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Date:   Fri, 13 Apr 2018 00:39:04 +0200
From:   Niklas =?iso-8859-1?Q?S=F6derlund?= 
        <niklas.soderlund@ragnatech.se>
To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     i@linaro.org, Heiner Kallweit <hkallweit1@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@redhat.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-renesas-soc@vger.kernel.org
Subject: Re: Potential problem with 31e77c93e432dec7 ("sched/fair: Update
 blocked load when newly idle")
Message-ID: <20180412223904.GJ12256@bigcity.dyn.berto.se>
References: <20180412091822.GG12256@bigcity.dyn.berto.se>
 <CAKfTPtAE3qeWcTdT-WL8nrbZmP_+OaxPyyjUfVCzn=rax9tQZQ@mail.gmail.com>
 <20180412111519.GH12256@bigcity.dyn.berto.se>
 <20180412133031.GA551@linaro.org>
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Hi Vincent,

Thanks for helping trying to figure this out.

On 2018-04-12 15:30:31 +0200, Vincent Guittot wrote:

[snip]

> 
> I'd like to narrow the problem a bit more with the 2 patchies aboves. Can you try
> them separatly on top of c18bb396d3d261eb ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net"))
> and check if one of them fixes the problem ?i

I tried your suggested changes based on top of c18bb396d3d261eb.

> 
> (They should apply on linux-next as well)
> 
> First patch always kick ilb instead of doing ilb on local cpu before entering idle
> 
> ---
>  kernel/sched/fair.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 0951d1c..b21925b 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9739,8 +9739,7 @@ static void nohz_newidle_balance(struct rq *this_rq)
>  	 * candidate for ilb instead of waking up another idle CPU.
>  	 * Kick an normal ilb if we failed to do the update.
>  	 */
> -	if (!_nohz_idle_balance(this_rq, NOHZ_STATS_KICK, CPU_NEWLY_IDLE))
> -		kick_ilb(NOHZ_STATS_KICK);
> +	kick_ilb(NOHZ_STATS_KICK);
>  	raw_spin_lock(&this_rq->lock);
>  }

This change don't seem to effect the issue. I can still get the single 
ssh session and the system to lockup by hitting the return key. And 
opening a second ssh session immediately unblocks both the first ssh 
session and the serial console. And I can still trigger the console 
warning by just letting the system be once it locks-up. I do have 
just as before reset the system a few times to trigger the issue.

[  245.351693] INFO: rcu_sched detected stalls on CPUs/tasks:
[  245.357199] 	0-...!: (1 GPs behind) idle=93c/0/0 softirq=2224/2225 fqs=0 
[  245.363988] 	(detected by 1, t=3025 jiffies, g=337, c=336, q=10)
[  245.370003] Sending NMI from CPU 1 to CPUs 0:
[  245.374368] NMI backtrace for cpu 0
[  245.374377] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-10930-ged741fb4567c816f #42
[  245.374379] Hardware name: Generic R8A7791 (Flattened Device Tree)
[  245.374393] PC is at arch_cpu_idle+0x24/0x40
[  245.374397] LR is at arch_cpu_idle+0x34/0x40
[  245.374400] pc : [<c0108554>]    lr : [<c0108564>]    psr: 60050013
[  245.374403] sp : c0b01f40  ip : c0b01f50  fp : c0b01f4c
[  245.374405] r10: c0a56a38  r9 : e7fffbc0  r8 : c0b04c00
[  245.374407] r7 : c0b04c78  r6 : c0b04c2c  r5 : ffffe000  r4 : 00000001
[  245.374410] r3 : c0119100  r2 : e77813a8  r1 : 0002d93c  r0 : 00000000
[  245.374414] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[  245.374417] Control: 10c5387d  Table: 6662006a  DAC: 00000051
[  245.374421] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-10930-ged741fb4567c816f #42
[  245.374423] Hardware name: Generic R8A7791 (Flattened Device Tree)
[  245.374425] Backtrace: 
[  245.374435] [<c010c170>] (dump_backtrace) from [<c010c3f0>] (show_stack+0x18/0x1c)
[  245.374440]  r7:c0b47278 r6:60050193 r5:00000000 r4:c0b73d80
[  245.374450] [<c010c3d8>] (show_stack) from [<c074b824>] (dump_stack+0x84/0xa4)
[  245.374456] [<c074b7a0>] (dump_stack) from [<c01087e8>] (show_regs+0x14/0x18)
[  245.374460]  r7:c0b47278 r6:c0b01ef0 r5:00000000 r4:c0bc62c8
[  245.374468] [<c01087d4>] (show_regs) from [<c0751938>] (nmi_cpu_backtrace+0xfc/0x118)
[  245.374475] [<c075183c>] (nmi_cpu_backtrace) from [<c010ef34>] (handle_IPI+0x22c/0x294)
[  245.374479]  r7:c0b47278 r6:c0b01ef0 r5:00000007 r4:c0a775fc
[  245.374488] [<c010ed08>] (handle_IPI) from [<c037cd68>] (gic_handle_irq+0x8c/0x98)
[  245.374492]  r10:c0a56a38 r9:c0b00000 r8:f0803000 r7:c0b47278 r6:c0b01ef0 r5:c0b05244
[  245.374495]  r4:f0802000 r3:00000407
[  245.374501] [<c037ccdc>] (gic_handle_irq) from [<c0101a0c>] (__irq_svc+0x6c/0x90)
[  245.374504] Exception stack(0xc0b01ef0 to 0xc0b01f38)
[  245.374507] 1ee0:                                     00000000 0002d93c e77813a8 c0119100
[  245.374512] 1f00: 00000001 ffffe000 c0b04c2c c0b04c78 c0b04c00 e7fffbc0 c0a56a38 c0b01f4c
[  245.374516] 1f20: c0b01f50 c0b01f40 c0108564 c0108554 60050013 ffffffff
[  245.374521]  r9:c0b00000 r8:c0b04c00 r7:c0b01f24 r6:ffffffff r5:60050013 r4:c0108554
[  245.374528] [<c0108530>] (arch_cpu_idle) from [<c076512c>] (default_idle_call+0x30/0x34)
[  245.374535] [<c07650fc>] (default_idle_call) from [<c014b834>] (do_idle+0xd8/0x128)
[  245.374540] [<c014b75c>] (do_idle) from [<c014baf0>] (cpu_startup_entry+0x20/0x24)
[  245.374543]  r7:c0b04c08 r6:ffffffff r5:c0b80380 r4:000000c2
[  245.374549] [<c014bad0>] (cpu_startup_entry) from [<c075fb14>] (rest_init+0x9c/0xbc)
[  245.374555] [<c075fa78>] (rest_init) from [<c0a00dc4>] (start_kernel+0x368/0x3ec)
[  245.374558]  r5:c0b80380 r4:c0b803c0
[  245.374563] [<c0a00a5c>] (start_kernel) from [<00000000>] (  (null))
[  245.375369] rcu_sched kthread starved for 3028 jiffies! g337 c336 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=1
[  245.641242] RCU grace-period kthread stack dump:
[  245.645859] rcu_sched       I    0     9      2 0x00000000
[  245.651350] Backtrace: 
[  245.653804] [<c07603f0>] (__schedule) from [<c0760b44>] (schedule+0x94/0xb8)
[  245.660857]  r10:e77903c0 r9:e77903c0 r8:ffffffff r7:e709bed4 r6:ffffded7 r5:00000000
[  245.668689]  r4:ffffe000
[  245.671227] [<c0760ab0>] (schedule) from [<c0764500>] (schedule_timeout+0x380/0x3dc)
[  245.678973]  r5:00000000 r4:00000000
[  245.682557] [<c0764180>] (schedule_timeout) from [<c017b620>] (rcu_gp_kthread+0x668/0xe2c)
[  245.690826]  r10:c0b79018 r9:00000151 r8:00000150 r7:00000001 r6:00000000 r5:c0b10ad0
[  245.698658]  r4:c0b10980
[  245.701197] [<c017afb8>] (rcu_gp_kthread) from [<c013ddd8>] (kthread+0x148/0x160)
[  245.708682]  r7:c0b10980
[  245.711218] [<c013dc90>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
[  245.718443] Exception stack(0xe709bfb0 to 0xe709bff8)
[  245.723495] bfa0:                                     00000000 00000000 00000000 00000000
[  245.731677] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[  245.739858] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[  245.746476]  r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c013dc90
[  245.754307]  r4:e7026f40
[  335.351162] INFO: rcu_sched detected stalls on CPUs/tasks:
[  335.356682] 	0-...!: (0 ticks this GP) idle=b0a/1/1073741824 softirq=2226/2226 fqs=0 
[  335.364521] 	(detected by 1, t=6027 jiffies, g=340, c=339, q=77)
[  335.370545] Sending NMI from CPU 1 to CPUs 0:
[  345.374803] NMI backtrace for cpu 1
[  345.378295] CPU: 1 PID: 1926 Comm: bash Not tainted 4.16.0-10930-ged741fb4567c816f #42
[  345.386215] Hardware name: Generic R8A7791 (Flattened Device Tree)
[  345.392395] Backtrace: 
[  345.394855] [<c010c170>] (dump_backtrace) from [<c010c3f0>] (show_stack+0x18/0x1c)
[  345.402430]  r7:00000000 r6:600f0193 r5:00000000 r4:c0b73d80
[  345.408097] [<c010c3d8>] (show_stack) from [<c074b824>] (dump_stack+0x84/0xa4)
[  345.415329] [<c074b7a0>] (dump_stack) from [<c0751940>] (nmi_cpu_backtrace+0x104/0x118)
[  345.423337]  r7:00000000 r6:00000000 r5:00000001 r4:c0bc62c8
[  345.429001] [<c075183c>] (nmi_cpu_backtrace) from [<c07519e0>] (nmi_trigger_cpumask_backtrace+0x8c/0x10c)
[  345.438572]  r7:00000000 r6:c010e4d4 r5:00000001 r4:c0b08158
[  345.444237] [<c0751954>] (nmi_trigger_cpumask_backtrace) from [<c010f0ec>] (arch_trigger_cpumask_backtrace+0x14/0x1c)
[  345.454850]  r7:c0b10980 r6:c0b04cd0 r5:00000001 r4:c0b10980
[  345.460519] [<c010f0d8>] (arch_trigger_cpumask_backtrace) from [<c017f9ac>] (rcu_dump_cpu_stacks+0xb0/0xd0)
[  345.470268] [<c017f8fc>] (rcu_dump_cpu_stacks) from [<c017e73c>] (rcu_check_callbacks+0x584/0x71c)
[  345.479232]  r10:0000004d r9:c0b03d00 r8:ffffe000 r7:00000001 r6:c0b10940 r5:e7795080
[  345.487065]  r4:c0b10980 r3:f181863e
[  345.490648] [<c017e1b8>] (rcu_check_callbacks) from [<c0184a60>] (update_process_times+0x38/0x64)
[  345.499524]  r10:e7fa9ea0 r9:e67e8000 r8:e7795e00 r7:0000004e r6:00000000 r5:e72d0640
[  345.507356]  r4:ffffe000
[  345.509903] [<c0184a28>] (update_process_times) from [<c0195bf0>] (tick_nohz_handler+0xc8/0x114)
[  345.518693]  r7:0000004e r6:146afc64 r5:e67e9d70 r4:e77917a0
[  345.524362] [<c0195b28>] (tick_nohz_handler) from [<c05c16ac>] (arch_timer_handler_virt+0x30/0x40)
[  345.533325]  r8:c0b05244 r7:00000013 r6:e7017a40 r5:00000000 r4:e7015c00
[  345.540033] [<c05c167c>] (arch_timer_handler_virt) from [<c016ecd4>] (handle_percpu_devid_irq+0xf0/0x224)
[  345.549607] [<c016ebe4>] (handle_percpu_devid_irq) from [<c016a208>] (generic_handle_irq+0x20/0x30)
[  345.558657]  r10:e7fa9ea0 r9:e67e8000 r8:e7008800 r7:00000013 r6:c0a775fc r5:00000000
[  345.566489]  r4:00000000 r3:c016ebe4
[  345.570067] [<c016a1e8>] (generic_handle_irq) from [<c016a2c0>] (__handle_domain_irq+0xa8/0xbc)
[  345.578777] [<c016a218>] (__handle_domain_irq) from [<c037cd3c>] (gic_handle_irq+0x60/0x98)
[  345.587132]  r9:e67e8000 r8:f0803000 r7:c0b47278 r6:e67e9d70 r5:c0b05244 r4:f0802000
[  345.594883] [<c037ccdc>] (gic_handle_irq) from [<c0101a0c>] (__irq_svc+0x6c/0x90)
[  345.602368] Exception stack(0xe67e9d70 to 0xe67e9db8)
[  345.607421] 9d60:                                     00000000 e6c433e8 00182b08 00000000
[  345.615603] 9d80: e6c429b4 00000087 e67e9e34 e6c434c4 00000000 00000087 e7fa9ea0 e67e9e14
[  345.623784] 9da0: 00000000 e67e9dc0 c01e0f34 c01e0f88 600f0113 ffffffff
[  345.630401]  r9:e67e8000 r8:00000000 r7:e67e9da4 r6:ffffffff r5:600f0113 r4:c01e0f88
[  345.638156] [<c01e0d84>] (filemap_map_pages) from [<c02141f0>] (handle_mm_fault+0x5c8/0x93c)
[  345.646599]  r10:e5dc5380 r9:80000007 r8:00000080 r7:b6e02000 r6:c0b04c08 r5:0000008f
[  345.654431]  r4:00000000
[  345.656968] [<c0213c28>] (handle_mm_fault) from [<c011404c>] (do_page_fault+0x17c/0x324)
[  345.665063]  r10:e5dc5380 r9:80000007 r8:e72d0640 r7:00000054 r6:e5d030c0 r5:b6e023dc
[  345.672895]  r4:e67e9fb0
[  345.675431] [<c0113ed0>] (do_page_fault) from [<c0114470>] (do_PrefetchAbort+0x4c/0xc8)
[  345.683439]  r10:00000010 r9:00179207 r8:c0b0a434 r7:e67e9fb0 r6:b6e023dc r5:c0b04c08
[  345.691271]  r4:00000007
[  345.693807] [<c0114424>] (do_PrefetchAbort) from [<c010204c>] (ret_from_exception+0x0/0x14)
[  345.702160] Exception stack(0xe67e9fb0 to 0xe67e9ff8)
[  345.707213] 9fa0:                                     00000000 000e9600 00000001 bec86544
[  345.715395] 9fc0: 00000001 bec86544 00000000 00000000 bec8654c 00179207 00000010 000e9600
[  345.723576] 9fe0: 000c8140 bec86538 0002847c b6e023dc 200f0010 ffffffff
[  345.730192]  r8:10c5387d r7:10c5387d r6:ffffffff r5:200f0010 r4:b6e023dc
[  345.737364] nfs: server 10.0.1.1 not responding, still trying
[  345.743294] nfs: server 10.0.1.1 not responding, still trying
[  345.744534] nfs: server 10.0.1.1 not responding, still trying
[  345.749262] nfs: server 10.0.1.1 OK
[  345.755391] nfs: server 10.0.1.1 OK
[  345.758641] nfs: server 10.0.1.1 OK

>  
> -- 
> 2.7.4
> 
> 
> The 2nd patch does the opposite and never kick ilb. I have always made the
> assumtpion that the problem was coming from _nohz_idle_balance() and I just
> wanted to check that's the case
> 
> ---
>  kernel/sched/fair.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 0951d1c..1766594 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9739,8 +9739,7 @@ static void nohz_newidle_balance(struct rq *this_rq)
>  	 * candidate for ilb instead of waking up another idle CPU.
>  	 * Kick an normal ilb if we failed to do the update.
>  	 */
> -	if (!_nohz_idle_balance(this_rq, NOHZ_STATS_KICK, CPU_NEWLY_IDLE))
> -		kick_ilb(NOHZ_STATS_KICK);
> +	_nohz_idle_balance(this_rq, NOHZ_STATS_KICK, CPU_NEWLY_IDLE);
>  	raw_spin_lock(&this_rq->lock);
>  }

With this change it seem more difficult to trigger the issue, I usually 
can trigger it within 2-3 rests of the system but with this applied I 
had to reset it over 5 times to trigger it. But I can still reproduce 
the lockup reliably multiple times. I would not trust my feeling that 
it's harder to reproduce with this change as the method to trigger it is 
kind of spotty and most likely due to circumstantial circumstances :-)

I can still unlock the system by starting a second ssh session and 
trigger the output on the serial console.

[  193.741481] INFO: rcu_sched detected stalls on CPUs/tasks:
[  193.746991] 	1-...!: (0 ticks this GP) idle=83c/0/0 softirq=2445/2445 fqs=0 
[  193.754041] 	(detected by 0, t=4096 jiffies, g=611, c=610, q=31)
[  193.760054] NMI backtrace for cpu 0
[  193.763546] CPU: 0 PID: 2193 Comm: bash Not tainted 4.16.0-10929-gc18bb396d3d261eb-dirty #43
[  193.771984] Hardware name: Generic R8A7791 (Flattened Device Tree)
[  193.778163] Backtrace: 
[  193.780625] [<c010c170>] (dump_backtrace) from [<c010c3f0>] (show_stack+0x18/0x1c)
[  193.788198]  r7:00000000 r6:60010193 r5:00000000 r4:c0b73d80
[  193.793865] [<c010c3d8>] (show_stack) from [<c074b864>] (dump_stack+0x84/0xa4)
[  193.801093] [<c074b7e0>] (dump_stack) from [<c0751980>] (nmi_cpu_backtrace+0x104/0x118)
[  193.809098]  r7:00000000 r6:00000000 r5:00000000 r4:c0bc62c8
[  193.814761] [<c075187c>] (nmi_cpu_backtrace) from [<c0751a20>] (nmi_trigger_cpumask_backtrace+0x8c/0x10c)
[  193.824329]  r7:00000000 r6:c010e4d4 r5:00000000 r4:c0b08158
[  193.829992] [<c0751994>] (nmi_trigger_cpumask_backtrace) from [<c010f0ec>] (arch_trigger_cpumask_backtrace+0x14/0x1c)
[  193.840603]  r7:c0b10980 r6:c0b04cd0 r5:00000000 r4:c0b10980
[  193.846268] [<c010f0d8>] (arch_trigger_cpumask_backtrace) from [<c017f9ec>] (rcu_dump_cpu_stacks+0xb0/0xd0)
[  193.856015] [<c017f93c>] (rcu_dump_cpu_stacks) from [<c017e77c>] (rcu_check_callbacks+0x584/0x71c)
[  193.864977]  r10:0000001f r9:c0b03d00 r8:ffffe000 r7:00000001 r6:c0b10940 r5:e7786080
[  193.872810]  r4:c0b10980 r3:f181863e
[  193.876392] [<c017e1f8>] (rcu_check_callbacks) from [<c0184aa0>] (update_process_times+0x38/0x64)
[  193.885268]  r10:00000000 r9:00180b98 r8:e7786e00 r7:0000002d r6:00000001 r5:e5d86180
[  193.893100]  r4:ffffe000
[  193.895642] [<c0184a68>] (update_process_times) from [<c0195c30>] (tick_nohz_handler+0xc8/0x114)
[  193.904431]  r7:0000002d r6:1bcdda00 r5:e66c7fb0 r4:e77827a0
[  193.910099] [<c0195b68>] (tick_nohz_handler) from [<c05c16ec>] (arch_timer_handler_virt+0x30/0x40)
[  193.919062]  r8:c0b05244 r7:00000013 r6:e7017a40 r5:00000000 r4:e7015c00
[  193.925769] [<c05c16bc>] (arch_timer_handler_virt) from [<c016ed14>] (handle_percpu_devid_irq+0xf0/0x224)
[  193.935343] [<c016ec24>] (handle_percpu_devid_irq) from [<c016a248>] (generic_handle_irq+0x20/0x30)
[  193.944394]  r10:00000000 r9:00180b98 r8:e7008800 r7:00000013 r6:c0a775fc r5:00000000
[  193.952225]  r4:00000000 r3:c016ec24
[  193.955803] [<c016a228>] (generic_handle_irq) from [<c016a300>] (__handle_domain_irq+0xa8/0xbc)
[  193.964513] [<c016a258>] (__handle_domain_irq) from [<c037cd7c>] (gic_handle_irq+0x60/0x98)
[  193.972869]  r9:00180b98 r8:f0803000 r7:c0b47278 r6:e66c7fb0 r5:c0b05244 r4:f0802000
[  193.980619] [<c037cd1c>] (gic_handle_irq) from [<c0101dd4>] (__irq_usr+0x54/0x80)
[  193.988105] Exception stack(0xe66c7fb0 to 0xe66c7ff8)
[  193.993157] 7fa0:                                     00000000 00000000 b6e8b79c 00000000
[  194.001339] 7fc0: 00178378 000134e0 b6e8b794 b6e8b000 b6e8b794 00180b98 00000000 b6e8b7c4
[  194.009520] 7fe0: be955190 be955170 00000000 b6db5c58 20010010 ffffffff
[  194.016137]  r9:00180b98 r8:10c5387d r7:10c5387d r6:ffffffff r5:20010010 r4:b6db5c58
[  194.023888] Sending NMI from CPU 0 to CPUs 1:
[  204.028147] NMI backtrace for cpu 1
[  204.028152] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.16.0-10929-gc18bb396d3d261eb-dirty #43
[  204.028155] Hardware name: Generic R8A7791 (Flattened Device Tree)
[  204.028164] PC is at _raw_spin_unlock_irqrestore+0x28/0x2c
[  204.028169] LR is at rcu_report_qs_rnp+0x4c/0x20c
[  204.028172] pc : [<c07653d8>]    lr : [<c01796d4>]    psr: 200e0113
[  204.028175] sp : e70a3db0  ip : e70a3dc0  fp : e70a3dbc
[  204.028177] r10: 00000264  r9 : c0b787eb  r8 : 00000001
[  204.028179] r7 : 00000002  r6 : c0b10980  r5 : c0b10980  r4 : c0b10980
[  204.028182] r3 : 000022a3  r2 : 00000264  r1 : 600e0113  r0 : c0b10980
[  204.028187] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[  204.028189] Control: 10c5387d  Table: 66b9806a  DAC: 00000051
[  204.028193] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.16.0-10929-gc18bb396d3d261eb-dirty #43
[  204.028195] Hardware name: Generic R8A7791 (Flattened Device Tree)
[  204.028197] Backtrace: 
[  204.028204] [<c010c170>] (dump_backtrace) from [<c010c3f0>] (show_stack+0x18/0x1c)
[  204.028209]  r7:c0b47278 r6:600e0193 r5:00000000 r4:c0b73d80
[  204.028215] [<c010c3d8>] (show_stack) from [<c074b864>] (dump_stack+0x84/0xa4)
[  204.028228] [<c074b7e0>] (dump_stack) from [<c01087e8>] (show_regs+0x14/0x18)
[  204.028231]  r7:c0b47278 r6:e70a3d60 r5:00000001 r4:c0bc62c8
[  204.028238] [<c01087d4>] (show_regs) from [<c0751978>] (nmi_cpu_backtrace+0xfc/0x118)
[  204.028244] [<c075187c>] (nmi_cpu_backtrace) from [<c010ef34>] (handle_IPI+0x22c/0x294)
[  204.028247]  r7:c0b47278 r6:e70a3d60 r5:00000007 r4:c0a775fc
[  204.028254] [<c010ed08>] (handle_IPI) from [<c037cda8>] (gic_handle_irq+0x8c/0x98)
[  204.028259]  r10:00000264 r9:e70a2000 r8:f0803000 r7:c0b47278 r6:e70a3d60 r5:c0b05244
[  204.028261]  r4:f0802000 r3:00000007
[  204.028267] [<c037cd1c>] (gic_handle_irq) from [<c0101a0c>] (__irq_svc+0x6c/0x90)
[  204.028270] Exception stack(0xe70a3d60 to 0xe70a3da8)
[  204.028275] 3d60: c0b10980 600e0113 00000264 000022a3 c0b10980 c0b10980 c0b10980 00000002
[  204.028280] 3d80: 00000001 c0b787eb 00000264 e70a3dbc e70a3dc0 e70a3db0 c01796d4 c07653d8
[  204.028283] 3da0: 200e0113 ffffffff
[  204.028287]  r9:e70a2000 r8:00000001 r7:e70a3d94 r6:ffffffff r5:200e0113 r4:c07653d8
[  204.028295] [<c07653b0>] (_raw_spin_unlock_irqrestore) from [<c01796d4>] (rcu_report_qs_rnp+0x4c/0x20c)
[  204.028301] [<c0179688>] (rcu_report_qs_rnp) from [<c017c188>] (rcu_process_callbacks+0x364/0x8cc)
[  204.028305]  r10:c0b03080 r9:00000000 r8:00000002 r7:600e0113 r6:c0b10980 r5:c0b10980
[  204.028306]  r4:e7795080
[  204.028312] [<c017be24>] (rcu_process_callbacks) from [<c010236c>] (__do_softirq+0x23c/0x338)
[  204.028316]  r10:c0b03080 r9:00000100 r8:c0b80ec0 r7:00000002 r6:00000009 r5:c0b030a4
[  204.028318]  r4:ffffe000
[  204.028325] [<c0102130>] (__do_softirq) from [<c0125b90>] (irq_exit+0x6c/0xd4)
[  204.028329]  r10:00000000 r9:e70a2000 r8:e7008800 r7:00000013 r6:c0a775fc r5:00000000
[  204.028331]  r4:00000000
[  204.028336] [<c0125b24>] (irq_exit) from [<c016a2e0>] (__handle_domain_irq+0x88/0xbc)
[  204.028338]  r5:00000000 r4:00000000
[  204.028344] [<c016a258>] (__handle_domain_irq) from [<c037cd7c>] (gic_handle_irq+0x60/0x98)
[  204.028348]  r9:e70a2000 r8:f0803000 r7:c0b47278 r6:e70a3f40 r5:c0b05244 r4:f0802000
[  204.028354] [<c037cd1c>] (gic_handle_irq) from [<c0101a0c>] (__irq_svc+0x6c/0x90)
[  204.028356] Exception stack(0xe70a3f40 to 0xe70a3f88)
[  204.028361] 3f40: 00000000 00013844 e77903a8 c0119100 00000002 ffffe000 c0b04c2c c0b04c78
[  204.028367] 3f60: 4000406a 413fc0f2 00000000 e70a3f9c e70a3fa0 e70a3f90 c0108564 c0108554
[  204.028370] 3f80: 600e0013 ffffffff
[  204.028374]  r9:e70a2000 r8:4000406a r7:e70a3f74 r6:ffffffff r5:600e0013 r4:c0108554
[  204.028381] [<c0108530>] (arch_cpu_idle) from [<c076516c>] (default_idle_call+0x30/0x34)
[  204.028388] [<c076513c>] (default_idle_call) from [<c014b834>] (do_idle+0xd8/0x128)
[  204.028392] [<c014b75c>] (do_idle) from [<c014baf0>] (cpu_startup_entry+0x20/0x24)
[  204.028396]  r7:c0b80750 r6:10c0387d r5:00000051 r4:00000085
[  204.028401] [<c014bad0>] (cpu_startup_entry) from [<c010eacc>] (secondary_start_kernel+0x10c/0x12c)
[  204.028406] [<c010e9c0>] (secondary_start_kernel) from [<4010250c>] (0x4010250c)
[  204.028408]  r5:00000051 r4:6709406a

>  
> -- 
> 2.7.4
> 
> 
> Thanks,
> Vincent
> 
> > >
> > > 
> > > Regards,
> > > Vincent
> > > >
> > > > 1. c18bb396d3d261eb ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net"))
> > > > 2. 31e77c93e432dec7 ("sched/fair: Update blocked load when newly idle")
> > > >
> > > > --
> > > > Regards,
> > > > Niklas S?derlund
> > 
> > -- 
> > Regards,
> > Niklas S?derlund

-- 
Regards,
Niklas S?derlund