Tested-by: Justin Ernst <justin.er...@hpe.com>

Passed the testing. Thanks Corey!
-Justin

> -----Original Message-----
> From: Corey Minyard [mailto:tcminy...@gmail.com] On Behalf Of
> miny...@acm.org
> Sent: Wednesday, August 22, 2018 12:20 PM
> To: Ernst, Justin <justin.er...@hpe.com>
> Cc: Corey Minyard <cminy...@mvista.com>; Banman, Andrew
> <aban...@hpe.com>; Anderson, Russ <russ.ander...@hpe.com>;
> openipmi-developer@lists.sourceforge.net; linux-ker...@vger.kernel.org
> Subject: [PATCH] ipmi: Rework SMI registration failure
> 
> From: Corey Minyard <cminy...@mvista.com>
> 
> There were certain situations where ipmi_register_smi() would return a
> failure, but the interface would still be registered and would need to be
> unregistered.  This is obviously a bad design and resulted in an oops in 
> certain
> failure cases.
> 
> If the interface is started up in ipmi_register_smi(), then an error occurs, 
> shut
> down the interface there so the cleanup can be done properly.
> 
> Fix the various smi users, too.
> 
> Signed-off-by: Corey Minyard <cminy...@mvista.com>
> Reported-by: Justin Ernst <justin.er...@hpe.com>
> Cc: Andrew Banman <aban...@hpe.com>
> Cc: Russ Anderson <russ.ander...@hpe.com>
> Cc: openipmi-developer@lists.sourceforge.net
> Cc: linux-ker...@vger.kernel.org
> ---
>  drivers/char/ipmi/ipmi_msghandler.c | 53 +++++++++++++++++++++--------
> --------
>  drivers/char/ipmi/ipmi_si_intf.c    | 17 +++---------
>  drivers/char/ipmi/ipmi_ssif.c       | 13 +++------
>  3 files changed, 37 insertions(+), 46 deletions(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c
> b/drivers/char/ipmi/ipmi_msghandler.c
> index 46ab1ba..04f64c5 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -3378,39 +3378,45 @@ int ipmi_register_smi(const struct
> ipmi_smi_handlers *handlers,
> 
>       rv = handlers->start_processing(send_info, intf);
>       if (rv)
> -             goto out;
> +             goto out_err;
> 
>       rv = __bmc_get_device_id(intf, NULL, &id, NULL, NULL, i);
>       if (rv) {
>               dev_err(si_dev, "Unable to get the device id: %d\n", rv);
> -             goto out;
> +             goto out_err_started;
>       }
> 
>       mutex_lock(&intf->bmc_reg_mutex);
>       rv = __scan_channels(intf, &id);
>       mutex_unlock(&intf->bmc_reg_mutex);
> +     if (rv)
> +             goto out_err_bmc_reg;
> 
> - out:
> -     if (rv) {
> -             ipmi_bmc_unregister(intf);
> -             list_del_rcu(&intf->link);
> -             mutex_unlock(&ipmi_interfaces_mutex);
> -             synchronize_srcu(&ipmi_interfaces_srcu);
> -             cleanup_srcu_struct(&intf->users_srcu);
> -             kref_put(&intf->refcount, intf_free);
> -     } else {
> -             /*
> -              * Keep memory order straight for RCU readers.  Make
> -              * sure everything else is committed to memory before
> -              * setting intf_num to mark the interface valid.
> -              */
> -             smp_wmb();
> -             intf->intf_num = i;
> -             mutex_unlock(&ipmi_interfaces_mutex);
> +     /*
> +      * Keep memory order straight for RCU readers.  Make
> +      * sure everything else is committed to memory before
> +      * setting intf_num to mark the interface valid.
> +      */
> +     smp_wmb();
> +     intf->intf_num = i;
> +     mutex_unlock(&ipmi_interfaces_mutex);
> 
> -             /* After this point the interface is legal to use. */
> -             call_smi_watchers(i, intf->si_dev);
> -     }
> +     /* After this point the interface is legal to use. */
> +     call_smi_watchers(i, intf->si_dev);
> +
> +     return 0;
> +
> + out_err_bmc_reg:
> +     ipmi_bmc_unregister(intf);
> + out_err_started:
> +     if (intf->handlers->shutdown)
> +             intf->handlers->shutdown(intf->send_info);
> + out_err:
> +     list_del_rcu(&intf->link);
> +     mutex_unlock(&ipmi_interfaces_mutex);
> +     synchronize_srcu(&ipmi_interfaces_srcu);
> +     cleanup_srcu_struct(&intf->users_srcu);
> +     kref_put(&intf->refcount, intf_free);
> 
>       return rv;
>  }
> @@ -3501,7 +3507,8 @@ void ipmi_unregister_smi(struct ipmi_smi *intf)
>       }
>       srcu_read_unlock(&intf->users_srcu, index);
> 
> -     intf->handlers->shutdown(intf->send_info);
> +     if (intf->handlers->shutdown)
> +             intf->handlers->shutdown(intf->send_info);
> 
>       cleanup_smi_msgs(intf);
> 
> diff --git a/drivers/char/ipmi/ipmi_si_intf.c 
> b/drivers/char/ipmi/ipmi_si_intf.c
> index 2194b4c..bb7d8af 100644
> --- a/drivers/char/ipmi/ipmi_si_intf.c
> +++ b/drivers/char/ipmi/ipmi_si_intf.c
> @@ -2102,18 +2102,9 @@ static int try_smi_init(struct smi_info *new_smi)
>                si_to_str[new_smi->io.si_type]);
> 
>       WARN_ON(new_smi->io.dev->init_name != NULL);
> -     kfree(init_name);
> -
> -     return 0;
> -
> -out_err:
> -     if (new_smi->intf) {
> -             ipmi_unregister_smi(new_smi->intf);
> -             new_smi->intf = NULL;
> -     }
> 
> + out_err:
>       kfree(init_name);
> -
>       return rv;
>  }
> 
> @@ -2246,6 +2237,8 @@ static void shutdown_smi(void *send_info)
> 
>       kfree(smi_info->si_sm);
>       smi_info->si_sm = NULL;
> +
> +     smi_info->intf = NULL;
>  }
> 
>  /*
> @@ -2259,10 +2252,8 @@ static void cleanup_one_si(struct smi_info
> *smi_info)
> 
>       list_del(&smi_info->link);
> 
> -     if (smi_info->intf) {
> +     if (smi_info->intf)
>               ipmi_unregister_smi(smi_info->intf);
> -             smi_info->intf = NULL;
> -     }
> 
>       if (smi_info->pdev) {
>               if (smi_info->pdev_registered)
> diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
> index fddf646..3574322 100644
> --- a/drivers/char/ipmi/ipmi_ssif.c
> +++ b/drivers/char/ipmi/ipmi_ssif.c
> @@ -1218,18 +1218,11 @@ static void shutdown_ssif(void *send_info)
>               complete(&ssif_info->wake_thread);
>               kthread_stop(ssif_info->thread);
>       }
> -
> -     /*
> -      * No message can be outstanding now, we have removed the
> -      * upper layer and it permitted us to do so.
> -      */
> -     kfree(ssif_info);
>  }
> 
>  static int ssif_remove(struct i2c_client *client)  {
>       struct ssif_info *ssif_info = i2c_get_clientdata(client);
> -     struct ipmi_smi *intf;
>       struct ssif_addr_info *addr_info;
> 
>       if (!ssif_info)
> @@ -1239,9 +1232,7 @@ static int ssif_remove(struct i2c_client *client)
>        * After this point, we won't deliver anything asychronously
>        * to the message handler.  We can unregister ourself.
>        */
> -     intf = ssif_info->intf;
> -     ssif_info->intf = NULL;
> -     ipmi_unregister_smi(intf);
> +     ipmi_unregister_smi(ssif_info->intf);
> 
>       list_for_each_entry(addr_info, &ssif_infos, link) {
>               if (addr_info->client == client) {
> @@ -1250,6 +1241,8 @@ static int ssif_remove(struct i2c_client *client)
>               }
>       }
> 
> +     kfree(ssif_info);
> +
>       return 0;
>  }
> 
> --
> 2.7.4


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