* [PULL 1/2] migration/block-dirty-bitmap: fix larger granularity bitmaps
2020-10-26 12:02 [PULL 0/2] bitmaps patches for 2020-10-26 Eric Blake
@ 2020-10-26 12:02 ` Eric Blake
2020-10-26 12:02 ` [PULL 2/2] migration/block-dirty-bitmap: fix uninitialized variable warning Eric Blake
2020-10-27 10:25 ` [PULL 0/2] bitmaps patches for 2020-10-26 Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Eric Blake @ 2020-10-26 12:02 UTC (permalink / raw)
To: qemu-devel
Cc: Fam Zheng, Vladimir Sementsov-Ogievskiy, open list:Dirty Bitmaps,
Juan Quintela, Stefan Reiter, Dr. David Alan Gilbert,
Stefan Hajnoczi, John Snow
From: Stefan Reiter <s.reiter@proxmox.com>
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>
---
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 5bef793ac0eb..98921db77271 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;
}
--
2.29.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PULL 2/2] migration/block-dirty-bitmap: fix uninitialized variable warning
2020-10-26 12:02 [PULL 0/2] bitmaps patches for 2020-10-26 Eric Blake
2020-10-26 12:02 ` [PULL 1/2] migration/block-dirty-bitmap: fix larger granularity bitmaps Eric Blake
@ 2020-10-26 12:02 ` Eric Blake
2020-10-27 10:25 ` [PULL 0/2] bitmaps patches for 2020-10-26 Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Eric Blake @ 2020-10-26 12:02 UTC (permalink / raw)
To: qemu-devel
Cc: Fam Zheng, Vladimir Sementsov-Ogievskiy, open list:Dirty Bitmaps,
Juan Quintela, Dr. David Alan Gilbert, Stefan Hajnoczi,
Euler Robot, Chen Qun, John Snow
From: Chen Qun <kuhn.chenqun@huawei.com>
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 <euler.robot@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
Message-Id: <20201014114430.1898684-1-kuhn.chenqun@huawei.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: commit message grammar tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
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 98921db77271..c61d382be87c 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);
}
}
--
2.29.0
^ permalink raw reply related [flat|nested] 4+ messages in thread