From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38655) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXUoK-0008M2-PZ for qemu-devel@nongnu.org; Mon, 25 Jun 2018 12:57:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fXUoI-0006s4-QL for qemu-devel@nongnu.org; Mon, 25 Jun 2018 12:57:52 -0400 From: Vladimir Sementsov-Ogievskiy Date: Mon, 25 Jun 2018 19:57:45 +0300 Message-Id: <20180625165745.25259-3-vsementsov@virtuozzo.com> In-Reply-To: <20180625165745.25259-1-vsementsov@virtuozzo.com> References: <20180625165745.25259-1-vsementsov@virtuozzo.com> Subject: [Qemu-devel] [PATCH 2/2] dirty-bitmap: fix double lock on bitmap enabling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: dgilbert@redhat.com, quintela@redhat.com, stefanha@redhat.com, mreitz@redhat.com, kwolf@redhat.com, jsnow@redhat.com, famz@redhat.com, vsementsov@virtuozzo.com, den@openvz.org 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 --- 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); -- 2.11.1