On (Fri) 22 Aug 2014 [18:06:51], Amit Shah wrote:
> On (Fri) 22 Aug 2014 [17:54:53], Amit Shah wrote:
> > On (Mon) 18 Aug 2014 [21:01:49], Paul E. McKenney wrote:
> >
> > > The odds are low over the next few days. I am adding nastier rcutorture
> > > testing, however. It would still be very good to get debug information
> > > from your setup. One approach would be to convert the trace function
> > > calls into printk(), if that would help.
> >
> > I added a few printks on the lines of the traces in cases where
> > rcu_nocb_poll was checked -- since that reproduces the hang. Are the
> > following traces sufficient, or should I keep adding more printks?
> >
> > In the case of rcu-trace-nopoll.txt, the messages stop after a while
> > (when the guest locks up hard). That's when I kill the qemu process.
>
> And this is bt from gdb when the endless
>
> RCUDEBUG __call_rcu_nocb_enqueue 2146 rcu_preempt 0 WakeNot
>
> messages are being spewed.
>
> I can't time it, but hope it gives some indication along with the printks.
... and after the system 'locks up', this is the state it's in:
^C
Program received signal SIGINT, Interrupt.
native_safe_halt () at ./arch/x86/include/asm/irqflags.h:50
50 }
(gdb) bt
#0 native_safe_halt () at ./arch/x86/include/asm/irqflags.h:50
#1 0xffffffff8100b9c1 in arch_safe_halt () at
./arch/x86/include/asm/paravirt.h:111
#2 default_idle () at arch/x86/kernel/process.c:311
#3 0xffffffff8100c107 in arch_cpu_idle () at arch/x86/kernel/process.c:302
#4 0xffffffff8106a25a in cpuidle_idle_call () at kernel/sched/idle.c:120
#5 cpu_idle_loop () at kernel/sched/idle.c:220
#6 cpu_startup_entry (state=<optimized out>) at kernel/sched/idle.c:268
#7 0xffffffff813e068b in rest_init () at init/main.c:418
#8 0xffffffff81a8cf5a in start_kernel () at init/main.c:680
#9 0xffffffff81a8c4ba in x86_64_start_reservations (real_mode_data=<optimized
out>) at arch/x86/kernel/head64.c:193
#10 0xffffffff81a8c607 in x86_64_start_kernel (real_mode_data=0x13f90
<cpu_lock_stats+29184> <error: Cannot access memory at address 0x13f90>)
at arch/x86/kernel/head64.c:182
#11 0x0000000000000000 in ?? ()
Wondering why it's doing this. Am stepping through
cpu_startup_entry() to see if I get any clues.
Amit
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