On 10/08/2013 10:07 PM, Geert Uytterhoeven wrote:
> On Sun, Oct 6, 2013 at 11:01 PM, Toralf Förster <toralf.foers...@gmx.de>
> wrote:
>>> Hmm, now pages_dirtied is zero, according to the backtrace, but the BUG_ON()
>>> asserts its strict positive?!?
>>>
>>> Can you please try the following instead of the BUG_ON():
>>>
>>> if (pause < 0) {
>>> printk("pages_dirtied = %lu\n", pages_dirtied);
>>> printk("task_ratelimit = %lu\n", task_ratelimit);
>>> printk("pause = %ld\n", pause);
>>> }
>>>
>>> Gr{oetje,eeting}s,
>>>
>>> Geert
>> I tried it in different ways already - I'm completely unsuccessful in
>> getting any printk output.
>> As soon as the issue happens I do have a
>>
>> BUG: soft lockup - CPU#0 stuck for 22s! [trinity-child0:1521]
>>
>> at stderr of the UML and then no further input is accepted. With
>> uml_mconsole I'm however able
>> to run very basic commands like a crash dump, sysrq ond so on.
>
> You may get an idea of the magnitude of pages_dirtied by using a chain of
> BUG_ON()s, like:
>
> BUG_ON(pages_dirtied > 2000000000);
> BUG_ON(pages_dirtied > 1000000000);
> BUG_ON(pages_dirtied > 100000000);
> BUG_ON(pages_dirtied > 10000000);
> BUG_ON(pages_dirtied > 1000000);
>
> Probably 1 million is already too much for normal operation?
>
period = HZ * pages_dirtied / task_ratelimit;
BUG_ON(pages_dirtied > 2000000000);
BUG_ON(pages_dirtied > 1000000000); <-------------- this
is line 1467
the back trace is :
tfoerste@n22 ~/devel/linux $ gdb --core=/mnt/ramdisk/core
/home/tfoerste/devel/linux/linux -batch -ex bt
[New LWP 6911]
Core was generated by `/home/tfoerste/devel/linux/linux earlyprintk
ubda=/home/tfoerste/virtual/uml/tr'.
Program terminated with signal 6, Aborted.
#0 0xb77a7424 in __kernel_vsyscall ()
#0 0xb77a7424 in __kernel_vsyscall ()
#1 0x083bdf35 in kill ()
#2 0x0807296d in uml_abort () at arch/um/os-Linux/util.c:93
#3 0x08072ca5 in os_dump_core () at arch/um/os-Linux/util.c:148
#4 0x080623c4 in panic_exit (self=0x85c1558 <panic_exit_notifier>, unused1=0,
unused2=0x85f76e0 <buf.16221>) at arch/um/kernel/um_arch.c:240
#5 0x0809ba86 in notifier_call_chain (nl=0x0, val=0, v=0x85f76e0 <buf.16221>,
nr_to_call=-2, nr_calls=0x0) at kernel/notifier.c:93
#6 0x0809bba1 in __atomic_notifier_call_chain (nh=0x85f76c4
<panic_notifier_list>, val=0, v=0x85f76e0 <buf.16221>, nr_to_call=0,
nr_calls=0x0) at kernel/notifier.c:182
#7 0x0809bbdf in atomic_notifier_call_chain (nh=0x0, val=0, v=0x0) at
kernel/notifier.c:191
#8 0x0841b5bc in panic (fmt=0x0) at kernel/panic.c:130
#9 0x0841c470 in balance_dirty_pages (pages_dirtied=23, mapping=<optimized
out>) at mm/page-writeback.c:1467
#10 0x080d3595 in balance_dirty_pages_ratelimited (mapping=0x6) at
mm/page-writeback.c:1661
#11 0x080e4a3f in __do_fault (mm=0x45ba3600, vma=0x48777b90,
address=1084678144, pmd=0x0, pgoff=0, flags=0, orig_pte=<incomplete type>) at
mm/memory.c:3452
#12 0x080e6e0f in do_linear_fault (orig_pte=..., flags=<optimized out>,
pmd=<optimized out>, address=<optimized out>, vma=<optimized out>,
mm=<optimized out>, page_table=<optimized out>) at mm/memory.c:3486
#13 handle_pte_fault (flags=<optimized out>, pmd=<optimized out>,
pte=<optimized out>, address=<optimized out>, vma=<optimized out>,
mm=<optimized out>) at mm/memory.c:3710
#14 __handle_mm_fault (flags=<optimized out>, address=<optimized out>,
vma=<optimized out>, mm=<optimized out>) at mm/memory.c:3845
#15 handle_mm_fault (mm=0x45ba3600, vma=0x487034c8, address=1084678144,
flags=1) at mm/memory.c:3868
#16 0x080e7817 in __get_user_pages (tsk=0x48705800, mm=0x45ba3600,
start=1084678144, nr_pages=1025, gup_flags=519, pages=0x48558000, vmas=0x0,
nonblocking=0x0) at mm/memory.c:1822
#17 0x080e7ae3 in get_user_pages (tsk=0x0, mm=0x0, start=0, nr_pages=0,
write=1, force=0, pages=0x48777b90, vmas=0x6) at mm/memory.c:2019
#18 0x08143dc6 in aio_setup_ring (ctx=<optimized out>) at fs/aio.c:340
#19 ioctx_alloc (nr_events=<optimized out>) at fs/aio.c:605
#20 SYSC_io_setup (ctxp=<optimized out>, nr_events=<optimized out>) at
fs/aio.c:1122
#21 SyS_io_setup (nr_events=65535, ctxp=135081984) at fs/aio.c:1105
#22 0x08062984 in handle_syscall (r=0x487059d4) at
arch/um/kernel/skas/syscall.c:35
#23 0x08074fb5 in handle_trap (local_using_sysemu=<optimized out>,
regs=<optimized out>, pid=<optimized out>) at
arch/um/os-Linux/skas/process.c:198
#24 userspace (regs=0x487059d4) at arch/um/os-Linux/skas/process.c:431
#25 0x0805f750 in fork_handler () at arch/um/kernel/process.c:160
#26 0x00000000 in ?? ()
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> ge...@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like
> that.
> -- Linus Torvalds
>
--
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
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