Re: [PATCH 21/21] TTY: move tty buffers to tty_port

From: Sasha Levin
Date: Wed Oct 31 2012 - 16:10:25 EST


On 10/31/2012 11:32 AM, Jiri Slaby wrote:
> On 10/31/2012 04:30 PM, Sasha Levin wrote:
>> On Wed, Oct 31, 2012 at 8:53 AM, Jiri Slaby <jslaby@xxxxxxx> wrote:
>>> On 10/25/2012 08:02 PM, Sasha Levin wrote:
>>>> Fuzzing with trinity inside a KVM tools (lkvm) guest with -next kernel
>>>> uncovered the following warning:
>>>
>>> I cannot reproduce that :(. Do you still see it?
>>
>> Yes, it reproduces pretty easily while fuzzing.
>
> What is your exact setup? I tried trinity with 100 000 syscalls inside
> KVM with an LDEP-enabled kernel. How many serial ports do you have in
> the guest? Any USB serials in there?

btw, I'm also seeing the following lockups, don't know if it's related:


[ 2283.070569] INFO: task trinity-child20:9161 blocked for more than 120 seconds.
[ 2283.071775] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 2283.074673] trinity-child20 D ffff8800276cb000 5424 9161 6364 0x00000000
[ 2283.076018] ffff880059d9da58 0000000000000002 0000000000000002 0000000000000000
[ 2283.077393] ffff880059d7b000 ffff880059d9dfd8 ffff880059d9dfd8 ffff880059d9dfd8
[ 2283.078763] ffff8800276cb000 ffff880059d7b000 ffff880059d9da78 ffff88001a095180
[ 2283.084144] Call Trace:
[ 2283.085039] [<ffffffff83a98bd5>] schedule+0x55/0x60
[ 2283.086748] [<ffffffff83a98bf3>] schedule_preempt_disabled+0x13/0x20
[ 2283.089000] [<ffffffff83a9735d>] __mutex_lock_common+0x36d/0x5a0
[ 2283.090658] [<ffffffff83a9afb3>] ? tty_lock_nested+0x73/0x80
[ 2283.091691] [<ffffffff83a9afb3>] ? tty_lock_nested+0x73/0x80
[ 2283.092779] [<ffffffff83a975cf>] mutex_lock_nested+0x3f/0x50
[ 2283.093875] [<ffffffff83a9afb3>] tty_lock_nested+0x73/0x80
[ 2283.094872] [<ffffffff83a9afcb>] tty_lock+0xb/0x10
[ 2283.095443] [<ffffffff81bae880>] tty_open+0x270/0x5f0
[ 2283.096181] [<ffffffff8127cda8>] chrdev_open+0xf8/0x1d0
[ 2283.097054] [<ffffffff8127693c>] do_dentry_open+0x1fc/0x310
[ 2283.098015] [<ffffffff8127ccb0>] ? cdev_put+0x20/0x20
[ 2283.098943] [<ffffffff8127777a>] finish_open+0x4a/0x60
[ 2283.099935] [<ffffffff81286947>] do_last+0xb87/0xe70
[ 2283.100910] [<ffffffff812844b0>] ? link_path_walk+0x70/0x900
[ 2283.101553] [<ffffffff81286cf2>] path_openat+0xc2/0x500
[ 2283.102282] [<ffffffff83a9a314>] ? _raw_spin_unlock_irqrestore+0x84/0xb0
[ 2283.103506] [<ffffffff8128716c>] do_filp_open+0x3c/0xa0
[ 2283.104282] [<ffffffff81296c11>] ? __alloc_fd+0x1e1/0x200
[ 2283.105278] [<ffffffff81277c0c>] do_sys_open+0x11c/0x1c0
[ 2283.106519] [<ffffffff81277ccc>] sys_open+0x1c/0x20
[ 2283.107241] [<ffffffff81277d01>] sys_creat+0x11/0x20
[ 2283.107975] [<ffffffff83a9be18>] tracesys+0xe1/0xe6
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