From patchwork Mon Sep 5 18:13:45 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 9315049 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5E8C360760 for ; Mon, 5 Sep 2016 18:51:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5322928A33 for ; Mon, 5 Sep 2016 18:51:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 47DC228AB5; Mon, 5 Sep 2016 18:51:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E363228A33 for ; Mon, 5 Sep 2016 18:51:11 +0000 (UTC) Received: from localhost ([::1]:56341 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bgyz9-0000B1-2F for patchwork-qemu-devel@patchwork.kernel.org; Mon, 05 Sep 2016 14:51:11 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38622) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bgyQ1-0003LY-Lc for qemu-devel@nongnu.org; Mon, 05 Sep 2016 14:14:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bgyPz-0001Al-Hd for qemu-devel@nongnu.org; Mon, 05 Sep 2016 14:14:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55542) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bgyPm-000149-S2; Mon, 05 Sep 2016 14:14:39 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (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 8A2C183F46; Mon, 5 Sep 2016 18:14:38 +0000 (UTC) Received: from noname.redhat.com (ovpn-116-62.ams2.redhat.com [10.36.116.62]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u85IDt7v020627; Mon, 5 Sep 2016 14:14:37 -0400 From: Kevin Wolf To: qemu-block@nongnu.org Date: Mon, 5 Sep 2016 20:13:45 +0200 Message-Id: <1473099234-10882-34-git-send-email-kwolf@redhat.com> In-Reply-To: <1473099234-10882-1-git-send-email-kwolf@redhat.com> References: <1473099234-10882-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 05 Sep 2016 18:14:38 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 33/42] coroutine: Assert that no locks are held on termination X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP A coroutine that takes a lock must also release it again. If the coroutine terminates without having released all its locks, it's buggy and we'll probably run into a deadlock sooner or later. Make sure that we don't get such cases. Signed-off-by: Kevin Wolf Reviewed-by: Paolo Bonzini Reviewed-by: Stefan Hajnoczi --- include/qemu/coroutine_int.h | 1 + util/qemu-coroutine-lock.c | 11 +++++++++++ util/qemu-coroutine.c | 1 + 3 files changed, 13 insertions(+) diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h index 581a7f5..6df9d33 100644 --- a/include/qemu/coroutine_int.h +++ b/include/qemu/coroutine_int.h @@ -39,6 +39,7 @@ struct Coroutine { void *entry_arg; Coroutine *caller; QSLIST_ENTRY(Coroutine) pool_next; + size_t locks_held; /* Coroutines that should be woken up when we yield or terminate */ QSIMPLEQ_HEAD(, Coroutine) co_queue_wakeup; diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c index f30ee81..14cf9ce 100644 --- a/util/qemu-coroutine-lock.c +++ b/util/qemu-coroutine-lock.c @@ -130,6 +130,7 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex) mutex->locked = true; mutex->holder = self; + self->locks_held++; trace_qemu_co_mutex_lock_return(mutex, self); } @@ -146,6 +147,7 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex) mutex->locked = false; mutex->holder = NULL; + self->locks_held--; qemu_co_queue_next(&mutex->queue); trace_qemu_co_mutex_unlock_return(mutex, self); @@ -159,14 +161,19 @@ void qemu_co_rwlock_init(CoRwlock *lock) void qemu_co_rwlock_rdlock(CoRwlock *lock) { + Coroutine *self = qemu_coroutine_self(); + while (lock->writer) { qemu_co_queue_wait(&lock->queue); } lock->reader++; + self->locks_held++; } void qemu_co_rwlock_unlock(CoRwlock *lock) { + Coroutine *self = qemu_coroutine_self(); + assert(qemu_in_coroutine()); if (lock->writer) { lock->writer = false; @@ -179,12 +186,16 @@ void qemu_co_rwlock_unlock(CoRwlock *lock) qemu_co_queue_next(&lock->queue); } } + self->locks_held--; } void qemu_co_rwlock_wrlock(CoRwlock *lock) { + Coroutine *self = qemu_coroutine_self(); + while (lock->writer || lock->reader) { qemu_co_queue_wait(&lock->queue); } lock->writer = true; + self->locks_held++; } diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c index 89f21a9..3cbf225 100644 --- a/util/qemu-coroutine.c +++ b/util/qemu-coroutine.c @@ -122,6 +122,7 @@ void qemu_coroutine_enter(Coroutine *co) case COROUTINE_YIELD: return; case COROUTINE_TERMINATE: + assert(!co->locks_held); trace_qemu_coroutine_terminate(co); coroutine_delete(co); return;