From: James Bottomley Date: Thu, 27 Jan 2011 21:12:37 +0000 (-0500) Subject: [SCSI] qla2xxx: Fix race that could hang kthread_stop() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=563585ec4bf1319f193c2f51682985bcae400cb4;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git [SCSI] qla2xxx: Fix race that could hang kthread_stop() 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. Fix by making sure we only set TASK_INTERRUPTIBLE before checking kthread_stop(). Reported-by: Bandan Das Acked-by: Madhuranath Iyengar Signed-off-by: James Bottomley --- diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c index c194c23ca1fb..15ce69eaaf4d 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));