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Commit 563585ec authored by James Bottomley's avatar James Bottomley
Browse files

[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: default avatarBandan Das <bandan.das@stratus.com>
Acked-by: default avatarMadhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent 3c6c0d6c

drivers/scsi/qla2xxx/qla_os.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -3282,10 +3282,10 @@ qla2x00_do_dpc(void *data) 




	set_user_nice(current, -20);

	set_user_nice(current, -20);





	set_current_state(TASK_INTERRUPTIBLE);

	while (!kthread_should_stop()) {

	while (!kthread_should_stop()) {

		DEBUG3(printk("qla2x00: DPC handler sleeping\n"));

		DEBUG3(printk("qla2x00: DPC handler sleeping\n"));





		set_current_state(TASK_INTERRUPTIBLE);

		schedule();

		schedule();

		__set_current_state(TASK_RUNNING);

		__set_current_state(TASK_RUNNING);
@@ -3454,7 +3454,9 @@ qla2x00_do_dpc(void *data) 
		qla2x00_do_dpc_all_vps(base_vha);

		qla2x00_do_dpc_all_vps(base_vha);





		ha->dpc_active = 0;

		ha->dpc_active = 0;

		set_current_state(TASK_INTERRUPTIBLE);

	} /* End of while(1) */

	} /* End of while(1) */

	__set_current_state(TASK_RUNNING);





	DEBUG(printk("scsi(%ld): DPC handler exiting\n", base_vha->host_no));

	DEBUG(printk("scsi(%ld): DPC handler exiting\n", base_vha->host_no));