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Subject[PATCH 1/2] megaraid: fix BUG_ON() from incorrect use of delayed work
From c1d390d8e6128b050f0f66b1c33d390760deb3f4 Mon Sep 17 00:00:00 2001
From: Xiaotian Feng <xtfeng@gmail.com>
Date: Tue, 4 Dec 2012 19:33:54 +0800

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
---
drivers/scsi/megaraid/megaraid_sas.h | 2 +-
drivers/scsi/megaraid/megaraid_sas_base.c | 14 ++++++--------
2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 16b7a72..3b2365c 100644
--- 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
--- 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;
--
1.7.11.7


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