Re: [PATCH] fc: ensure scan_work isn't active when freeing fc_rport

[Hannes Reinecke <hare@suse.de>]

On 05/30/2014 04:59 PM, Neil Horman wrote:
> debugfs caught this:
> WARNING: at lib/debugobjects.c:260 debug_print_object+0x83/0xa0()
> ODEBUG: free active (active state 0) object type: work_struct
> hint: fc_scsi_scan_rport+0x0/0xd0 [scsi_transport_fc]
>   CPU: 1 PID: 184 Comm: kworker/1:1 Tainted: G        W
> --------------   3.10.0-123.el7.x86_64.debug #1
> Hardware name: HP ProLiant DL120 G7, BIOS J01 07/01/2013
> Workqueue: fc_wq_5 fc_rport_final_delete [scsi_transport_fc]
> Call Trace:
> [<ffffffff8169efec>] dump_stack+0x19/0x1b
> [<ffffffff8106cbd1>] warn_slowpath_common+0x61/0x80
> [<ffffffff8106cc4c>] warn_slowpath_fmt+0x5c/0x80
> [<ffffffff8133e003>] debug_print_object+0x83/0xa0
> [<ffffffffa04e2f40>] ? fc_parse_wwn+0x100/0x100
>
> [<ffffffff8133f23b>] debug_check_no_obj_freed+0x22b/0x270
> [<ffffffffa04e127e>] ? fc_rport_dev_release+0x1e/0x30
> [<ffffffff811db3e9>] kfree+0xd9/0x2d0
> [<ffffffffa04e127e>] fc_rport_dev_release+0x1e/0x30
> [<ffffffff81428032>] device_release+0x32/0xa0
> [<ffffffff8132701e>] kobject_release+0x7e/0x1b0
> [<ffffffff81326ed8>] kobject_put+0x28/0x60
> [<ffffffff81428397>] put_device+0x17/0x20
> [<ffffffffa04e5025>] fc_rport_final_delete+0x165/0x210
> [<ffffffff810959b0>] process_one_work+0x220/0x710
> [<ffffffff81095944>] ? process_one_work+0x1b4/0x710
> [<ffffffff81095fbb>] worker_thread+0x11b/0x3a0
> [<ffffffff81095ea0>] ? process_one_work+0x710/0x710
> [<ffffffff8109e0cd>] kthread+0xed/0x100
> [<ffffffff8109dfe0>] ? insert_kthread_work+0x80/0x80
> [<ffffffff816b2fec>] ret_from_fork+0x7c/0xb0
> [<ffffffff8109dfe0>] ? insert_kthread_work+0x80/0x80
>
> Seems to be because the scan_work work_struct might be active when the housing
> fc_rport struct gets freed.  Ensure that we cancel it prior to freeing the rport
>
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> CC: linux-scsi@vger.kernel.org
> CC: Robert Love <robert.w.love@intel.com>
> CC: Vasu Dev <vasu.dev@intel.com>
> ---
>   drivers/scsi/scsi_transport_fc.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
> index 4628fd5..5bd552c 100644
> --- a/drivers/scsi/scsi_transport_fc.c
> +++ b/drivers/scsi/scsi_transport_fc.c
> @@ -2548,6 +2548,7 @@ fc_rport_final_delete(struct work_struct *work)
>   			fc_flush_devloss(shost);
>   		if (!cancel_delayed_work(&rport->dev_loss_work))
>   			fc_flush_devloss(shost);
> +		cancel_work_sync(&rport->scan_work);
>   		spin_lock_irqsave(shost->host_lock, flags);
>   		rport->flags &= ~FC_RPORT_DEVLOSS_PENDING;
>   	}
>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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