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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 46B8BC433EF for ; Tue, 5 Oct 2021 13:35:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E2BD613AC for ; Tue, 5 Oct 2021 13:35:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235002AbhJENhd (ORCPT ); Tue, 5 Oct 2021 09:37:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:53932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234170AbhJENhc (ORCPT ); Tue, 5 Oct 2021 09:37:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C7A3461373; Tue, 5 Oct 2021 13:35:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633440942; bh=rmiNW24/FYEIfXM5I6t4acvrWgnU8hlztAf4CfxGHdw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QvX/svW3718K8DxSSqNursVFPuWYzbbpBOhvWl1fm03YrqXamEV9oI6/3q7lSf7WJ lfmljhkzMWRNND5DXr3JVdPWMW0Nf+P35ScDeGdXvJTpj5/J3LMtedczUqSknj1nja fFAEKrWiFFM8PrjQWvapq8cKe0Uidg0ouI8W+xp4= Date: Tue, 5 Oct 2021 15:35:40 +0200 From: Greg Kroah-Hartman To: Ming Lei Cc: "Martin K . Petersen" , linux-scsi@vger.kernel.org, Changhui Zhong , Yi Zhang Subject: Re: [PATCH V3] scsi: core: put LLD module refcnt after SCSI device is released Message-ID: References: <20210930124415.1160754-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210930124415.1160754-1-ming.lei@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Thu, Sep 30, 2021 at 08:44:15PM +0800, Ming Lei wrote: > SCSI host release is triggered when SCSI device is freed, and we have to > make sure that LLD module won't be unloaded before SCSI host instance is > released because shost->hostt is required in host release handler. > > So make sure to put LLD module refcnt after SCSI device is released. What is a "LLD"? > Fix one kernel panic of 'BUG: unable to handle page fault for address' > reported by Changhui and Yi. > > Reported-by: Changhui Zhong > Reported-by: Yi Zhang > Cc: Greg Kroah-Hartman > Signed-off-by: Ming Lei > --- > drivers/scsi/scsi.c | 4 +++- > drivers/scsi/scsi_sysfs.c | 12 ++++++++++++ > include/scsi/scsi_device.h | 1 + > 3 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > index b241f9e3885c..291ecc33b1fe 100644 > --- a/drivers/scsi/scsi.c > +++ b/drivers/scsi/scsi.c > @@ -553,8 +553,10 @@ EXPORT_SYMBOL(scsi_device_get); > */ > void scsi_device_put(struct scsi_device *sdev) > { > - module_put(sdev->host->hostt->module); > + struct module *mod = sdev->host->hostt->module; > + > put_device(&sdev->sdev_gendev); > + module_put(mod); > } > EXPORT_SYMBOL(scsi_device_put); > > diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c > index 86793259e541..9ada26814011 100644 > --- a/drivers/scsi/scsi_sysfs.c > +++ b/drivers/scsi/scsi_sysfs.c > @@ -449,9 +449,16 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) > struct scsi_vpd *vpd_pg80 = NULL, *vpd_pg83 = NULL; > struct scsi_vpd *vpd_pg0 = NULL, *vpd_pg89 = NULL; > unsigned long flags; > + struct module *mod; > + bool put_mod = false; > > sdev = container_of(work, struct scsi_device, ew.work); > > + if (sdev->put_lld_mod_ref) { Why do you need this flag at all? Shouldn't you just always grab/release the module? Why would you not want to? thanks, greg k-h