From 58f72b965e9e1820d246329461216c4d13140122 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Wed, 4 Jul 2018 02:12:49 -0400 Subject: [PATCH] dirty-bitmap: fix double lock on bitmap enabling Bitmap lock/unlock were added to bdrv_enable_dirty_bitmap in 8b1402ce80d, but some places were not updated correspondingly, which leads to trying to take this lock twice, which is dead-lock. Fix this. Actually, iotest 199 (about dirty bitmap postcopy migration) is broken now, and this fixes it. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-id: 20180625165745.25259-3-vsementsov@virtuozzo.com Signed-off-by: John Snow --- block/dirty-bitmap.c | 3 ++- migration/block-dirty-bitmap.c | 4 ++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index 93744b3565..c9b8a6fd52 100644 --- a/block/dirty-bitmap.c +++ b/block/dirty-bitmap.c @@ -250,8 +250,9 @@ void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap) /* Called with BQL taken. */ void bdrv_dirty_bitmap_enable_successor(BdrvDirtyBitmap *bitmap) { + assert(bitmap->mutex == bitmap->successor->mutex); qemu_mutex_lock(bitmap->mutex); - bdrv_enable_dirty_bitmap(bitmap->successor); + bdrv_enable_dirty_bitmap_locked(bitmap->successor); qemu_mutex_unlock(bitmap->mutex); } diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c index 3bafbbdc4c..477826330c 100644 --- a/migration/block-dirty-bitmap.c +++ b/migration/block-dirty-bitmap.c @@ -511,7 +511,7 @@ void dirty_bitmap_mig_before_vm_start(void) DirtyBitmapLoadBitmapState *b = item->data; if (b->migrated) { - bdrv_enable_dirty_bitmap(b->bitmap); + bdrv_enable_dirty_bitmap_locked(b->bitmap); } else { bdrv_dirty_bitmap_enable_successor(b->bitmap); } @@ -547,7 +547,7 @@ static void dirty_bitmap_load_complete(QEMUFile *f, DirtyBitmapLoadState *s) if (enabled_bitmaps == NULL) { /* in postcopy */ bdrv_reclaim_dirty_bitmap_locked(s->bs, s->bitmap, &error_abort); - bdrv_enable_dirty_bitmap(s->bitmap); + bdrv_enable_dirty_bitmap_locked(s->bitmap); } else { /* target not started, successor must be empty */ int64_t count = bdrv_get_dirty_count(s->bitmap);