From patchwork Sat Sep 23 00:29:15 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: 725825 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 47276CE7A92 for ; Sat, 23 Sep 2023 00:29:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230481AbjIWA35 (ORCPT ); Fri, 22 Sep 2023 20:29:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230457AbjIWA3u (ORCPT ); Fri, 22 Sep 2023 20:29:50 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AC0B1B0; Fri, 22 Sep 2023 17:29:44 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1EFCC433C9; Sat, 23 Sep 2023 00:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695428983; bh=k/n1E/0sX1Kh1J/5A7PeVx3HzBPcsCroCRQBlVX2+y4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n2vLeUm9pAZl24FNr5syL9oQp/oVX1CWMGfGPVFcTTnusRkWYUbvIFUfD+a5/GVIh dB/f0RiilsjImr03os0zDxwGjO/7/IOn2qlnW1VPuf5eRPqsRDPOisvN4cHSCTuMmK 9DMt3MLCqbxFTwp2qF1812TBmJnD9bfOuQj0dhYxGbEiTkbfjES4N9JZQbJmJclxoX GjviXu2eZ7QhPYet6Z2oxoCrTmVooAUVmvYc997dlb+9q+Cl8JOD6g6JSfip8n3yLB l97i8eaaX29iUy8Bf3oky/amnrugSoH+o7XXFZLFTtMUg0Zz9dxOCryotJLTug2lRM uakbYrhWmwH4g== 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 v6 06/23] scsi: Do not attempt to rescan suspended devices Date: Sat, 23 Sep 2023 09:29:15 +0900 Message-ID: <20230923002932.1082348-7-dlemoal@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230923002932.1082348-1-dlemoal@kernel.org> References: <20230923002932.1082348-1-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 Reviewed-by: Bart Van Assche --- 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);