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 55EE9C43219 for ; Mon, 18 Apr 2022 14:08:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344500AbiDROKY (ORCPT ); Mon, 18 Apr 2022 10:10:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343853AbiDRNy2 (ORCPT ); Mon, 18 Apr 2022 09:54:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98C12488A8; Mon, 18 Apr 2022 06:03:49 -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 ams.source.kernel.org (Postfix) with ESMTPS id 41FBBB80D9C; Mon, 18 Apr 2022 13:03:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E378C385A8; Mon, 18 Apr 2022 13:03:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650287027; bh=A3BNRBlacHVDYbewZiH+BeNJRgRoXRk4/8nI2tf049M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jVu28YEOfK1MDEjOBd+1/yQRPpPyR73a0jumxCEDzQqpRBSfNB9LwvqS6Xz/Aze1j Q1x6W94NBHYps6X71Gelu6dW/rVghxLkbtideKC0NRhjinGOWx1/qTo+nbW3WzB+YA 8N3jRB7ag0MNt+FjedNQbReKnFiBC0VDMuW0quTo= 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 4.9 004/218] virtio_console: break out of buf poll on remove Date: Mon, 18 Apr 2022 14:11:10 +0200 Message-Id: <20220418121158.878641130@linuxfoundation.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220418121158.636999985@linuxfoundation.org> References: <20220418121158.636999985@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 2632b0fdb1b5..a6b6dc204c1f 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -2004,6 +2004,13 @@ 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