From: Sasha Levin <levinsasha928@gmail.com>
To: Jiri Slaby <jslaby@suse.cz>
Cc: Sasha Levin <sasha.levin@oracle.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Dave Jones <davej@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: tty ldisc lockups in linux-next
Date: Tue, 25 Sep 2012 11:47:01 +0200 [thread overview]
Message-ID: <50617D95.7010005@gmail.com> (raw)
In-Reply-To: <506171DA.9070102@suse.cz>
On 09/25/2012 10:56 AM, Jiri Slaby wrote:
> On 09/25/2012 10:55 AM, Sasha Levin wrote:
>> On 09/25/2012 10:52 AM, Jiri Slaby wrote:
>>>> Hi all,
>>>>>
>>>>> While fuzzing with trinity in a KVM tools guest running linux-next kernel, I keep hitting the following lockup:
>>> Hi, I'm confused here. Is this different to what you reported a couple
>>> days ago? Doesn't reverting aa3c8af86382 help in the end?
>>
>> I was just about to send a reply to that mail saying that while reverting aa3c8af86382 reduces the odds for seeing it, it still
>> happens. You were faster than me :)
>>
>> But yes, it still happens even if I revert aa3c8af86382 or try applying your patch in that thread.
>
> The patch won't help, it's kind of certain.
>
> Instead I still wonder what process sits on the terminal. Could you
> investigate?
>
It looks like sh is trying to read:
[ 606.950194] sh S 0000000000000001 4800 6260 1 0x00000000
[ 606.950194] ffff88000c0ddcc8 0000000000000082 ffffffff847baa68 0000000000000b02
[ 606.950194] ffff88000c0ddfd8 ffff88000c0ddfd8 ffff88000c0ddfd8 ffff88000c0ddfd8
[ 606.950194] ffff88000f578000 ffff88000c0bb000 ffff88000c0ddd98 ffff880040b4d000
[ 606.950194] Call Trace:
[ 606.950194] [<ffffffff83a0be45>] schedule+0x55/0x60
[ 606.950194] [<ffffffff83a09dd5>] schedule_timeout+0x45/0x360
[ 606.950194] [<ffffffff83a0d54d>] ? _raw_spin_unlock_irqrestore+0x5d/0xb0
[ 606.950194] [<ffffffff8117b13d>] ? trace_hardirqs_on+0xd/0x10
[ 606.950194] [<ffffffff83a0d574>] ? _raw_spin_unlock_irqrestore+0x84/0xb0
[ 606.950194] [<ffffffff81b98271>] n_tty_read+0x4c1/0x9a0
[ 606.950194] [<ffffffff83a0d54d>] ? _raw_spin_unlock_irqrestore+0x5d/0xb0
[ 606.950194] [<ffffffff8114d760>] ? try_to_wake_up+0x360/0x360
[ 606.950194] [<ffffffff81b922cf>] tty_read+0x8f/0x100
[ 606.950194] [<ffffffff8127187d>] vfs_read+0xad/0x180
[ 606.950194] [<ffffffff81271c10>] sys_read+0x50/0xa0
[ 606.950194] [<ffffffff83a0edcd>] system_call_fastpath+0x1a/0x1f
While init is trying to exit:
[ 605.524940] init D ffff88000d5b0000 3376 1 0 0x00000002
[ 605.527502] ffff88000d5adc28 0000000000000082 ffff88000d5adbe8 ffffffff81150ac5
[ 605.529685] ffff88000d5adfd8 ffff88000d5adfd8 ffff88000d5adfd8 ffff88000d5adfd8
[ 605.530939] ffff88000d613000 ffff88000d5b0000 ffff88000d5b08f0 7fffffffffffffff
[ 605.532064] Call Trace:
[ 605.532064] [<ffffffff81150ac5>] ? sched_clock_local+0x25/0xa0
[ 605.532064] [<ffffffff83a0be45>] schedule+0x55/0x60
[ 605.532064] [<ffffffff83a09dd5>] schedule_timeout+0x45/0x360
[ 605.532064] [<ffffffff83a0d54d>] ? _raw_spin_unlock_irqrestore+0x5d/0xb0
[ 605.532064] [<ffffffff8117b13d>] ? trace_hardirqs_on+0xd/0x10
[ 605.532064] [<ffffffff83a0d574>] ? _raw_spin_unlock_irqrestore+0x84/0xb0
[ 605.532064] [<ffffffff81137af7>] ? prepare_to_wait+0x77/0x90
[ 605.532064] [<ffffffff81b9b2c6>] tty_ldisc_wait_idle.isra.7+0x76/0xb0
[ 605.532064] [<ffffffff81137cd0>] ? abort_exclusive_wait+0xb0/0xb0
[ 605.532064] [<ffffffff81b9c03b>] tty_ldisc_hangup+0x1cb/0x320
[ 605.532064] [<ffffffff81b933a2>] ? __tty_hangup+0x122/0x430
[ 605.532064] [<ffffffff81b933aa>] __tty_hangup+0x12a/0x430
[ 605.532064] [<ffffffff83a0d574>] ? _raw_spin_unlock_irqrestore+0x84/0xb0
[ 605.532064] [<ffffffff81b955cc>] disassociate_ctty+0x6c/0x230
[ 605.532064] [<ffffffff8110e7e8>] do_exit+0x3d8/0xa90
[ 605.532064] [<ffffffff83a0e4d9>] ? retint_swapgs+0x13/0x1b
[ 605.532064] [<ffffffff8110ef64>] do_group_exit+0x84/0xd0
[ 605.532064] [<ffffffff8110efc2>] sys_exit_group+0x12/0x20
[ 605.532064] [<ffffffff83a0edcd>] system_call_fastpath+0x1a/0x1f
And the corresponding lock info:
[ 606.950194] Showing all locks held in the system:
[ 606.950194] 1 lock held by init/1:
[ 606.950194] #0: (&tty->ldisc_mutex){+.+.+.}, at: [<ffffffff81b9bf92>] tty_ldisc_hangup+0x122/0x320
[ 606.950194] 1 lock held by sh/6260:
[ 606.950194] #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff81b98078>] n_tty_read+0x2c8/0x9a0
prev parent reply other threads:[~2012-09-25 9:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-25 8:49 tty ldisc lockups in linux-next Sasha Levin
2012-09-25 8:52 ` Jiri Slaby
2012-09-25 8:55 ` Sasha Levin
2012-09-25 8:56 ` Jiri Slaby
2012-09-25 9:47 ` Sasha Levin [this message]
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