From patchwork Tue Sep 5 14:50:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13374518 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 AAB23C83F33 for ; Tue, 5 Sep 2023 14:51:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qdXO2-0006lR-Ns; Tue, 05 Sep 2023 10:50:38 -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 1qdXO1-0006ja-U0 for qemu-devel@nongnu.org; Tue, 05 Sep 2023 10:50:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qdXNx-0004a6-Vr for qemu-devel@nongnu.org; Tue, 05 Sep 2023 10:50:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693925433; 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=X1cBct2M5bi4XJf7Jy2dSFiLcImzGX3D4bnaCCQAnho=; b=I7btzfkXxg1M0IiAYjCll2Vc5AUKCATjGksml5jtSYqDdXTS2oEz7g4mRlWJdAqGLfOViY PQDzjSQ1y6a+vHUvUk1CV3UZoXamgH76UhwJV3LOuX+fMRlB/hrHjVc+0TU7N+1bGwRFxJ pFbJhIrJQVKdS/FG+x0ueqPWN/pL4Ck= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-261-_1iEhDumNqSjq4oDV2LbTA-1; Tue, 05 Sep 2023 10:50:30 -0400 X-MC-Unique: _1iEhDumNqSjq4oDV2LbTA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5BAE13C0DDBC; Tue, 5 Sep 2023 14:50:27 +0000 (UTC) Received: from merkur.redhat.com (unknown [10.39.194.195]) by smtp.corp.redhat.com (Postfix) with ESMTP id DB0BD46F523; Tue, 5 Sep 2023 14:50:25 +0000 (UTC) From: Kevin Wolf To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, mst@redhat.com, quintela@redhat.com, peterx@redhat.com, leobras@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, qemu-block@nongnu.org, qemu-stable@nongnu.org Subject: [PATCH 2/2] virtio: Drop out of coroutine context in virtio_load() Date: Tue, 5 Sep 2023 16:50:02 +0200 Message-ID: <20230905145002.46391-3-kwolf@redhat.com> In-Reply-To: <20230905145002.46391-1-kwolf@redhat.com> References: <20230905145002.46391-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org virtio_load() as a whole should run in coroutine context because it reads from the migration stream and we don't want this to block. However, it calls virtio_set_features_nocheck() and devices don't expect their .set_features callback to run in a coroutine and therefore call functions that may not be called in coroutine context. To fix this, drop out of coroutine context for calling virtio_set_features_nocheck(). Without this fix, the following crash was reported: #0 __pthread_kill_implementation (threadid=, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44 #1 0x00007efc738c05d3 in __pthread_kill_internal (signo=6, threadid=) at pthread_kill.c:78 #2 0x00007efc73873d26 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26 #3 0x00007efc738477f3 in __GI_abort () at abort.c:79 #4 0x00007efc7384771b in __assert_fail_base (fmt=0x7efc739dbcb8 "", assertion=assertion@entry=0x560aebfbf5cf "!qemu_in_coroutine()", file=file@entry=0x560aebfcd2d4 "../block/graph-lock.c", line=line@entry=275, function=function@entry=0x560aebfcd34d "void bdrv_graph_rdlock_main_loop(void)") at assert.c:92 #5 0x00007efc7386ccc6 in __assert_fail (assertion=0x560aebfbf5cf "!qemu_in_coroutine()", file=0x560aebfcd2d4 "../block/graph-lock.c", line=275, function=0x560aebfcd34d "void bdrv_graph_rdlock_main_loop(void)") at assert.c:101 #6 0x0000560aebcd8dd6 in bdrv_register_buf () #7 0x0000560aeb97ed97 in ram_block_added.llvm () #8 0x0000560aebb8303f in ram_block_add.llvm () #9 0x0000560aebb834fa in qemu_ram_alloc_internal.llvm () #10 0x0000560aebb2ac98 in vfio_region_mmap () #11 0x0000560aebb3ea0f in vfio_bars_register () #12 0x0000560aebb3c628 in vfio_realize () #13 0x0000560aeb90f0c2 in pci_qdev_realize () #14 0x0000560aebc40305 in device_set_realized () #15 0x0000560aebc48e07 in property_set_bool.llvm () #16 0x0000560aebc46582 in object_property_set () #17 0x0000560aebc4cd58 in object_property_set_qobject () #18 0x0000560aebc46ba7 in object_property_set_bool () #19 0x0000560aeb98b3ca in qdev_device_add_from_qdict () #20 0x0000560aebb1fbaf in virtio_net_set_features () #21 0x0000560aebb46b51 in virtio_set_features_nocheck () #22 0x0000560aebb47107 in virtio_load () #23 0x0000560aeb9ae7ce in vmstate_load_state () #24 0x0000560aeb9d2ee9 in qemu_loadvm_state_main () #25 0x0000560aeb9d45e1 in qemu_loadvm_state () #26 0x0000560aeb9bc32c in process_incoming_migration_co.llvm () #27 0x0000560aebeace56 in coroutine_trampoline.llvm () Cc: qemu-stable@nongnu.org Buglink: https://issues.redhat.com/browse/RHEL-832 Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi --- hw/virtio/virtio.c | 45 ++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 40 insertions(+), 5 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 309038fd46..969c25f4cf 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2825,8 +2825,9 @@ static int virtio_device_put(QEMUFile *f, void *opaque, size_t size, } /* A wrapper for use as a VMState .get function */ -static int virtio_device_get(QEMUFile *f, void *opaque, size_t size, - const VMStateField *field) +static int coroutine_mixed_fn +virtio_device_get(QEMUFile *f, void *opaque, size_t size, + const VMStateField *field) { VirtIODevice *vdev = VIRTIO_DEVICE(opaque); DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev)); @@ -2853,6 +2854,39 @@ static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val) return bad ? -1 : 0; } +typedef struct VirtioSetFeaturesNocheckData { + Coroutine *co; + VirtIODevice *vdev; + uint64_t val; + int ret; +} VirtioSetFeaturesNocheckData; + +static void virtio_set_features_nocheck_bh(void *opaque) +{ + VirtioSetFeaturesNocheckData *data = opaque; + + data->ret = virtio_set_features_nocheck(data->vdev, data->val); + aio_co_wake(data->co); +} + +static int coroutine_mixed_fn +virtio_set_features_nocheck_maybe_co(VirtIODevice *vdev, uint64_t val) +{ + if (qemu_in_coroutine()) { + VirtioSetFeaturesNocheckData data = { + .co = qemu_coroutine_self(), + .vdev = vdev, + .val = val, + }; + aio_bh_schedule_oneshot(qemu_get_current_aio_context(), + virtio_set_features_nocheck_bh, &data); + qemu_coroutine_yield(); + return data.ret; + } else { + return virtio_set_features_nocheck(vdev, val); + } +} + int virtio_set_features(VirtIODevice *vdev, uint64_t val) { int ret; @@ -2906,7 +2940,8 @@ size_t virtio_get_config_size(const VirtIOConfigSizeParams *params, return config_size; } -int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) +int coroutine_mixed_fn +virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) { int i, ret; int32_t config_len; @@ -3023,14 +3058,14 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) * host_features. */ uint64_t features64 = vdev->guest_features; - if (virtio_set_features_nocheck(vdev, features64) < 0) { + if (virtio_set_features_nocheck_maybe_co(vdev, features64) < 0) { error_report("Features 0x%" PRIx64 " unsupported. " "Allowed features: 0x%" PRIx64, features64, vdev->host_features); return -1; } } else { - if (virtio_set_features_nocheck(vdev, features) < 0) { + if (virtio_set_features_nocheck_maybe_co(vdev, features) < 0) { error_report("Features 0x%x unsupported. " "Allowed features: 0x%" PRIx64, features, vdev->host_features);