Re: WARNING from tty driver in 3.9-rc0

[Jiri Slaby]

On 02/26/2013 10:56 PM, Daniel Mack wrote:
> On Tue, Feb 26, 2013 at 10:25 PM, Larry Finger
> <Larry.Finger@xxxxxxxxxxxx> wrote:
>> Hi,
>>
>> With v3.8-8693-gbf722a0 from the mainline repo, I get the following warning
>> because the pointer for tty is NULL:
>>
>> [   34.956862] WARNING: at drivers/tty/tty_buffer.c:428
>> flush_to_ldisc+0x1bb/0x1c0()
>> [   34.956865] Hardware name: HP Pavilion dv2700 Notebook PC
>> [   34.956867] tty is NULL
>> [   34.956869] Modules linked in: arc4 b43 mac80211 cfg80211
>> snd_hda_codec_conexant snd_hda_intel rfkill snd_hda_codec ipv6 snd_pcm
>> kvm_amd snd_seq kvm bcma rng_core snd_timer snd_seq_device ssb mmc_core snd
>> pcmcia sr_mod cdrom sg soundcore forcedeth pcmcia_core snd_page_alloc
>> i2c_nforce2 i2c_core k8temp hwmon ehci_pci battery ac serio_raw joydev video
>> wmi button autofs4 ext4 mbcache jbd2 crc16 ohci_hcd ehci_hcd usbcore
>> usb_common thermal processor scsi_dh_alua scsi_dh_hp_sw scsi_dh_rdac
>> scsi_dh_emc scsi_dh ata_generic pata_acpi pata_amd
>> [   34.956936] Pid: 270, comm: kworker/1:1 Not tainted 3.8.0+ #92
>> [   34.956939] Call Trace:
>> [   34.956944]  [<ffffffff812acc00>] ? flush_to_ldisc+0x120/0x1c0
>> [   34.956951]  [<ffffffff81040a4a>] warn_slowpath_common+0x7a/0xc0
>> [   34.956955]  [<ffffffff81040b31>] warn_slowpath_fmt+0x41/0x50
>> [   34.956959]  [<ffffffff812acc9b>] flush_to_ldisc+0x1bb/0x1c0
>> [   34.956964]  [<ffffffff810640f1>] process_one_work+0x1f1/0x660
>> [   34.956968]  [<ffffffff81064085>] ? process_one_work+0x185/0x660
>> [   34.956972]  [<ffffffff81064900>] worker_thread+0x110/0x380
>> [   34.956978]  [<ffffffff810a5b7d>] ? trace_hardirqs_on+0xd/0x10
>> [   34.956982]  [<ffffffff810647f0>] ? rescuer_thread+0x250/0x250
>> [   34.956987]  [<ffffffff81069e96>] kthread+0xd6/0xe0
>> [   34.956992]  [<ffffffff81424c9b>] ? _raw_spin_unlock_irq+0x2b/0x50
>> [   34.956997]  [<ffffffff81069dc0>] ? __init_kthread_worker+0x70/0x70
>> [   34.957002]  [<ffffffff81425a7c>] ret_from_fork+0x7c/0xb0
>> [   34.957006]  [<ffffffff81069dc0>] ? __init_kthread_worker+0x70/0x70
>> [   34.957009] ---[ end trace f467d4f2302660c1 ]---
>> [   35.585060] forcedeth 0000:00:0a.0: irq 42 for MSI/MSI-X
>> [   35.585182] forcedeth 0000:00:0a.0 eth0: MSI enabled
>> [   36.140711] ------------[ cut here ]------------
>>
>>
>> I have not yet bisected this problem yet; however, I can if requested. Being
>> lazy, I hope that someone already has a patch, or can see the problem by
>> inspection. :)
> 
> FWIW, I see the same on an ARM embedded board ...

This one should be solved by Peter's "ldisc patchset". It didn't make it
to 3.9 though. Anyway, the warning was added for debugging purposes only
and it's apparently time to disable it now.

thanks,
-- 
js
suse labs
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