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[SCSI] qla2xxx: Fix race that could hang kthread_stop()

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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 <bandan.das@stratus.com>
Acked-by: Madhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
This commit is contained in:
James Bottomley 2011-01-27 16:12:37 -05:00
parent 3c6c0d6ca3
commit 563585ec4b
1 changed files with 3 additions and 1 deletions
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4
drivers/scsi/qla2xxx/qla_os.c
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@ -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));