Re: linux-next: Tree for Aug 7 [ call-trace on suspend: ext4 | pmrelated ? ]

[Colin Cross]

Can you try add a call to show_state_filter(TASK_UNINTERRUPTIBLE) in
the error path of try_to_freeze_tasks(), where it prints the "refusing
to freeze" message?  It will print the stack trace of every thread
since they are all in the freezer, so the output will be very long.

On Wed, Aug 7, 2013 at 4:02 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> On Wednesday, August 07, 2013 04:25:14 PM Sedat Dilek wrote:
>> On Wed, Aug 7, 2013 at 7:54 AM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>> > Hi all,
>> >
>> > Changes since 20130806:
>> >
>> > The ext4 tree lost its build failure.
>> >
>> > The mvebu tree gained a build failure so I used the version from
>> > next-20130806.
>> >
>> > The akpm tree gained conflicts against the ext4 tree.
>> >
>> > ----------------------------------------------------------------------------
>> >
>>
>> [ CC ext4 and pm folks ]
>>
>> I saw this on my 1st suspend which was not successful (2nd and 3rd try
>> I could suspend and resume):
>>
>> [ 5467.724074] PM: Syncing filesystems ... done.
>> [ 5467.973575] PM: Preparing system for mem sleep
>> [ 5467.974121] Freezing user space processes ...
>> [ 5487.970574] Freezing of tasks failed after 20.010 seconds (1 tasks
>> refusing to freeze, wq_busy=0):
>> [ 5487.970591] DOM Worker      D ffffffff81811820     0  2437      1 0x00000004
>> [ 5487.970595]  ffff880056ca3ca8 0000000000000002 00000000002d627f
>> 000009af00000002
>> [ 5487.970598]  ffff880066ede640 ffff880056ca3fd8 ffff880056ca3fd8
>> ffff880056ca3fd8
>> [ 5487.970601]  ffff880119f98340 ffff880066ede640 ffff880056ca3ca8
>> ffff88011fad5118
>> [ 5487.970604] Call Trace:
>> [ 5487.970612]  [<ffffffff81144360>] ? __lock_page+0x70/0x70
>> [ 5487.970615]  [<ffffffff816e8179>] schedule+0x29/0x70
>> [ 5487.970618]  [<ffffffff816e824f>] io_schedule+0x8f/0xd0
>> [ 5487.970621]  [<ffffffff8114436e>] sleep_on_page+0xe/0x20
>> [ 5487.970624]  [<ffffffff816e4be2>] __wait_on_bit+0x62/0x90
>> [ 5487.970627]  [<ffffffff81144f9b>] ? find_get_pages_tag+0xcb/0x170
>> [ 5487.970630]  [<ffffffff811444d0>] wait_on_page_bit+0x80/0x90
>> [ 5487.970633]  [<ffffffff8108a0e0>] ? wake_atomic_t_function+0x40/0x40
>> [ 5487.970636]  [<ffffffff811445ec>] filemap_fdatawait_range+0x10c/0x190
>> [ 5487.970640]  [<ffffffff81145ce0>] filemap_write_and_wait_range+0x50/0x80
>> [ 5487.970644]  [<ffffffff81246c3d>] ext4_sync_file+0x15d/0x340
>> [ 5487.970648]  [<ffffffff811db8dd>] do_fsync+0x5d/0x90
>> [ 5487.970651]  [<ffffffff811dbcc0>] SyS_fsync+0x10/0x20
>> [ 5487.970655]  [<ffffffff816f25ef>] tracesys+0xe1/0xe6
>> [ 5487.970658]
>> [ 5487.970659] Restarting tasks ... done.
>>
>> With yesterday's -next I did not have issues like this.
>
> It looks like ext4 was doing fsync, so it scheduled a write a waited for it
> to complete, but that never happened (most likely whoever was supposed to do
> the write had been already frozen then).
>
> Thanks,
> Rafael
>
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