From patchwork Wed Sep 20 13:54:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 724788 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 C01A4CE79D5 for ; Wed, 20 Sep 2023 13:55:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236506AbjITNzU (ORCPT ); Wed, 20 Sep 2023 09:55:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236505AbjITNzM (ORCPT ); Wed, 20 Sep 2023 09:55:12 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5BD1128; Wed, 20 Sep 2023 06:54:53 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D20CAC433CA; Wed, 20 Sep 2023 13:54:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695218093; bh=QlFssTJwZYOW+1WKBmGNub7SCKcYG3kK3ZF4wcEAKIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VjYYBI1YemL0wjyJ30dK7QivyYlN+XLHL/sg4LBoQpPZATM/mBm9GpSmTTMv7MrXY pypGchKBQiqLZLdrgoQx+JUOxNSuPlaUQi7V3TmnQ1kgoLid7ARVwSlJHU8KRnAzHZ E9rj3W2Bos/VnRq6KfTT1K+H7wfTbMPli/0NN1YM9xSZkbmkeyo90gpvdeotCcYeJm bVFWjAzCknKS9vvVP4irUh1iDc+Ri9Vv1W3hBtdCRhsHth8vABkQxDiUkUmVaaSXHI uyYgw/ZfSkYXp+Mk8HVXcEHbxkPklRO8STgV8HxrJZNnJAlMMAQl7oyjzN97wXDCG+ ggj/ObDwjr2yA== From: Damien Le Moal To: linux-ide@vger.kernel.org Cc: linux-scsi@vger.kernel.org, "Martin K . Petersen" , John Garry , Rodrigo Vivi , Paul Ausbeck , Kai-Heng Feng , Joe Breuer , Geert Uytterhoeven , Chia-Lin Kao Subject: [PATCH v4 06/23] scsi: Do not attempt to rescan suspended devices Date: Wed, 20 Sep 2023 22:54:22 +0900 Message-ID: <20230920135439.929695-7-dlemoal@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230920135439.929695-1-dlemoal@kernel.org> References: <20230920135439.929695-1-dlemoal@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org scsi_rescan_device() takes a scsi device lock before executing a device handler and device driver rescan methods. Waiting for the completion of any command issued to the device by these methods will thus be done with the device lock held. As a result, there is a risk of deadlocking within the power management code if scsi_rescan_device() is called to handle a device resume with the associated scsi device not yet resumed. Avoid such situation by checking that the target scsi device is in the running state, that is, fully capable of executing commands, before proceeding with the rescan and bailout returning -EWOULDBLOCK otherwise. With this error return, the caller can retry rescaning the device after a delay. The state check is done with the device lock held and is thus safe against incoming suspend power management operations. Fixes: 6aa0365a3c85 ("ata: libata-scsi: Avoid deadlock on rescan after device resume") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Reviewed-by: Niklas Cassel --- drivers/scsi/scsi_scan.c | 18 +++++++++++++++++- include/scsi/scsi_host.h | 2 +- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 52014b2d39e1..3db4d31a03a1 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -1619,12 +1619,24 @@ int scsi_add_device(struct Scsi_Host *host, uint channel, } EXPORT_SYMBOL(scsi_add_device); -void scsi_rescan_device(struct scsi_device *sdev) +int scsi_rescan_device(struct scsi_device *sdev) { struct device *dev = &sdev->sdev_gendev; + int ret = 0; device_lock(dev); + /* + * Bail out if the device is not running. Otherwise, the rescan may + * block waiting for commands to be executed, with us holding the + * device lock. This can result in a potential deadlock in the power + * management core code when system resume is on-going. + */ + if (sdev->sdev_state != SDEV_RUNNING) { + ret = -EWOULDBLOCK; + goto unlock; + } + scsi_attach_vpd(sdev); scsi_cdl_check(sdev); @@ -1638,7 +1650,11 @@ void scsi_rescan_device(struct scsi_device *sdev) drv->rescan(dev); module_put(dev->driver->owner); } + +unlock: device_unlock(dev); + + return ret; } EXPORT_SYMBOL(scsi_rescan_device); diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 49f768d0ff37..4c2dc8150c6d 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -764,7 +764,7 @@ scsi_template_proc_dir(const struct scsi_host_template *sht); #define scsi_template_proc_dir(sht) NULL #endif extern void scsi_scan_host(struct Scsi_Host *); -extern void scsi_rescan_device(struct scsi_device *); +extern int scsi_rescan_device(struct scsi_device *sdev); extern void scsi_remove_host(struct Scsi_Host *); extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *); extern int scsi_host_busy(struct Scsi_Host *shost);