From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB4E3C433F5 for ; Mon, 18 Apr 2022 13:33:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242589AbiDRNfU (ORCPT ); Mon, 18 Apr 2022 09:35:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242736AbiDRNJZ (ORCPT ); Mon, 18 Apr 2022 09:09:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA75536333; Mon, 18 Apr 2022 05:48:56 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D404F6124A; Mon, 18 Apr 2022 12:48:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD619C385A1; Mon, 18 Apr 2022 12:48:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650286131; bh=pbmnvJMpAqebIetUAqMQen3WmrQy0z43KJeIZmjeLA8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B0QQvd1Fu7t/wWCaQZstufk384vwW7hIvovbYzCAfvABSRnIO6UXBq/XV9JgHI+Qi FhXqyQlwDnoVrf5dJPQ8jsJk+AW43pIrqzGXyCqVnlU7dItWBcwVCewW9f1Ea6dzYb uxEwJABpZqJk0OUR/CwwFg3MdaAmhMDEEG8jb7Gg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 4.14 004/284] virtio_console: break out of buf poll on remove Date: Mon, 18 Apr 2022 14:09:45 +0200 Message-Id: <20220418121210.819571886@linuxfoundation.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220418121210.689577360@linuxfoundation.org> References: <20220418121210.689577360@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael S. Tsirkin [ Upstream commit 0e7174b9d5877130fec41fb4a16e0c2ee4958d44 ] A common pattern for device reset is currently: vdev->config->reset(vdev); .. cleanup .. reset prevents new interrupts from arriving and waits for interrupt handlers to finish. However if - as is common - the handler queues a work request which is flushed during the cleanup stage, we have code adding buffers / trying to get buffers while device is reset. Not good. This was reproduced by running modprobe virtio_console modprobe -r virtio_console in a loop. Fix this up by calling virtio_break_device + flush before reset. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1786239 Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin --- drivers/char/virtio_console.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 0fb3a8e62e62..2140d401523f 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -2001,6 +2001,13 @@ static void virtcons_remove(struct virtio_device *vdev) list_del(&portdev->list); spin_unlock_irq(&pdrvdata_lock); + /* Device is going away, exit any polling for buffers */ + virtio_break_device(vdev); + if (use_multiport(portdev)) + flush_work(&portdev->control_work); + else + flush_work(&portdev->config_work); + /* Disable interrupts for vqs */ vdev->config->reset(vdev); /* Finish up work that's lined up */ -- 2.34.1