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| author | Stefan Reiter | 2020-10-21 16:44:56 +0200 |
|---|---|---|
| committer | Eric Blake | 2020-10-26 12:55:37 +0100 |
| commit | ed7b70c27b5c11ff4800e608d301cd7a36b81c5e (patch) | |
| tree | 4785a7ba48aefa565a9a2585fe96c2457db1b517 /migration/block-dirty-bitmap.c | |
| parent | Merge remote-tracking branch 'remotes/kraxel/tags/modules-20201022-pull-reque... (diff) | |
| download | qemu-ed7b70c27b5c11ff4800e608d301cd7a36b81c5e.tar.gz qemu-ed7b70c27b5c11ff4800e608d301cd7a36b81c5e.tar.xz qemu-ed7b70c27b5c11ff4800e608d301cd7a36b81c5e.zip | |
migration/block-dirty-bitmap: fix larger granularity bitmaps
sectors_per_chunk is a 64 bit integer, but the calculation is done in 32
bits, leading to an overflow for coarse bitmap granularities.
If that results in the value 0, it leads to a hang where no progress is
made but send_bitmap_bits is constantly called with nr_sectors being 0.
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
Message-Id: <20201021144456.1072-1-s.reiter@proxmox.com>
Fixes: b35ebdf07 migration: add postcopy migration of dirty bitmaps
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: Use correct type for 8ULL, use () to avoid overflow]
Signed-off-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'migration/block-dirty-bitmap.c')
| -rw-r--r-- | migration/block-dirty-bitmap.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c index 5bef793ac0..98921db772 100644 --- a/migration/block-dirty-bitmap.c +++ b/migration/block-dirty-bitmap.c @@ -562,8 +562,9 @@ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs, dbms->bitmap_alias = g_strdup(bitmap_alias); dbms->bitmap = bitmap; dbms->total_sectors = bdrv_nb_sectors(bs); - dbms->sectors_per_chunk = CHUNK_SIZE * 8 * - bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS; + dbms->sectors_per_chunk = CHUNK_SIZE * 8LLU * + (bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS); + assert(dbms->sectors_per_chunk != 0); if (bdrv_dirty_bitmap_enabled(bitmap)) { dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_ENABLED; } |