Re: [Xen-devel] [PATCH 1/2] ACPI: intel-idle: Don't register CPU notifier if we are not running.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Tue, Jan 15, 2013 at 11:33:28PM +0100, Rafael J. Wysocki wrote:
> On Tuesday, January 15, 2013 05:23:23 PM Konrad Rzeszutek Wilk wrote:
> > The 'intel_idle_probe' probes the CPU and sets the CPU notifier.
> > But if later on during the module initialization we fail (say
> > in cpuidle_register_driver) we stop loading but we neglected
> > to unregister the CPU notifier. This means that during CPU
> > hotplug events the system will fail:
> 
> This really is for Len, but it appears to be obviously correct, so I'll
> take it as a v3.8 fix if Len doesn't object.
> 
> I suppose we need that in -stable too?

Yes please. 3.6 and onwards.

Thank you!
> 
> Rafael
> 
> 
> > calling  intel_idle_init+0x0/0x326 @ 1
> > intel_idle: MWAIT substates: 0x1120
> > intel_idle: v0.4 model 0x2A
> > intel_idle: lapic_timer_reliable_states 0xffffffff
> > intel_idle: intel_idle yielding to none
> > initcall intel_idle_init+0x0/0x326 returned -19 after 14 usecs
> > 
> > ... some time later, offlining and onlining a CPU:
> > 
> > cpu 3 spinlock event irq 62
> > BUG: unable to ] __cpuidle_register_device+0x1c/0x120
> > PGD 99b8b067 PUD 99b95067 PMD 0
> > Oops: 0000 [#1] SMP
> > Modules linked in: xen_evtchn nouveau mxm_wmi wmi radeon ttm i915 fbcon 
> > tileblit font atl1c bitblit softcursor drm_kms_helper video xen_blkfront 
> > xen_netfront fb_sys_fops sysimgblt sysfillrect syscopyarea xenfs 
> > xen_privcmd mperf
> > CPU 0
> > Pid: 2302, comm: udevd Not tainted 3.8.0-rc3upstream-00249-g09ad159 #1 MSI 
> > MS-7680/H61M-P23 (MS-7680)
> > RIP: e030:[<ffffffff814d956c>]  [<ffffffff814d956c>] 
> > __cpuidle_register_device+0x1c/0x120
> > RSP: e02b:ffff88009dacfcb8  EFLAGS: 00010286
> > RAX: 0000000000000000 RBX: ffff880105380000 RCX: 000000000000001c
> > RDX: 0000000000000000 RSI: 0000000000000055 RDI: ffff880105380000
> > RBP: ffff88009dacfce8 R08: ffffffff81a4f048 R09: 0000000000000008
> > R10: 0000000000000008 R11: 0000000000000000 R12: ffff880105380000
> > R13: 00000000ffffffdd R14: 0000000000000000 R15: ffffffff81a523d0
> > FS:  00007f37bd83b7a0(0000) GS:ffff880105200000(0000) knlGS:0000000000000000
> > CS:  e033 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 0000000000000008 CR3: 00000000a09ea000 CR4: 0000000000042660
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > Process udevd (pid: 2302, threadinfo ffff88009dace000, task 
> > ffff88009afb47f0)
> > Stack:
> >  ffffffff8107f2d0 ffffffff810c2fb7 ffff88009dacfce8 00000000ffffffea
> >  ffff880105380000 00000000ffffffdd ffff88009dacfd08 ffffffff814d9882
> >  0000000000000003 ffff880105380000 ffff88009dacfd28 ffffffff81340afd
> > Call Trace:
> >  [<ffffffff8107f2d0>] ? collect_cpu_info_local+0x30/0x30
> >  [<ffffffff810c2fb7>] ? __might_sleep+0xe7/0x100
> >  [<ffffffff814d9882>] cpuidle_register_device+0x32/0x70
> >  [<ffffffff81340afd>] intel_idle_cpu_init+0xad/0x110
> >  [<ffffffff81340bc8>] cpu_hotplug_notify+0x68/0x80
> >  [<ffffffff8166023d>] notifier_call_chain+0x4d/0x70
> >  [<ffffffff810bc369>] __raw_notifier_call_chain+0x9/0x10
> >  [<ffffffff81094a4b>] __cpu_notify+0x1b/0x30
> >  [<ffffffff81652cf7>] _cpu_up+0x103/0x14b
> >  [<ffffffff81652e18>] cpu_up+0xd9/0xec
> >  [<ffffffff8164a254>] store_online+0x94/0xd0
> >  [<ffffffff814122fb>] dev_attr_store+0x1b/0x20
> >  [<ffffffff81216404>] sysfs_write_file+0xf4/0x170
> >  [<ffffffff811a1024>] vfs_write+0xb4/0x130
> >  [<ffffffff811a17ea>] sys_write+0x5a/0xa0
> >  [<ffffffff816643a9>] system_call_fastpath+0x16/0x1b
> > Code: 03 18 00 c9 c3 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 48 83 ec 30 
> > 48 89 5d e8 4c 89 65 f0 48 89 fb 4c 89 6d f8 e8 84 08 00 00 <48> 8b 78 08 
> > 49 89 c4 e8 f8 7f c1 ff 89 c2 b8 ea ff ff ff 84 d2
> > RIP  [<ffffffff814d956c>] __cpuidle_register_device+0x1c/0x120
> >  RSP <ffff88009dacfcb8>
> > 
> > This patch fixes it by moving the CPU notifier registration
> > as the last item to be done by the module.
> > 
> > Cc: stable@xxxxxxxxxxxxxxx # for 3.6 and above
> > Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> > Cc: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
> > Cc: Rafael J. Wysocki <rjw@xxxxxxx>
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > ---
> >  drivers/idle/intel_idle.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
> > index 4ba384f..2df9414 100644
> > --- a/drivers/idle/intel_idle.c
> > +++ b/drivers/idle/intel_idle.c
> > @@ -448,8 +448,6 @@ static int intel_idle_probe(void)
> >     else
> >             on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
> >  
> > -   register_cpu_notifier(&cpu_hotplug_notifier);
> > -
> >     pr_debug(PREFIX "v" INTEL_IDLE_VERSION
> >             " model 0x%X\n", boot_cpu_data.x86_model);
> >  
> > @@ -612,6 +610,7 @@ static int __init intel_idle_init(void)
> >                     return retval;
> >             }
> >     }
> > +   register_cpu_notifier(&cpu_hotplug_notifier);
> >  
> >     return 0;
> >  }
> > 
> -- 
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.

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