scsi: libsas: fix a race condition when smp task timeout
authorJason Yan <yanaijie@huawei.com>
Tue, 25 Sep 2018 02:56:54 +0000 (10:56 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 10 May 2019 15:54:04 +0000 (17:54 +0200)
commit0f18e433b97bf74bb62e0caa95c61e8631967fb9
tree68f7c59685994ad5cfa7efff7f966608b1b568d2
parente629cabe34ed1a262d0411b51467539f0ffd250a
scsi: libsas: fix a race condition when smp task timeout

commit b90cd6f2b905905fb42671009dc0e27c310a16ae upstream.

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>
Cc: Guenter Roeck <linux@roeck-us.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/scsi/libsas/sas_expander.c