megaraid: fix BUG_ON() from incorrect use of delayed work

megaraid use INIT_WORK to declare a hotplug_work, but cast the
hotplug_work from work_struct to delayed_work and
schedule_delayed_work on it.  This is very dangerous, as other part of
delayed_work might be kernel memories allocated by others.

With commit 8852aac ("workqueue: mod_delayed_work_on() shouldn't queue
timer on 0 delay"), schedule_delayed_work() will check dwork->timer
before queue_work even when @delay is 0, this causes megaraid code to
hit the BUG_ON() in workqueue code.  Change megaraid code to use
delayed work.

Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Neela Syam Kolli <megaraidlinux@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: linux-scsi@vger.kernel.org

diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 16b7a72..3b2365c 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -1276,7 +1276,7 @@ struct megasas_evt_detail {
 } __attribute__ ((packed));
 
 struct megasas_aen_event {
-       struct work_struct hotplug_work;
+       struct delayed_work hotplug_work;
        struct megasas_instance *instance;
 };
 

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index d2c5366..e4f2baa 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -2060,9 +2060,9 @@ megasas_service_aen(struct megasas_instance *instance, struct megasas_cmd *cmd)
                } else {
                        ev->instance = instance;
                        instance->ev = ev;
-                       INIT_WORK(&ev->hotplug_work, megasas_aen_polling);
-                       schedule_delayed_work(
-                               (struct delayed_work *)&ev->hotplug_work, 0);
+                       INIT_DELAYED_WORK(&ev->hotplug_work,
+                                         megasas_aen_polling);
+                       schedule_delayed_work(&ev->hotplug_work, 0);
                }
        }
 }
@@ -4352,8 +4352,7 @@ megasas_suspend(struct pci_dev *pdev, pm_message_t state)
        /* cancel the delayed work if this work still in queue */
        if (instance->ev != NULL) {
                struct megasas_aen_event *ev = instance->ev;
-               cancel_delayed_work_sync(
-                       (struct delayed_work *)&ev->hotplug_work);
+               cancel_delayed_work_sync(&ev->hotplug_work);
                instance->ev = NULL;
        }
 
@@ -4545,8 +4544,7 @@ static void __devexit megasas_detach_one(struct pci_dev *pdev)
        /* cancel the delayed work if this work still in queue*/
        if (instance->ev != NULL) {
                struct megasas_aen_event *ev = instance->ev;
-               cancel_delayed_work_sync(
-                       (struct delayed_work *)&ev->hotplug_work);
+               cancel_delayed_work_sync(&ev->hotplug_work);
                instance->ev = NULL;
        }
 
@@ -5190,7 +5188,7 @@ static void
 megasas_aen_polling(struct work_struct *work)
 {
        struct megasas_aen_event *ev =
-               container_of(work, struct megasas_aen_event, hotplug_work);
+               container_of(work, struct megasas_aen_event, hotplug_work.work);
        struct megasas_instance *instance = ev->instance;
        union megasas_evt_class_locale class_locale;
        struct  Scsi_Host *host;