From ed7b70c27b5c11ff4800e608d301cd7a36b81c5e Mon Sep 17 00:00:00 2001 From: Stefan Reiter Date: Wed, 21 Oct 2020 16:44:56 +0200 Subject: [PATCH 1/2] 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 Message-Id: <20201021144456.1072-1-s.reiter@proxmox.com> Fixes: b35ebdf07 migration: add postcopy migration of dirty bitmaps Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake [eblake: Use correct type for 8ULL, use () to avoid overflow] Signed-off-by: Eric Blake --- migration/block-dirty-bitmap.c | 5 +++-- 1 file 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; } From a024890a64085d3d37ad7eda164775251285c14c Mon Sep 17 00:00:00 2001 From: Chen Qun Date: Wed, 14 Oct 2020 19:44:30 +0800 Subject: [PATCH 2/2] migration/block-dirty-bitmap: fix uninitialized variable warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A default value is provided for the variable 'bitmap_name' to avoid a compiler warning. The compiler showed the warning: migration/block-dirty-bitmap.c:1090:13: warning: ‘bitmap_name’ may be used uninitialized in this function [-Wmaybe-uninitialized] g_strlcpy(s->bitmap_name, bitmap_name, sizeof(s->bitmap_name)); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Reported-by: Euler Robot Signed-off-by: Chen Qun Message-Id: <20201014114430.1898684-1-kuhn.chenqun@huawei.com> Reviewed-by: Vladimir Sementsov-Ogievskiy [eblake: commit message grammar tweaks] Signed-off-by: Eric Blake --- migration/block-dirty-bitmap.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c index 98921db772..c61d382be8 100644 --- a/migration/block-dirty-bitmap.c +++ b/migration/block-dirty-bitmap.c @@ -1072,18 +1072,15 @@ static int dirty_bitmap_load_header(QEMUFile *f, DBMLoadState *s, return -EINVAL; } - if (!s->cancelled) { - if (bitmap_alias_map) { - bitmap_name = g_hash_table_lookup(bitmap_alias_map, - s->bitmap_alias); - if (!bitmap_name) { - error_report("Error: Unknown bitmap alias '%s' on node " - "'%s' (alias '%s')", s->bitmap_alias, - s->bs->node_name, s->node_alias); - cancel_incoming_locked(s); - } - } else { - bitmap_name = s->bitmap_alias; + bitmap_name = s->bitmap_alias; + if (!s->cancelled && bitmap_alias_map) { + bitmap_name = g_hash_table_lookup(bitmap_alias_map, + s->bitmap_alias); + if (!bitmap_name) { + error_report("Error: Unknown bitmap alias '%s' on node " + "'%s' (alias '%s')", s->bitmap_alias, + s->bs->node_name, s->node_alias); + cancel_incoming_locked(s); } }