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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 0B5CFECE599 for ; Wed, 16 Oct 2019 19:26:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5DBA2053B for ; Wed, 16 Oct 2019 19:26:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406507AbfJPT0J (ORCPT ); Wed, 16 Oct 2019 15:26:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51018 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403999AbfJPT0J (ORCPT ); Wed, 16 Oct 2019 15:26:09 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 839E718C8932; Wed, 16 Oct 2019 19:26:00 +0000 (UTC) Received: from dhcp-17-182.bos.redhat.com (ovpn-116-165.phx2.redhat.com [10.3.116.165]) by smtp.corp.redhat.com (Postfix) with ESMTP id AF73D5C1D4; Wed, 16 Oct 2019 19:25:56 +0000 (UTC) Subject: Re: [PATCH] ipmi: Don't allow device module unload when in use To: minyard@acm.org Cc: openipmi-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org, Corey Minyard References: <20191014134141.GA25427@t560> <20191014154632.11103-1-minyard@acm.org> From: Tony Camuso Message-ID: Date: Wed, 16 Oct 2019 15:25:56 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <20191014154632.11103-1-minyard@acm.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.70]); Wed, 16 Oct 2019 19:26:08 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/14/19 11:46 AM, minyard@acm.org wrote: > From: Corey Minyard > > If something has the IPMI driver open, don't allow the device > module to be unloaded. Before it would unload and the user would > get errors on use. > > This change is made on user request, and it makes it consistent > with the I2C driver, which has the same behavior. > > It does change things a little bit with respect to kernel users. > If the ACPI or IPMI watchdog (or any other kernel user) has > created a user, then the device module cannot be unloaded. Before > it could be unloaded, > > This does not affect hot-plug. If the device goes away (it's on > something removable that is removed or is hot-removed via sysfs) > then it still behaves as it did before. > > Reported-by: tony camuso > Signed-off-by: Corey Minyard > --- > Tony, here is a suggested change for this. Can you look it over and > see if it looks ok? > > Thanks, > > -corey > > drivers/char/ipmi/ipmi_msghandler.c | 23 ++++++++++++++++------- > include/linux/ipmi_smi.h | 12 ++++++++---- > 2 files changed, 24 insertions(+), 11 deletions(-) Hi Corey. You changed ipmi_register_ipmi to ipmi_add_ipmi in ipmi_msghandler, but you did not change it where it is actually called. # grep ipmi_register_smi drivers/char/ipmi/*.c drivers/char/ipmi/ipmi_powernv.c: rc = ipmi_register_smi(&ipmi_powernv_smi_handlers, ipmi, dev, 0); drivers/char/ipmi/ipmi_si_intf.c: rv = ipmi_register_smi(&handlers, drivers/char/ipmi/ipmi_ssif.c: rv = ipmi_register_smi(&ssif_info->handlers, Is there a reason for changing the interface name? Is this something that I could do instead of troubling you with it? Regards, Tony > > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c > index 2aab80e19ae0..15680de18625 100644 > --- a/drivers/char/ipmi/ipmi_msghandler.c > +++ b/drivers/char/ipmi/ipmi_msghandler.c > @@ -448,6 +448,8 @@ enum ipmi_stat_indexes { > > #define IPMI_IPMB_NUM_SEQ 64 > struct ipmi_smi { > + struct module *owner; > + > /* What interface number are we? */ > int intf_num; > > @@ -1220,6 +1222,11 @@ int ipmi_create_user(unsigned int if_num, > if (rv) > goto out_kfree; > > + if (!try_module_get(intf->owner)) { > + rv = -ENODEV; > + goto out_kfree; > + } > + > /* Note that each existing user holds a refcount to the interface. */ > kref_get(&intf->refcount); > > @@ -1349,6 +1356,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user) > } > > kref_put(&intf->refcount, intf_free); > + module_put(intf->owner); > } > > int ipmi_destroy_user(struct ipmi_user *user) > @@ -2459,7 +2467,7 @@ static int __get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc) > * been recently fetched, this will just use the cached data. Otherwise > * it will run a new fetch. > * > - * Except for the first time this is called (in ipmi_register_smi()), > + * Except for the first time this is called (in ipmi_add_smi()), > * this will always return good data; > */ > static int __bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc, > @@ -3377,10 +3385,11 @@ static void redo_bmc_reg(struct work_struct *work) > kref_put(&intf->refcount, intf_free); > } > > -int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > - void *send_info, > - struct device *si_dev, > - unsigned char slave_addr) > +int ipmi_add_smi(struct module *owner, > + const struct ipmi_smi_handlers *handlers, > + void *send_info, > + struct device *si_dev, > + unsigned char slave_addr) > { > int i, j; > int rv; > @@ -3406,7 +3415,7 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > return rv; > } > > - > + intf->owner = owner; > intf->bmc = &intf->tmp_bmc; > INIT_LIST_HEAD(&intf->bmc->intfs); > mutex_init(&intf->bmc->dyn_mutex); > @@ -3514,7 +3523,7 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > > return rv; > } > -EXPORT_SYMBOL(ipmi_register_smi); > +EXPORT_SYMBOL(ipmi_add_smi); > > static void deliver_smi_err_response(struct ipmi_smi *intf, > struct ipmi_smi_msg *msg, > diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h > index 4dc66157d872..deec18b8944a 100644 > --- a/include/linux/ipmi_smi.h > +++ b/include/linux/ipmi_smi.h > @@ -224,10 +224,14 @@ static inline int ipmi_demangle_device_id(uint8_t netfn, uint8_t cmd, > * is called, and the lower layer must get the interface from that > * call. > */ > -int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > - void *send_info, > - struct device *dev, > - unsigned char slave_addr); > +int ipmi_add_smi(struct module *owner, > + const struct ipmi_smi_handlers *handlers, > + void *send_info, > + struct device *dev, > + unsigned char slave_addr); > + > +#define ipmi_register_smi(handlers, send_info, dev, slave_addr) \ > + ipmi_add_smi(THIS_MODULE, handlers, send_info, dev, slave_addr) > > /* > * Remove a low-level interface from the IPMI driver. This will >