Messages in this thread | | | Date | Thu, 27 Aug 2015 11:28:05 -0700 | Subject | Re: [PATCH] scsi: fix scsi_error_handler vs. scsi_host_dev_release race | From | Dan Williams <> |
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On Thu, Aug 27, 2015 at 11:16 AM, <mhocko@kernel.org> wrote: > From: Michal Hocko <mhocko@suse.com> > > b9d5c6b7ef57 ("[SCSI] cleanup setting task state in > scsi_error_handler()") has introduced a race between scsi_error_handler > and scsi_host_dev_release resulting in the hang when the device goes > away because scsi_error_handler might miss a wake up: > > CPU0 CPU1 > scsi_error_handler scsi_host_dev_release > kthread_stop() > kthread_should_stop() > test_bit(KTHREAD_SHOULD_STOP) > set_bit(KTHREAD_SHOULD_STOP) > wake_up_process() > wait_for_completion() > > set_current_state(TASK_INTERRUPTIBLE) > schedule() > > The most straightforward solution seems to be to invert the ordering of > the set_current_state and kthread_should_stop. > > The issue has been noticed during reboot test on a 3.0 based kernel but > the current code seems to be affected in the same way. > > Cc: stable # 3.6+ > Reported-and-Debugged-by: Mike Mayer <Mike.Meyer@teradata.com> > Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
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