From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39174) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d6GMP-0005KU-Aw for qemu-devel@nongnu.org; Thu, 04 May 2017 08:59:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d6GMK-0008Ed-Gq for qemu-devel@nongnu.org; Thu, 04 May 2017 08:59:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36762) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d6GMK-0008EP-9a for qemu-devel@nongnu.org; Thu, 04 May 2017 08:59:52 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1DB8E7F40B for ; Thu, 4 May 2017 12:59:51 +0000 (UTC) References: <20170503072819.14462-1-famz@redhat.com> From: Paolo Bonzini Message-ID: <7f3ca702-7ea8-bcee-af55-71a645b7e39c@redhat.com> Date: Thu, 4 May 2017 14:59:47 +0200 MIME-Version: 1.0 In-Reply-To: <20170503072819.14462-1-famz@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] dump: Acquire BQL around vm_start() in dump thread List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , qemu-devel@nongnu.org Cc: armbru@redhat.com, peterx@redhat.com On 03/05/2017 09:28, Fam Zheng wrote: > This fixes an assertion failure in the following backtrace: > > __GI___assert_fail > memory_region_transaction_commit > memory_region_add_eventfd > virtio_pci_ioeventfd_assign > virtio_bus_set_host_notifier > virtio_blk_data_plane_start > virtio_bus_start_ioeventfd > virtio_vmstate_change > vm_state_notify > vm_prepare_start > vm_start > dump_cleanup > dump_process > dump_thread > start_thread > clone > > vm_start need BQL, acquire it if doing cleaning up from main thread. > > Signed-off-by: Fam Zheng > --- > dump.c | 7 +++++++ > include/sysemu/dump.h | 1 + > 2 files changed, 8 insertions(+) > > diff --git a/dump.c b/dump.c > index f7b80d8..d9090a2 100644 > --- a/dump.c > +++ b/dump.c > @@ -77,7 +77,13 @@ static int dump_cleanup(DumpState *s) > memory_mapping_list_free(&s->list); > close(s->fd); > if (s->resume) { > + if (s->detached) { > + qemu_mutex_lock_iothread(); > + } > vm_start(); > + if (s->detached) { > + qemu_mutex_unlock_iothread(); > + } > } > > return 0; > @@ -1804,6 +1810,7 @@ void qmp_dump_guest_memory(bool paging, const char *file, > > if (detach_p) { > /* detached dump */ > + s->detached = true; > qemu_thread_create(&s->dump_thread, "dump_thread", dump_thread, > s, QEMU_THREAD_DETACHED); > } else { > diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h > index ef931be..2672a15 100644 > --- a/include/sysemu/dump.h > +++ b/include/sysemu/dump.h > @@ -157,6 +157,7 @@ typedef struct DumpState { > uint32_t sh_info; > bool have_section; > bool resume; > + bool detached; > ssize_t note_size; > hwaddr memory_offset; > int fd; > Queued, thanks. Paolo