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 X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B71AC2BB85 for ; Thu, 16 Apr 2020 13:01:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48995214AF for ; Thu, 16 Apr 2020 13:01:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587042095; bh=42XYOGO8K60P5I62HXrT0Is11P1/mgtaFZh5cAvbk6U=; h=Subject:To:From:Date:List-ID:From; b=B2F9WcZUzPPGW0LWESTOFwfbl0+mc4MR0zwbWkklv/MYG4DtAdffyM0BIkVyjV9pW nCOv5c1K8+ufNNrpwGLbu0CdQXLWNRvlWYLcabEmlamNRvQxi2uPi47UERI49j17c1 Da/7zs8LBdCHaN5MY9A7oUOitJNbN5fxllP1Y9uQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2894688AbgDPNBb (ORCPT ); Thu, 16 Apr 2020 09:01:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:38590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2894706AbgDPNBT (ORCPT ); Thu, 16 Apr 2020 09:01:19 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AD83221D79; Thu, 16 Apr 2020 13:01:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587042077; bh=42XYOGO8K60P5I62HXrT0Is11P1/mgtaFZh5cAvbk6U=; h=Subject:To:From:Date:From; b=yjrLYbVQG34jL+xT3S8jn43Hu4JBw1utAmG0VjgbJwinTMXsWqd0gUO2KlFSDbja1 PCMdOT797Eox/QmNspiJH6+14HdjkBIhfW0Q3E4Kfpeu8B4qWhi4haPC9XsRfTR/tr WdSYT6Z5rjE2r8MwlkS/Z0Ll3N1dRG+eMwnaFiJo= Subject: patch "UAS: fix deadlock in error handling and PM flushing work" added to usb-linus To: oneukum@suse.com, gregkh@linuxfoundation.org, stable@vger.kernel.org From: Date: Thu, 16 Apr 2020 15:01:02 +0200 Message-ID: <1587042062245118@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled UAS: fix deadlock in error handling and PM flushing work to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From f6cc6093a729ede1ff5658b493237c42b82ba107 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 15 Apr 2020 16:17:50 +0200 Subject: UAS: fix deadlock in error handling and PM flushing work A SCSI error handler and block runtime PM must not allocate memory with GFP_KERNEL. Furthermore they must not wait for tasks allocating memory with GFP_KERNEL. That means that they cannot share a workqueue with arbitrary tasks. Fix this for UAS using a private workqueue. Signed-off-by: Oliver Neukum Fixes: f9dc024a2da1f ("uas: pre_reset and suspend: Fix a few races") Cc: stable Link: https://lore.kernel.org/r/20200415141750.811-2-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/storage/uas.c | 43 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 40 insertions(+), 3 deletions(-) diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c index 08503e3507bf..d592071119ba 100644 --- a/drivers/usb/storage/uas.c +++ b/drivers/usb/storage/uas.c @@ -81,6 +81,19 @@ static void uas_free_streams(struct uas_dev_info *devinfo); static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *prefix, int status); +/* + * This driver needs its own workqueue, as we need to control memory allocation. + * + * In the course of error handling and power management uas_wait_for_pending_cmnds() + * needs to flush pending work items. In these contexts we cannot allocate memory + * by doing block IO as we would deadlock. For the same reason we cannot wait + * for anything allocating memory not heeding these constraints. + * + * So we have to control all work items that can be on the workqueue we flush. + * Hence we cannot share a queue and need our own. + */ +static struct workqueue_struct *workqueue; + static void uas_do_work(struct work_struct *work) { struct uas_dev_info *devinfo = @@ -109,7 +122,7 @@ static void uas_do_work(struct work_struct *work) if (!err) cmdinfo->state &= ~IS_IN_WORK_LIST; else - schedule_work(&devinfo->work); + queue_work(workqueue, &devinfo->work); } out: spin_unlock_irqrestore(&devinfo->lock, flags); @@ -134,7 +147,7 @@ static void uas_add_work(struct uas_cmd_info *cmdinfo) lockdep_assert_held(&devinfo->lock); cmdinfo->state |= IS_IN_WORK_LIST; - schedule_work(&devinfo->work); + queue_work(workqueue, &devinfo->work); } static void uas_zap_pending(struct uas_dev_info *devinfo, int result) @@ -1229,7 +1242,31 @@ static struct usb_driver uas_driver = { .id_table = uas_usb_ids, }; -module_usb_driver(uas_driver); +static int __init uas_init(void) +{ + int rv; + + workqueue = alloc_workqueue("uas", WQ_MEM_RECLAIM, 0); + if (!workqueue) + return -ENOMEM; + + rv = usb_register(&uas_driver); + if (rv) { + destroy_workqueue(workqueue); + return -ENOMEM; + } + + return 0; +} + +static void __exit uas_exit(void) +{ + usb_deregister(&uas_driver); + destroy_workqueue(workqueue); +} + +module_init(uas_init); +module_exit(uas_exit); MODULE_LICENSE("GPL"); MODULE_IMPORT_NS(USB_STORAGE); -- 2.26.1