Re: Fw: Re: 2.6.21-rc5-mm3

[Andi Kleen <ak@suse.de>]

> 
> BUG: NMI Watchdog detected LOCKUP on CPU0, eip c014ce9c, registers:

I suspect it is just because his console is too slow and then unwinding
took too long and it happened to hit the unwinder. 

You did use a slow console, right?

I suppose it just needs a strategic touch_nmi_watchdog. Will add that.

> Modules linked in: ide_cd cdrom rtc unix
> CPU:    0
> EIP:    0060:[<c014ce9c>]    Not tainted VLI
> EFLAGS: 00000093   (2.6.21-rc5-mm3 #10)
> EIP is at read_pointer+0x49/0x2d8
> eax: c7a8dd04   ebx: 00000000   ecx: 00000000   edx: c043d19c
> esi: c043d184   edi: c043d19c   ebp: c7a8dbf4   esp: c7a8dbbc
> ds: 007b   es: 007b   fs: 00d8  gs: 0033  ss: 0068
> Process udevd (pid: 864, ti=c7a8c000 task=c97cd4d0 task.ti=c7a8c000)
> Stack: 0000000b c7a8dc70 c7a8dbf4 c014d6d0 c7a8dd04 c043e454 c7a8dbf4 c011fdd1 
>        c043e404 c043e454 c043d190 0005cd94 c043d184 c7a8dd04 c7a8dd14 c014dd3a 
>        00000000 00000000 00000000 00000000 c7a8df44 c7a8dd74 c741eefb 00000008 
> Call Trace:
>  [<c014dd3a>] unwind+0x414/0xfa2
>  [<c010510d>] dump_trace_unwind+0xb4/0xe5
>  [<c014ce4d>] unwind_init_running+0x25/0x2b
>  [<c01051a1>] dump_trace+0x63/0x1eb
>  [<c010ad39>] save_stack_trace+0x23/0x42
>  [<c01393c9>] update_cpu_base_expires_next+0x56/0x5a
>  [<c013a475>] hrtimer_interrupt+0x17c/0x1b8
>  [<c0115e8e>] smp_apic_timer_interrupt+0x72/0x85
>  [<c0104bef>] apic_timer_interrupt+0x33/0x38
>  [<c014320c>] lock_release+0x1d2/0x1da
>  [<c013a7ef>] up_read+0x19/0x2e
>  [<c011b800>] do_page_fault+0x28f/0x55b
>  [<c034d191>] error_code+0x79/0x80
>  [<c020c23e>] __put_user_4+0x12/0x18
> DWARF2 unwinder stuck at __put_user_4+0x12/0x18
> Leftover inexact backtrace:
>  [<c01040d6>] ret_from_fork+0x6/0x1c

Hmpf. I saw it once in child_rip here too. Then I wanted to reproduce it to report
properly and couldn't again. I had a few other backtraces that were all non stuck
with child_rip then on essentially the same kernel. Something weird is going on.

>  [<c013a475>] hrtimer_interrupt+0x17c/0x1b8
>  [<c0115e8e>] smp_apic_timer_interrupt+0x72/0x85
>  [<c0104bef>] apic_timer_interrupt+0x33/0x38
>  [<c020c184>] __get_user_4+0x14/0x17
> DWARF2 unwinder stuck at __get_user_4+0x14/0x17
> Leftover inexact backtrace:

Now that is weird. Never seen before. Jan, any ideas?

What is your gcc/compiler, Michal?

-Andi


Were there any strange binutils in use, Michal?

>  [<c018b42f>] do_execve+0xdd/0x210
>  [<c0102497>] sys_execve+0x3f/0x62
>  [<c01041c2>] sysenter_past_esp+0x5f/0x99