From patchwork Tue Jun 11 17:36:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13694061 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8FC42C41513 for ; Tue, 11 Jun 2024 17:39:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sH5Qo-0008W5-Dj; Tue, 11 Jun 2024 13:37:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sH5Qn-0008Vd-Bn for qemu-devel@nongnu.org; Tue, 11 Jun 2024 13:37:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sH5Ql-0008SC-Pt for qemu-devel@nongnu.org; Tue, 11 Jun 2024 13:37:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1718127431; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EDPviX5iCZw8qqN1UwxNpLLXgI2B2YRvbWcSGkLKba0=; b=OOlZGsIYps3RdC9RNaZumOl6lJ4RK2EDZv7hzzEiQBPyP+LqeuTcv00e7/rJZS+Osru7P7 OYm/vXf5ndJtPt5GCm9eFetcvTnsHpq9av7GurUpM944EGYad0ek0lqP5qtpFmod7DCIQq y9Y4vJV1kTZoFQMCTecHmaZvJLCes1o= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-128-gAvFlpdHNGCL709YToLZjg-1; Tue, 11 Jun 2024 13:37:09 -0400 X-MC-Unique: gAvFlpdHNGCL709YToLZjg-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 781C11956094; Tue, 11 Jun 2024 17:37:08 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.192.130]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id D813F19560AB; Tue, 11 Jun 2024 17:37:05 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org Subject: [PULL 2/8] Revert "monitor: use aio_co_reschedule_self()" Date: Tue, 11 Jun 2024 19:36:52 +0200 Message-ID: <20240611173658.231831-3-kwolf@redhat.com> In-Reply-To: <20240611173658.231831-1-kwolf@redhat.com> References: <20240611173658.231831-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 11 X-Spam_score: 1.1 X-Spam_bar: + X-Spam_report: (1.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.141, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Stefan Hajnoczi Commit 1f25c172f837 ("monitor: use aio_co_reschedule_self()") was a code cleanup that uses aio_co_reschedule_self() instead of open coding coroutine rescheduling. Bug RHEL-34618 was reported and Kevin Wolf identified the root cause. I missed that aio_co_reschedule_self() -> qemu_get_current_aio_context() only knows about qemu_aio_context/IOThread AioContexts and not about iohandler_ctx. It does not function correctly when going back from the iohandler_ctx to qemu_aio_context. Go back to open coding the AioContext transitions to avoid this bug. This reverts commit 1f25c172f83704e350c0829438d832384084a74d. Cc: qemu-stable@nongnu.org Buglink: https://issues.redhat.com/browse/RHEL-34618 Signed-off-by: Stefan Hajnoczi Message-ID: <20240506190622.56095-2-stefanha@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- qapi/qmp-dispatch.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c index f3488afeef..176b549473 100644 --- a/qapi/qmp-dispatch.c +++ b/qapi/qmp-dispatch.c @@ -212,7 +212,8 @@ QDict *coroutine_mixed_fn qmp_dispatch(const QmpCommandList *cmds, QObject *requ * executing the command handler so that it can make progress if it * involves an AIO_WAIT_WHILE(). */ - aio_co_reschedule_self(qemu_get_aio_context()); + aio_co_schedule(qemu_get_aio_context(), qemu_coroutine_self()); + qemu_coroutine_yield(); } monitor_set_cur(qemu_coroutine_self(), cur_mon); @@ -226,7 +227,9 @@ QDict *coroutine_mixed_fn qmp_dispatch(const QmpCommandList *cmds, QObject *requ * Move back to iohandler_ctx so that nested event loops for * qemu_aio_context don't start new monitor commands. */ - aio_co_reschedule_self(iohandler_get_aio_context()); + aio_co_schedule(iohandler_get_aio_context(), + qemu_coroutine_self()); + qemu_coroutine_yield(); } } else { /*