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Thu, 23 Jan 2020 16:48:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579798137; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AsLIGnsc4Kc2PIcdInCoGUfJ3yiSTnFajKGCNhtMMv0=; b=CXBDlvCo2rKBLhH/E8Zz21ZDcVLhvHBTulPLMee+QuT1OSBlE8mz1dRhIYY+4jaRYXVPSt vmT1Vjgk+acKD18gHBVjNzXjQ08LFZX7aRKZqDeTOOqB5EMvesHWEeq8yZP9cayy2PWSXv Ht24gOGgVm+I4eJLxm+J8zCM3lyibrc= From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com Subject: [PULL 107/108] virtiofsd: stop all queue threads on exit in virtio_loop() Date: Thu, 23 Jan 2020 16:46:29 +0000 Message-Id: <20200123164630.91498-108-dgilbert@redhat.com> In-Reply-To: <20200123164630.91498-1-dgilbert@redhat.com> References: <20200123164630.91498-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: NjNHBdyHOWGKJj3ZUFlPzA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" From: Eryu Guan On guest graceful shutdown, virtiofsd receives VHOST_USER_GET_VRING_BASE request from VMM and shuts down virtqueues by calling fv_set_started(), which joins fv_queue_thread() threads. So when virtio_loop() returns, there should be no thread is still accessing data in fuse session and/or virtio dev. But on abnormal exit, e.g. guest got killed for whatever reason, vhost-user socket is closed and virtio_loop() breaks out the main loop and returns to main(). But it's possible fv_queue_worker()s are still working and accessing fuse session and virtio dev, which results in crash or use-after-free. Fix it by stopping fv_queue_thread()s before virtio_loop() returns, to make sure there's no-one could access fuse session and virtio dev. Reported-by: Qingming Su Signed-off-by: Eryu Guan Reviewed-by: Stefan Hajnoczi Signed-off-by: Dr. David Alan Gilbert --- tools/virtiofsd/fuse_virtio.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index 9f6582343c..80a6e929df 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -815,6 +815,19 @@ int virtio_loop(struct fuse_session *se) } } =20 + /* + * Make sure all fv_queue_thread()s quit on exit, as we're about to + * free virtio dev and fuse session, no one should access them anymore. + */ + for (int i =3D 0; i < se->virtio_dev->nqueues; i++) { + if (!se->virtio_dev->qi[i]) { + continue; + } + + fuse_log(FUSE_LOG_INFO, "%s: Stopping queue %d thread\n", __func__= , i); + fv_queue_cleanup_thread(se->virtio_dev, i); + } + fuse_log(FUSE_LOG_INFO, "%s: Exit\n", __func__); =20 return 0; --=20 2.24.1