On Mon, Jan 21, 2013 at 11:47 AM, Jan Kara [off-list ref] wrote:

On Sun 20-01-13 01:06:40, Sedat Dilek wrote:

quoted

On Sun, Jan 20, 2013 at 12:44 AM, Sedat Dilek [off-list ref] wrote:

quoted

Hi,

I and some others hit a similiar problem in Linux-Next
(next-20130118), please see [1] and [2].

[3] has a interim analyze of my problems.

After suspecting the problem was caused by TTY-NEXT, it turned out to
be a JBD2 problem finally.
The freezer/pm_test was helpful to hit the issue (Thanks Rafael for the hint!).

So, the issue has two faces: TTY and JBD2.
[4] gives a list and URLs of the patches I had to apply to have a
clean system again.

After applying the two TTY patches (without Eric's JBD2-fix!) the
call-trace after freezer/pm_test looked like this;

[  433.527986] PM: Syncing filesystems ... done.
[  433.843761] PM: Preparing system for mem sleep
[  436.306002] Freezing user space processes ...
[  456.304956] Freezing of tasks failed after 20.01 seconds (1 tasks
refusing to freeze, wq_busy=0):
[  456.305060] Cache I/O       D ffffffff8180d780     0  2132      1 0x00000004
[  456.305065]  ffff88007b9dfe18 0000000000000046 ffff88007b9dfdc8
0000000300000001
[  456.305069]  ffff880097e21720 ffff88007b9dffd8 ffff88007b9dffd8
ffff88007b9dffd8
[  456.305072]  ffff880119b32e40 ffff880097e21720 ffff88007b9dfe28
ffff880118077800
[  456.305076] Call Trace:
[  456.305085]  [<ffffffff816b7469>] schedule+0x29/0x70
[  456.305089]  [<ffffffff8129067d>] jbd2_log_wait_commit+0xcd/0x1a0
[  456.305094]  [<ffffffff8107eac0>] ? add_wait_queue+0x60/0x60
[  456.305098]  [<ffffffff812307a5>] ext4_sync_file+0x205/0x380
[  456.305103]  [<ffffffff811c43ad>] do_fsync+0x5d/0x90
[  456.305108]  [<ffffffff8119442b>] ? sys_write+0x6b/0xa0
[  456.305111]  [<ffffffff811c4790>] sys_fsync+0x10/0x20
[  456.305114]  [<ffffffff816c0edd>] system_call_fastpath+0x1a/0x1f
[  456.305122]
[  456.305124] Restarting tasks ... done.
[  456.315056] video LNXVIDEO:00: Restoring backlight state

After applying Eric's patch [5], I could not hit the call-trace again.
NOTE: The patch is from December 2012 and is not shipped in latest Linux-Next.

The attached testcase script was helpful to force the call-trace.
I have run 50 loops of it w/o an issue!

Feel free to add a Reported-by/Tested-by.
( The issue kept me busy for the last days. )

Regards,
- Sedat -

[1] http://marc.info/?t=135283664600002&r=1&w=2
[2] http://marc.info/?t=135862023700004&r=1&w=2
[3] http://marc.info/?l=linux-kernel&m=135862010419101&w=2
[4] http://marc.info/?l=linux-next&m=135863550923093&w=2
[5] http://patchwork.ozlabs.org/patch/207237/

Hi all,

this is really ugly... I could cry!

GRRR, I have hit the original issue again while running my testcase script!

[  363.831226] PM: Syncing filesystems ... done.
[  363.988855] PM: Preparing system for mem sleep
[  369.032965] Freezing user space processes ... (elapsed 0.11 seconds) done.
[  369.145792] Freezing remaining freezable tasks ...
[  389.137643] Freezing of tasks failed after 20.01 seconds (1 tasks
refusing to freeze, wq_busy=0):
[  389.137760] jbd2/loop0-8    D ffffffff8180d780     0   295      2 0x00000000
[  389.137769]  ffff8801181dfb68 0000000000000046 ffff880117de5c80
0000000000000001
[  389.137778]  ffff880117de5c80 ffff8801181dffd8 ffff8801181dffd8
ffff8801181dffd8
[  389.137784]  ffffffff81c15440 ffff880117de5c80 ffff8801181dfb68
ffff88011fa14738
[  389.137791] Call Trace:
[  389.137810]  [<ffffffff811c6830>] ? __wait_on_buffer+0x30/0x30
[  389.137819]  [<ffffffff816b7479>] schedule+0x29/0x70
[  389.137825]  [<ffffffff816b754f>] io_schedule+0x8f/0xd0
[  389.137832]  [<ffffffff811c683e>] sleep_on_buffer+0xe/0x20
[  389.137842]  [<ffffffff816b5d4f>] __wait_on_bit+0x5f/0x90
[  389.137849]  [<ffffffff811c5ef1>] ? submit_bh+0x121/0x1e0
[  389.137856]  [<ffffffff811c6830>] ? __wait_on_buffer+0x30/0x30
[  389.137864]  [<ffffffff816b5dfc>] out_of_line_wait_on_bit+0x7c/0x90
[  389.137873]  [<ffffffff8107eb00>] ? autoremove_wake_function+0x40/0x40
[  389.137879]  [<ffffffff811c682e>] __wait_on_buffer+0x2e/0x30
[  389.137891]  [<ffffffff8128c02c>]
jbd2_journal_commit_transaction+0x18cc/0x1d60
[  389.137899]  [<ffffffff816b860e>] ? _raw_spin_lock_irqsave+0x2e/0x40
[  389.137908]  [<ffffffff81069fbf>] ? try_to_del_timer_sync+0x4f/0x70
[  389.137915]  [<ffffffff81290836>] kjournald2+0xd6/0x3e0
[  389.137921]  [<ffffffff8107eac0>] ? add_wait_queue+0x60/0x60
[  389.137926]  [<ffffffff81290760>] ? commit_timeout+0x10/0x10
[  389.137932]  [<ffffffff8107ded0>] kthread+0xc0/0xd0
[  389.137939]  [<ffffffff8107de10>] ? flush_kthread_worker+0xb0/0xb0
[  389.137946]  [<ffffffff816c0e2c>] ret_from_fork+0x7c/0xb0
[  389.137951]  [<ffffffff8107de10>] ? flush_kthread_worker+0xb0/0xb0
[  389.138017]
[  389.138021] Restarting kernel threads ... done.
[  389.138173] Restarting tasks ... done.
[  389.147980] video LNXVIDEO:00: Restoring backlight state

I suspect there are still issues in JBD2 (BTW I run here EXT4FS).

[  389.137643] Freezing of tasks failed after 20.01 seconds (1 tasks
refusing to freeze, wq_busy=0):
[  389.137760] jbd2/loop0-8    D ffffffff8180d780     0   295      2 0x00000000

Have a good night, /me -> watching TV!

  The traces don't suggest an ext4/jbd2 problem. What is happening is that
jbd2 is waiting for IO to finish and that never happens. Seeing that you
loop device I'd think it's some interaction of the loop device and
freezing. Can you reproduce the issue without the loop device (i.e. with
the filesystem directly on e.g. scsi disk)? I suspect the reason is
something like that the backing filesystem is already frozen so filesystem
on top of it cannot write all the data and hangs waiting for IO -> suspend
doesn't happen. Contents of /proc/mounts and losetup -l would help us
understand what's going on.

As said I am here in a very uncommon WUBI environment means my
Ubuntu/precise rootfs-image lays on the Win7-partition (NTFS).
Your explanation sounds reasonable to me as this line from my attached
testcase causes the troubles.

     echo mem > /sys/power/state && sleep 1

So, /sys/ is not writable immediately after freezer ends

I checked again and again my logs and have seen "starving" lines
reported by rtkit-daemon, but did not really get wiser what they want
to tell me. Stopping rtkit-daemon or resetting all or all-known
threads before running my pm_test/freezer did not help, too.

/usr/sbin/rtkitctl --help
rtkitctl [options]

  -h, --help         Show this help
      --version      Show version

      --reset-known  Reset real-time status of known threads
      --reset-all    Reset real-time status of all threads
      --start        Start RealtimeKit if it is not running already
  -k, --exit         Terminate running RealtimeKit daemon

Here are the outputs you wanted with some more (fstab, grub-config) etc.
I have here no -l option for losetup command.


- Sedat -

P.S.: Outputs for Honza...

$ sudo cat /proc/mounts
rootfs / rootfs rw 0 0
sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
udev /dev devtmpfs rw,relatime,size=1966948k,nr_inodes=491737,mode=755 0 0
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
tmpfs /run tmpfs rw,nosuid,relatime,size=788076k,mode=755 0 0
/dev/sda2 /host fuseblk
rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096
0 0
/dev/loop0 / ext4 rw,relatime,errors=remount-ro,data=ordered 0 0
none /sys/fs/fuse/connections fusectl rw,relatime 0 0
none /sys/kernel/debug debugfs rw,relatime 0 0
none /sys/kernel/security securityfs rw,relatime 0 0
none /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0
none /run/shm tmpfs rw,nosuid,nodev,relatime 0 0
gvfs-fuse-daemon /home/wearefam/.gvfs fuse.gvfs-fuse-daemon
rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0

$ sudo losetup --all --verbose
/dev/loop0: [0802]:17982 (/host/ubuntu/disks/root.disk)

$ sudo losetup --find --verbose
Loop device is /dev/loop1
/dev/loop1

 [ /etc/fstab ]
# /etc/fstab: static file system information.

# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).

# <file system>                 <mount point>   <type>  <options>
         <dump>  <pass>
proc                            /proc           proc
nodev,noexec,nosuid     0       0
/host/ubuntu/disks/root.disk    /               ext4
loop,errors=remount-ro  0       1
/host/ubuntu/disks/swap.disk    none            swap    loop,sw
         0       0
- EOF -

[ /boot/grub/grub.cfg ]
...
menuentry 'Ubuntu, mit Linux 3.8.0-rc4-next20130121-1-iniza-generic'
--class ubuntu --class gnu-linux --class gnu --class os {
        set gfxpayload=$linux_gfx_mode
        insmod part_msdos
        insmod ntfs
        set root='(hd0,msdos2)'
        search --no-floppy --fs-uuid --set=root 001AADA61AAD9964
        loopback loop0 /ubuntu/disks/root.disk
        set root=(loop0)
        linux   /boot/vmlinuz-3.8.0-rc4-next20130121-1-iniza-generic
root=UUID=001AADA61AAD9964 loop=/ubuntu/disks/root.disk ro
        initrd  /boot/initrd.img-3.8.0-rc4-next20130121-1-iniza-generic
}
...

Hope this helps you!

Regards,
- Sedat -

                                                                Honza
--
Jan Kara [off-list ref]
SUSE Labs, CR