On Fri, Aug 10, 2012 at 2:58 AM, Michael Christie <micha...@cs.wisc.edu> wrote:
>
> On Aug 8, 2012, at 4:42 AM, Fubo Chen <fubo.c...@gmail.com> wrote:
>
>> Anyone seen this before ? Also occurs with 3.4.1.
>>
>>
>> ======================================================
>> [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ]
>> 3.6.0-rc1-debug+ #1 Not tainted
>> ------------------------------------------------------
>> swapper/1/0 [HC0[0]:SC1[1]:HE0:SE0] is trying to acquire:
>> (&(&session->lock)->rlock){+.-...}, at: [<ffffffffa025dc08>]
>> iscsi_eh_cmd_timed_out+0x58/0x2e0 [libiscsi]
>>
>> and this task is already holding:
>> (&(&q->__queue_lock)->rlock){-.-...}, at: [<ffffffff811f6965>]
>> blk_rq_timed_out_timer+0x25/0x140
>> which would create a new lock dependency:
>> (&(&q->__queue_lock)->rlock){-.-...} -> (&(&session->lock)->rlock){+.-...}
>>
>> but this new dependency connects a HARDIRQ-irq-safe lock:
>> (&(&q->__queue_lock)->rlock){-.-...}
>> ... which became HARDIRQ-irq-safe at:
>> [<ffffffff8109b5ca>] __lock_acquire+0x7ea/0x1ba0
>> [<ffffffff8109cfc2>] lock_acquire+0x92/0x140
>> [<ffffffff814b41c5>] _raw_spin_lock_irqsave+0x65/0xb0
>> [<ffffffff812e2974>] blk_done+0x34/0x110
>> [<ffffffff81295889>] vring_interrupt+0x49/0xc0
>> [<ffffffff810c68f5>] handle_irq_event_percpu+0x75/0x270
>> [<ffffffff810c6b38>] handle_irq_event+0x48/0x70
>> [<ffffffff810c9477>] handle_edge_irq+0x77/0x110
>> [<ffffffff81004042>] handle_irq+0x22/0x40
>> [<ffffffff814bda2a>] do_IRQ+0x5a/0xe0
>> [<ffffffff814b436f>] ret_from_intr+0x0/0x1a
>> [<ffffffff8100a7da>] default_idle+0x4a/0x170
>> [<ffffffff8100b609>] cpu_idle+0xe9/0x130
>> [<ffffffff814a4c6e>] start_secondary+0x26a/0x26c
>
>
> Does this error only occur when using some sort of virt setup?
>
> I do not think we will hit this with iscsi, because we do not ever grab the
> queue lock for a iscsi device from hard irq context. It is always done from
> softirq or thread context. The snippet above seems to be from the
> virtio_blk.c code.
Yes. This happened inside KVM machine.
Fubo.
--
You received this message because you are subscribed to the Google Groups
"open-iscsi" group.
To post to this group, send email to open-iscsi@googlegroups.com.
To unsubscribe from this group, send email to
open-iscsi+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/open-iscsi?hl=en.
