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authorJason Yan <yanaijie@huawei.com>2018-09-25 04:56:54 +0200
committerMartin K. Petersen <martin.petersen@oracle.com>2018-09-26 03:20:23 +0200
commitb90cd6f2b905905fb42671009dc0e27c310a16ae (patch)
tree981dfa49113f511ed877ae497b0cba6bf716f89d /drivers/scsi/libsas
parentscsi: libsas: check the ata device status by ata_dev_enabled() (diff)
downloadlinux-b90cd6f2b905905fb42671009dc0e27c310a16ae.tar.xz
linux-b90cd6f2b905905fb42671009dc0e27c310a16ae.zip
scsi: libsas: fix a race condition when smp task timeout
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> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/libsas')
-rw-r--r--drivers/scsi/libsas/sas_expander.c9
1 files 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);
}