On Thu, 2011-01-27 at 15:59 -0500, Bandan Das wrote:
> There is a small race window in qla2x00_do_dpc() between
> checking for kthread_should_stop() and going to sleep after
> setting TASK_INTERRUPTIBLE. If qla2x00_free_device() is called
> in this window, kthread_stop will wait forever because there
> will be no one to wake up the process.
>
>
> Signed-off-by: Bandan Das <bandan.das@xxxxxxxxxxx>
> Signed-off-by: Nate Dailey <nate.dailey@xxxxxxxxxxx>
> ---
> drivers/scsi/qla2xxx/qla_os.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
> index c194c23..8d14d77 100644
> --- a/drivers/scsi/qla2xxx/qla_os.c
> +++ b/drivers/scsi/qla2xxx/qla_os.c
> @@ -3286,6 +3286,8 @@ qla2x00_do_dpc(void *data)
> DEBUG3(printk("qla2x00: DPC handler sleeping\n"));
>
> set_current_state(TASK_INTERRUPTIBLE);
> + if (kthread_should_stop())
> + break;
> schedule();
> __set_current_state(TASK_RUNNING);
That's not really the accepted way to fix these race conditions because
of the double check of kthread_should_stop(); this is
James
---
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index c194c23..15ce69e 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -3282,10 +3282,10 @@ qla2x00_do_dpc(void *data)
set_user_nice(current, -20);
+ set_current_state(TASK_INTERRUPTIBLE);
while (!kthread_should_stop()) {
DEBUG3(printk("qla2x00: DPC handler sleeping\n"));
- set_current_state(TASK_INTERRUPTIBLE);
schedule();
__set_current_state(TASK_RUNNING);
@@ -3454,7 +3454,9 @@ qla2x00_do_dpc(void *data)
qla2x00_do_dpc_all_vps(base_vha);
ha->dpc_active = 0;
+ set_current_state(TASK_INTERRUPTIBLE);
} /* End of while(1) */
+ __set_current_state(TASK_RUNNING);
DEBUG(printk("scsi(%ld): DPC handler exiting\n", base_vha->host_no));
--
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