035d0728f30463414301eb62ad865 (patch)
tree173287c2a889188b8fb106e24212ea93c9e28b7b /block.c
parent63090dac3a7c5fe02b4285cf2e5fb7017d2c7b0e (diff)
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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>
Diffstat (limited to 'block.c')
-rw-r--r--block.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/block.c b/block.c
index 754a422..3db84cd 100644
--- a/block.c
+++ b/block.c
@@ -1584,6 +1584,8 @@ int bdrv_read(BlockDriverState *bs, int64_t sector_num,
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 @@ static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
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 @@ void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable)
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) {