Re: [ANNOUNCE] 3.8-rc4-nohz3

From: Frederic Weisbecker
Date: Thu Mar 07 2013 - 18:59:26 EST


2013/1/23 Hakan Akkan <hakanakkan@xxxxxxxxx>:
> Hi,
>
> This WARN_ON is triggered for every full nohz CPU in the system during
> AP boot in a 16 core machine:

Yeah it happens because we are enqueuing a timer to an offline CPU.
I'm trying to fix it, tell me if you still see the warning on the next
version.

Thanks!

>
> [ 0.336895] ------------[ cut here ]------------
> [ 0.341508] WARNING: at arch/x86/kernel/smp.c:123
> native_smp_send_reschedule+0x4f/0x60()
> [ 0.349578] Hardware name: X8DTG-D
> [ 0.315066] smpboot: Booting Node 0, Processors #1
> [ 0.352978] Modules linked in:
> [ 0.356233] Pid: 0, comm: swapper/1 Not tainted 3.8.0-rc4+ #3
> [ 0.361959] Call Trace:
> [ 0.364404] [<ffffffff8103c4fa>] warn_slowpath_common+0x7a/0xb0
> [ 0.370399] [<ffffffff8103c545>] warn_slowpath_null+0x15/0x20
> [ 0.376213] [<ffffffff8102435f>] native_smp_send_reschedule+0x4f/0x60
> [ 0.382723] [<ffffffff8106b328>] wake_up_nohz_cpu+0x78/0x80
> [ 0.388374] [<ffffffff8104c33a>] add_timer_on+0x8a/0xf0
> [ 0.393679] [<ffffffff8101c6f4>] mce_start_timer+0x64/0x70
> [ 0.399241] [<ffffffff8101c752>] __mcheck_cpu_init_timer+0x52/0x60
> [ 0.405490] [<ffffffff817d804a>] mcheck_cpu_init+0x360/0x3d9
> [ 0.411226] [<ffffffff817d6160>] identify_cpu+0x39d/0x3ba
> [ 0.416696] [<ffffffff817d6193>] identify_secondary_cpu+0x16/0x1d
> [ 0.422855] [<ffffffff817d9730>] smp_store_cpu_info+0x38/0x3a
> [ 0.428672] [<ffffffff817d981a>] start_secondary+0xe8/0x192
> [ 0.434317] ---[ end trace 17bfa0d8291c432e ]---
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