Am 02.11.2015 um 09:57 schrieb Anton Ivanov:
> On 02/11/15 08:52, Richard Weinberger wrote:
>> Am 02.11.2015 um 09:41 schrieb Anton Ivanov:
>>> On 02/11/15 08:37, Richard Weinberger wrote:
>>>> Hi!
>>>>
>>>> Am 02.11.2015 um 09:14 schrieb Anton Ivanov:
>>>>> I was testing under similar conditions (CPU pinning using taskset -c 0 on
>>>>> a multicore).
>>>>>
>>>>> I have removed it and run some retests - I cannot reproduce the hang at
>>>>> this point with my config
>>>>>
>>>>> I am going to run a defconfig and compare the results to see if this will
>>>>> give me any insights on the root cause.
>>>> I can reproduce on both my build machine (8 core) and my laptop (4 core).
>>>> If it helps I can share the rootfs.
>>>>
>>>> On my laptop I was able to reproduce within 5 minutes.
>>>> 1. make defconfig ARCH=um
>>>> 2. make -j 4 linux ARCH=um
>>>> 3. ./linux ubda=../Downloads/Debian-Squeeze-AMD64-root_fs mem=1G
>>>> 4. login to tty0
>>>> 5. wait a few minutes
>>>> 6. try to run top, it will hang in nanosleep
>>> Pretty much the same. Does not hang, multiple test runs. Userspace is a
>>> relatively full install of a debian jessie.
>>>
>>> I ran deconfig and did a diff. The prime suspect differences between my
>>> config and defconfig are stack order 3 (not 1) and io sched of cfq, not
>>> deadline.
>>>
>>> I am going to retest just with these first to see if one of them is the
>>> culprit, if that does not make a difference, run it with defconfig and try
>>> to reproduce the hang.
>> I'm pretty sure that you don't see the issue as your Jessy userspace uses
>> nanosleep periodically.
>
> There are quite a few things running so this may indeed be the case.
>
> What do you use for userspace (so I can try to reproduce this and debug it)?
Debian Squeeze amd64 with almost nothing running.
PID TTY STAT TIME COMMAND
2 ? S 0:00 [kthreadd]
3 ? S 0:00 \_ [ksoftirqd/0]
4 ? S 0:00 \_ [kworker/0:0]
5 ? S< 0:00 \_ [kworker/0:0H]
6 ? S 0:00 \_ [kworker/u2:0]
7 ? S 0:00 \_ [kdevtmpfs]
8 ? S< 0:00 \_ [netns]
9 ? S< 0:00 \_ [writeback]
10 ? S 0:00 \_ [kworker/u2:1]
11 ? S< 0:00 \_ [crypto]
12 ? S 0:00 \_ [kworker/0:1]
13 ? S< 0:00 \_ [bioset]
14 ? S< 0:00 \_ [kblockd]
15 ? S 0:00 \_ [kswapd0]
68 ? S 0:00 \_ [fsnotify_mark]
221 ? S< 0:00 \_ [bioset]
229 ? S< 0:00 \_ [deferwq]
231 ? S 0:00 \_ [jbd2/ubda-8]
232 ? S< 0:00 \_ [ext4-rsv-conver]
233 ? S< 0:00 \_ [kworker/0:1H]
1 ? Ss 0:00 init [2]
271 ? S<s 0:00 udevd --daemon
297 ? S< 0:00 \_ udevd --daemon
298 ? S< 0:00 \_ udevd --daemon
549 ? Sl 0:00 /usr/sbin/rsyslogd -c4
580 ? Ss 0:00 /usr/sbin/cron
595 ? Ss 0:00 /usr/bin/dbus-daemon --system
609 ? Ss 0:00 /usr/sbin/sshd
628 tty0 Ss 0:00 /bin/login --
631 tty0 S 0:00 \_ -bash
636 tty0 R+ 0:00 \_ ps fax
629 tty1 Ss+ 0:00 /sbin/getty 38400 tty1 linux
630 ttyS0 Ss+ 0:00 /sbin/getty 115200 ttyS0 linux
Thanks,
//richard
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