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 <[email protected]>
Signed-off-by: Jason Yan <[email protected]>
CC: John Garry <[email protected]>
CC: Johannes Thumshirn <[email protected]>
CC: Ewan Milne <[email protected]>
CC: Christoph Hellwig <[email protected]>
CC: Tomas Henzl <[email protected]>
CC: Dan Williams <[email protected]>
CC: Hannes Reinecke <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: John Garry <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

0 files changed, 0 insertions, 0 deletions