From patchwork Fri Nov 20 04:39:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Finn Thain X-Patchwork-Id: 11919465 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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 EDE48C56201 for ; Fri, 20 Nov 2020 04:51:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99D5C223AC for ; Fri, 20 Nov 2020 04:51:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726325AbgKTEvj (ORCPT ); Thu, 19 Nov 2020 23:51:39 -0500 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:52650 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726172AbgKTEvg (ORCPT ); Thu, 19 Nov 2020 23:51:36 -0500 Received: by kvm5.telegraphics.com.au (Postfix, from userid 502) id A38082A451; Thu, 19 Nov 2020 23:51:35 -0500 (EST) To: Michael Schmitz , "James E.J. Bottomley" , "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Message-Id: From: Finn Thain Subject: [PATCH] scsi/atari_scsi: Fix race condition between .queuecommand and EH Date: Fri, 20 Nov 2020 15:39:56 +1100 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org It is possible that bus_reset_cleanup() or .eh_abort_handler could be invoked during NCR5380_queuecommand(). If that takes place before the new command is enqueued and after the ST-DMA "lock" has been acquired, the ST-DMA "lock" will be released again. This will result in a lost DMA interrupt and a command timeout. Fix this by excluding EH and interrupt handlers while the new command is enqueued. Signed-off-by: Finn Thain Reviewed-by: Michael Schmitz Tested-by: Michael Schmitz --- Michael, would you please send your Acked-by or Reviewed-and-tested-by? These two patches taken together should be equivalent to the one you tested recently. I've split it into two as that seemed to make more sense. --- drivers/scsi/NCR5380.c | 9 ++++++--- drivers/scsi/atari_scsi.c | 10 +++------- 2 files changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c index d654a6cc4162..ea4b5749e7da 100644 --- a/drivers/scsi/NCR5380.c +++ b/drivers/scsi/NCR5380.c @@ -580,11 +580,14 @@ static int NCR5380_queue_command(struct Scsi_Host *instance, cmd->result = 0; - if (!NCR5380_acquire_dma_irq(instance)) - return SCSI_MLQUEUE_HOST_BUSY; - spin_lock_irqsave(&hostdata->lock, flags); + if (!NCR5380_acquire_dma_irq(instance)) { + spin_unlock_irqrestore(&hostdata->lock, flags); + + return SCSI_MLQUEUE_HOST_BUSY; + } + /* * Insert the cmd into the issue queue. Note that REQUEST SENSE * commands are added to the head of the queue since any command will diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c index a82b63a66635..95d7a3586083 100644 --- a/drivers/scsi/atari_scsi.c +++ b/drivers/scsi/atari_scsi.c @@ -376,15 +376,11 @@ static int falcon_get_lock(struct Scsi_Host *instance) if (IS_A_TT()) return 1; - if (stdma_is_locked_by(scsi_falcon_intr) && - instance->hostt->can_queue > 1) + if (stdma_is_locked_by(scsi_falcon_intr)) return 1; - if (in_interrupt()) - return stdma_try_lock(scsi_falcon_intr, instance); - - stdma_lock(scsi_falcon_intr, instance); - return 1; + /* stdma_lock() may sleep which means it can't be used here */ + return stdma_try_lock(scsi_falcon_intr, instance); } #ifndef MODULE