From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38300) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ynqn3-0003c4-4k for qemu-devel@nongnu.org; Thu, 30 Apr 2015 11:54:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ynqmz-00029e-Pl for qemu-devel@nongnu.org; Thu, 30 Apr 2015 11:54:17 -0400 Received: from mail-wg0-x235.google.com ([2a00:1450:400c:c00::235]:36575) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ynqmz-00029R-IF for qemu-devel@nongnu.org; Thu, 30 Apr 2015 11:54:13 -0400 Received: by wgen6 with SMTP id n6so67293327wge.3 for ; Thu, 30 Apr 2015 08:54:12 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <55425021.4050606@redhat.com> Date: Thu, 30 Apr 2015 17:54:09 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <55424F3C.1050209@redhat.com> In-Reply-To: <55424F3C.1050209@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Fwd: qemu drive mirror assert fault List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow , Fam Zheng , qemu-devel , wangxiaolong@ucloud.cn On 30/04/2015 17:50, Paolo Bonzini wrote: > John, Fam, > > I got this report offlist. This happens if a bit in the hbitmap is > cleared and the HBitmap has _not_ yet reached the bit. See this comment > in include/qemu/hbitmap.h: > > * Resetting bits before the current > * position of the iterator is also okay. However, concurrent > * resetting of bits can lead to unexpected behavior if the iterator > * has not yet reached those bits. > > Can you please take a look? Oh, it's related to discard. The reported pointed out later that he is using virtio-scsi and has discard=unmap enabled. Paolo