From patchwork Tue Sep 26 08:14:50 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: 727032 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 0868CE7D24D for ; Tue, 26 Sep 2023 08:15:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233948AbjIZIPi (ORCPT ); Tue, 26 Sep 2023 04:15:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233929AbjIZIP3 (ORCPT ); Tue, 26 Sep 2023 04:15:29 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68EBE116; Tue, 26 Sep 2023 01:15:22 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E1DAC433C9; Tue, 26 Sep 2023 08:15:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695716122; bh=k/n1E/0sX1Kh1J/5A7PeVx3HzBPcsCroCRQBlVX2+y4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xuwgpr3n/fB+h8EdFfzEwH+uWC4caIaFa+P83BoiwdKp7UupqbE4a6I/bNPg0H6o4 xYL1+mAsW4ql0Kkaq+eO8Eon1iFgEzd5ZIiQB+L2ZtibSdWUp3+dp6KFQI33b/8yVS DV9u/OGZh6Q+w1XwPsFoGqta3XNcWtUOAkSyV4TMAfcpWvzLPZ0IBreUQMbin4aYTu V9Lfsm2UD1kp58Tu2mzN6bHvXgnw/kRtgmHZpDZPjqxdZbHlLvZisbQcU0ifQ0uhEG IvwuPLyf94PYYvIMrJzj93Q+1oVqFUVeciQ556a8xmcs+wYyPA1yg+/Q7HJkgOn6xM rE9KmOjSCDE0Q== 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 v7 06/23] scsi: Do not attempt to rescan suspended devices Date: Tue, 26 Sep 2023 17:14:50 +0900 Message-ID: <20230926081507.69346-7-dlemoal@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230926081507.69346-1-dlemoal@kernel.org> References: <20230926081507.69346-1-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 Tested-by: Geert Uytterhoeven Reviewed-by: Martin K. Petersen --- 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);