From patchwork Mon Mar 21 21:41:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 12787798 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 B9E69C433F5 for ; Mon, 21 Mar 2022 21:47:18 +0000 (UTC) Received: from localhost ([::1]:58194 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nWPrx-0002vc-Mp for qemu-devel@archiver.kernel.org; Mon, 21 Mar 2022 17:47:17 -0400 Received: from eggs.gnu.org ([209.51.188.92]:54872) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWPmk-00050k-9Z for qemu-devel@nongnu.org; Mon, 21 Mar 2022 17:41:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:29620) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWPmf-0006M5-UW for qemu-devel@nongnu.org; Mon, 21 Mar 2022 17:41:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647898906; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YFUkW4449ePvuDQ+5BOXtvf2hWWsWgUMixtARwJpjXE=; b=aysUvwkaSPdjZn2d8ZEFMpruy6ScPaoSqrdeFOohwmIt5oiVISZflAIkBkX9JUdCC4q/A4 erv6A4hHzBbaxahGXgwXF6H3wKXhTs059ln9coO61zCJ+HvFXAE8H62cUmrm79ce3mnth4 iohWfpk3/PGUoIqiYIdf20R5varWeNo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-393-LHo12okxMlWJEK7_HXbzUg-1; Mon, 21 Mar 2022 17:41:43 -0400 X-MC-Unique: LHo12okxMlWJEK7_HXbzUg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 727C4851785; Mon, 21 Mar 2022 21:41:40 +0000 (UTC) Received: from blue.redhat.com (unknown [10.2.16.194]) by smtp.corp.redhat.com (Postfix) with ESMTP id C7D9344198F; Mon, 21 Mar 2022 21:41:38 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Subject: [PULL 3/3] block/nbd.c: Fixed IO request coroutine not being wakeup when kill NBD server Date: Mon, 21 Mar 2022 16:41:34 -0500 Message-Id: <20220321214134.597006-4-eblake@redhat.com> In-Reply-To: <20220321214134.597006-1-eblake@redhat.com> References: <20220321214134.597006-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , "open list:Network Block Dev..." , Rao Lei , Hanna Reitz , Vladimir Sementsov-Ogievskiy Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Rao Lei During the IO stress test, the IO request coroutine has a probability that is can't be awakened when the NBD server is killed. The GDB stack is as follows: (gdb) bt 0 0x00007f2ff990cbf6 in __ppoll (fds=0x55575de85000, nfds=1, timeout=, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:44 1 0x000055575c302e7c in qemu_poll_ns (fds=0x55575de85000, nfds=1, timeout=599999603140) at ../util/qemu-timer.c:348 2 0x000055575c2d3c34 in fdmon_poll_wait (ctx=0x55575dc480f0, ready_list=0x7ffd9dd1dae0, timeout=599999603140) at ../util/fdmon-poll.c:80 3 0x000055575c2d350d in aio_poll (ctx=0x55575dc480f0, blocking=true) at ../util/aio-posix.c:655 4 0x000055575c16eabd in bdrv_do_drained_begin(bs=0x55575dee7fe0, recursive=false, parent=0x0, ignore_bds_parents=false, poll=true)at ../block/io.c:474 5 0x000055575c16eba6 in bdrv_drained_begin (bs=0x55575dee7fe0) at ../block/io.c:480 6 0x000055575c1aff33 in quorum_del_child (bs=0x55575dee7fe0, child=0x55575dcea690, errp=0x7ffd9dd1dd08) at ../block/quorum.c:1130 7 0x000055575c14239b in bdrv_del_child (parent_bs=0x55575dee7fe0, child=0x55575dcea690, errp=0x7ffd9dd1dd08) at ../block.c:7705 8 0x000055575c12da28 in qmp_x_blockdev_change(parent=0x55575df404c0 "colo-disk0", has_child=true, child=0x55575de867f0 "children.1", has_node=false, no de=0x0, errp=0x7ffd9dd1dd08) at ../blockdev.c:3676 9 0x000055575c258435 in qmp_marshal_x_blockdev_change (args=0x7f2fec008190, ret=0x7f2ff7b0bd98, errp=0x7f2ff7b0bd90) at qapi/qapi-commands-block-core.c :1675 10 0x000055575c2c6201 in do_qmp_dispatch_bh (opaque=0x7f2ff7b0be30) at ../qapi/qmp-dispatch.c:129 11 0x000055575c2ebb1c in aio_bh_call (bh=0x55575dc429c0) at ../util/async.c:141 12 0x000055575c2ebc2a in aio_bh_poll (ctx=0x55575dc480f0) at ../util/async.c:169 13 0x000055575c2d2d96 in aio_dispatch (ctx=0x55575dc480f0) at ../util/aio-posix.c:415 14 0x000055575c2ec07f in aio_ctx_dispatch (source=0x55575dc480f0, callback=0x0, user_data=0x0) at ../util/async.c:311 15 0x00007f2ff9e7cfbd in g_main_context_dispatch () at /lib/x86_64-linux-gnu/libglib-2.0.so.0 16 0x000055575c2fd581 in glib_pollfds_poll () at ../util/main-loop.c:232 17 0x000055575c2fd5ff in os_host_main_loop_wait (timeout=0) at ../util/main-loop.c:255 18 0x000055575c2fd710 in main_loop_wait (nonblocking=0) at ../util/main-loop.c:531 19 0x000055575bfa7588 in qemu_main_loop () at ../softmmu/runstate.c:726 20 0x000055575bbee57a in main (argc=60, argv=0x7ffd9dd1e0e8, envp=0x7ffd9dd1e2d0) at ../softmmu/main.c:50 (gdb) qemu coroutine 0x55575e16aac0 0 0x000055575c2ee7dc in qemu_coroutine_switch (from_=0x55575e16aac0, to_=0x7f2ff830fba0, action=COROUTINE_YIELD) at ../util/coroutine-ucontext.c:302 1 0x000055575c2fe2a9 in qemu_coroutine_yield () at ../util/qemu-coroutine.c:195 2 0x000055575c2fe93c in qemu_co_queue_wait_impl (queue=0x55575dc46170, lock=0x7f2b32ad9850) at ../util/qemu-coroutine-lock.c:56 3 0x000055575c17ddfb in nbd_co_send_request (bs=0x55575ebfaf20, request=0x7f2b32ad9920, qiov=0x55575dfc15d8) at ../block/nbd.c:478 4 0x000055575c17f931 in nbd_co_request (bs=0x55575ebfaf20, request=0x7f2b32ad9920, write_qiov=0x55575dfc15d8) at ../block/nbd.c:1182 5 0x000055575c17fe14 in nbd_client_co_pwritev (bs=0x55575ebfaf20, offset=403487858688, bytes=4538368, qiov=0x55575dfc15d8, flags=0) at ../block/nbd.c:1284 6 0x000055575c170d25 in bdrv_driver_pwritev (bs=0x55575ebfaf20, offset=403487858688, bytes=4538368, qiov=0x55575dfc15d8, qiov_offset=0, flags=0) at ../block/io.c:1264 7 0x000055575c1733b4 in bdrv_aligned_pwritev (child=0x55575dff6890, req=0x7f2b32ad9ad0, offset=403487858688, bytes=4538368, align=1, qiov=0x55575dfc15d8, qiov_offset=0, flags=0) at ../block/io.c:2126 8 0x000055575c173c67 in bdrv_co_pwritev_part (child=0x55575dff6890, offset=403487858688, bytes=4538368, qiov=0x55575dfc15d8, qiov_offset=0, flags=0) at ../block/io.c:2314 9 0x000055575c17391b in bdrv_co_pwritev (child=0x55575dff6890, offset=403487858688, bytes=4538368, qiov=0x55575dfc15d8, flags=0) at ../block/io.c:2233 10 0x000055575c1ee506 in replication_co_writev (bs=0x55575e9824f0, sector_num=788062224, remaining_sectors=8864, qiov=0x55575dfc15d8, flags=0) at ../block/replication.c:270 11 0x000055575c170eed in bdrv_driver_pwritev (bs=0x55575e9824f0, offset=403487858688, bytes=4538368, qiov=0x55575dfc15d8, qiov_offset=0, flags=0) at ../block/io.c:1297 12 0x000055575c1733b4 in bdrv_aligned_pwritev (child=0x55575dcea690, req=0x7f2b32ad9e00, offset=403487858688, bytes=4538368, align=512, qiov=0x55575dfc15d8, qiov_offset=0, flags=0) at ../block/io.c:2126 13 0x000055575c173c67 in bdrv_co_pwritev_part (child=0x55575dcea690, offset=403487858688, bytes=4538368, qiov=0x55575dfc15d8, qiov_offset=0, flags=0) at ../block/io.c:2314 14 0x000055575c17391b in bdrv_co_pwritev (child=0x55575dcea690, offset=403487858688, bytes=4538368, qiov=0x55575dfc15d8, flags=0) at ../block/io.c:2233 15 0x000055575c1aeffa in write_quorum_entry (opaque=0x7f2fddaf8c50) at ../block/quorum.c:699 16 0x000055575c2ee4db in coroutine_trampoline (i0=1578543808, i1=21847) at ../util/coroutine-ucontext.c:173 17 0x00007f2ff9855660 in __start_context () at ../sysdeps/unix/sysv/linux/x86_64/__start_context.S:91 When we do failover in COLO mode, QEMU will hang while it is waiting for the in-flight IO. From the call trace, we can see the IO request coroutine has yielded in nbd_co_send_request(). When we kill the NBD server, it will never be wake up. Actually, when we do IO stress test, it will have a lot of requests in free_sema queue. When the NBD server is killed, current MAX_NBD_REQUESTS finishes with errors but they wake up at most MAX_NBD_REQEUSTS from the queue. So, let's move qemu_co_queue_next out to fix this issue. Signed-off-by: Lei Rao Message-Id: <20220309074844.275450-1-lei.rao@intel.com> Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Eric Blake --- block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index 34b9429de387..567872ac5338 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -533,8 +533,8 @@ err: if (i != -1) { s->requests[i].coroutine = NULL; s->in_flight--; - qemu_co_queue_next(&s->free_sema); } + qemu_co_queue_next(&s->free_sema); } qemu_co_mutex_unlock(&s->send_mutex); return rc;