From: Jason Yan <yanaijie@huawei.com>
To: <martin.petersen@oracle.com>, <jejb@linux.vnet.ibm.com>
Cc: <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<john.garry@huawei.com>, <zhaohongjiang@huawei.com>,
<hare@suse.com>, <dan.j.williams@intel.com>, <jthumshirn@suse.de>,
<hch@lst.de>, <huangdaode@hisilicon.com>,
<chenxiang66@hisilicon.com>, <miaoxie@huawei.com>,
Jason Yan <yanaijie@huawei.com>, Ewan Milne <emilne@redhat.com>,
Tomas Henzl <thenzl@redhat.com>
Subject: [PATCH v3 5/5] scsi: libsas: fix a race condition when smp task timeout
Date: Tue, 25 Sep 2018 10:56:54 +0800 [thread overview]
Message-ID: <20180925025654.44053-6-yanaijie@huawei.com> (raw)
In-Reply-To: <20180925025654.44053-1-yanaijie@huawei.com>
When the lldd is processing the complete sas task in interrupt and set
the task stat as SAS_TASK_STATE_DONE, the smp timeout timer is able to
be triggered at the same time. And smp_task_timedout() will complete the
task wheter the SAS_TASK_STATE_DONE is set or not. Then the sas task may
freed before lldd end the interrupt process. Thus a use-after-free will
happen.
Fix this by calling the complete() only when SAS_TASK_STATE_DONE is not
set. And remove the check of the return value of the del_timer(). Once
the LLDD sets DONE, it must call task->done(), which will call
smp_task_done()->complete() and the task will be completed and freed
correctly.
Reported-by: chenxiang <chenxiang66@hisilicon.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
CC: John Garry <john.garry@huawei.com>
CC: Johannes Thumshirn <jthumshirn@suse.de>
CC: Ewan Milne <emilne@redhat.com>
CC: Christoph Hellwig <hch@lst.de>
CC: Tomas Henzl <thenzl@redhat.com>
CC: Dan Williams <dan.j.williams@intel.com>
CC: Hannes Reinecke <hare@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
---
drivers/scsi/libsas/sas_expander.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 52222940d398..0d1f72752ca2 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -48,17 +48,16 @@ static void smp_task_timedout(struct timer_list *t)
unsigned long flags;
spin_lock_irqsave(&task->task_state_lock, flags);
- if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
+ if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) {
task->task_state_flags |= SAS_TASK_STATE_ABORTED;
+ complete(&task->slow_task->completion);
+ }
spin_unlock_irqrestore(&task->task_state_lock, flags);
-
- complete(&task->slow_task->completion);
}
static void smp_task_done(struct sas_task *task)
{
- if (!del_timer(&task->slow_task->timer))
- return;
+ del_timer(&task->slow_task->timer);
complete(&task->slow_task->completion);
}
--
2.14.4
next prev parent reply other threads:[~2018-09-25 2:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 2:56 [PATCH v3 0/5] scsi: libsas: some code cleanups and bug fixes Jason Yan
2018-09-25 2:56 ` [PATCH v3 1/5] scsi: libsas: delete dead code in scsi_transport_sas.c Jason Yan
2018-09-25 2:56 ` [PATCH v3 2/5] scsi: libsas: make the lldd_port_deformed method optional Jason Yan
2018-09-25 2:56 ` [PATCH v3 3/5] scsi: libsas: always unregister the old device if going to discover new Jason Yan
2018-09-25 2:56 ` [PATCH v3 4/5] scsi: libsas: check the ata device status by ata_dev_enabled() Jason Yan
2018-09-25 2:56 ` Jason Yan [this message]
2018-09-26 1:20 ` [PATCH v3 0/5] scsi: libsas: some code cleanups and bug fixes Martin K. Petersen
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