Crash after 'reboot' due to 9be4fd2c7723a

[Fabio Estevam]

Rafael,

Running the 'reboot' command works fine on a 4.5 kernel running on a
mx6ul platform (ARM single core SoC), but it crashes on 4.6.

Running bisect I got 9be4fd2c7723a3057b0b39676 ("cpufreq: governor:
Replace timers with utilization update callbacks") as the first bad
commit.

Below is the output crash log.

Not sure if this issue is related to the problem reported by Guenter here:
http://lkml.iu.edu/hypermail/linux/kernel/1602.1/06075.html

Any ideas?

Thanks,

Fabio Estevam


[ 3857.373588] INFO: rcu_sched detected stalls on CPUs/tasks:
[ 3857.379155]  (detected by 0, t=2602 jiffies, g=1880, c=1879, q=29)
[ 3857.385406] All QSes seen, last rcu_sched kthread activity 2602
(355736-353134), jiffies_till_next_fqs=1, root ->qsmask 0x0
[ 3857.396562] init            R running      0   864      1 0x00000002
[ 3857.402999] Backtrace:
[ 3857.405532] [<c010b6e8>] (dump_backtrace) from [<c010b884>]
(show_stack+0x18/0x1c)
[ 3857.413125]  r6:c0d6c6d6 r5:00000001 r4:ddd9c800 r3:00000000
[ 3857.418941] [<c010b86c>] (show_stack) from [<c014fc3c>]
(sched_show_task+0x124/0x234)
[ 3857.426820] [<c014fb18>] (sched_show_task) from [<c0185e24>]
(rcu_check_callbacks+0x844/0x894)
[ 3857.435452]  r6:c0c76b40 r5:c0d14b80 r4:debd0b40
[ 3857.440189] [<c01855e0>] (rcu_check_callbacks) from [<c018884c>]
(update_process_times+0x38/0x64)
[ 3857.449081]  r10:c0d21e1c r9:debcdd10 r8:c019a230 r7:dde7bd50
r6:debce048 r5:00000000
[ 3857.457067]  r4:ddd9c800
[ 3857.459665] [<c0188814>] (update_process_times) from [<c019a174>]
(tick_sched_handle+0x50/0x54)
[ 3857.468386]  r5:00000382 r4:1c92d15d
[ 3857.472048] [<c019a124>] (tick_sched_handle) from [<c019a290>]
(tick_sched_timer+0x60/0xa8)
[ 3857.480443] [<c019a230>] (tick_sched_timer) from [<c018915c>]
(__hrtimer_run_queues+0xc0/0x1c8)
[ 3857.489162]  r7:debcdd80 r6:debcdd00 r5:debcdd8c r4:debce048
[ 3857.494969] [<c018909c>] (__hrtimer_run_queues) from [<c018998c>]
(hrtimer_interrupt+0xc8/0x22c)
[ 3857.503774]  r10:debcddd8 r9:debcddb8 r8:debcddf8 r7:debcdd00
r6:debcdd40 r5:00000003
[ 3857.511758]  r4:ffffffff
[ 3857.514354] [<c01898c4>] (hrtimer_interrupt) from [<c067d994>]
(mxc_timer_interrupt+0x3c/0x44)
[ 3857.522985]  r10:c0d6c710 r9:e0805000 r8:de41d000 r7:00000010
r6:00000000 r5:00000000
[ 3857.530969]  r4:de402440
[ 3857.533568] [<c067d958>] (mxc_timer_interrupt) from [<c0177acc>]
(handle_irq_event_percpu+0x64/0x168)
[ 3857.542809]  r4:de402500 r3:c067d958
[ 3857.546482] [<c0177a68>] (handle_irq_event_percpu) from
[<c0177c10>] (handle_irq_event+0x40/0x64)
[ 3857.555374]  r10:de406000 r9:e0805000 r8:00000001 r7:00000000
r6:c0d10330 r5:de41d060
[ 3857.563358]  r4:de41d000
[ 3857.565956] [<c0177bd0>] (handle_irq_event) from [<c017b120>]
(handle_fasteoi_irq+0xd4/0x1ac)
[ 3857.574502]  r6:c0d10330 r5:de41d060 r4:de41d000 r3:00000000
[ 3857.580305] [<c017b04c>] (handle_fasteoi_irq) from [<c017726c>]
(generic_handle_irq+0x20/0x30)
[ 3857.588937]  r7:00000000 r6:c0c746ec r5:c0d02b10 r4:00000010
[ 3857.594743] [<c017724c>] (generic_handle_irq) from [<c01773b0>]
(__handle_domain_irq+0x6c/0xe4)
[ 3857.603485] [<c0177344>] (__handle_domain_irq) from [<c01015d8>]
(gic_handle_irq+0x4c/0x9c)
[ 3857.611857]  r10:000003eb r8:c0d22000 r7:c0d02c58 r6:dde7bd50
r5:e080400c r4:e0804000
[ 3857.619858] [<c010158c>] (gic_handle_irq) from [<c010c4b8>]
(__irq_svc+0x58/0x78)
[ 3857.627367] Exception stack(0xdde7bd50 to 0xdde7bd98)
[ 3857.632450] bd40:                                     ddce911c
00000001 00000000 00000003
[ 3857.640664] bd60: ddce911c c0d02a48 ddcea000 ddce90c0 c0108044
dde7a000 00000000 dde7bdb4
[ 3857.648875] bd80: dde7bdb8 dde7bda0 c064ad44 c01b247c 20000013 ffffffff
[ 3857.655509]  r10:00000000 r9:dde7a000 r8:c0108044 r7:dde7bd84
r6:ffffffff r5:20000013
[ 3857.663494]  r4:c01b247c r3:ddd9c800
[ 3857.667167] [<c01b2448>] (irq_work_sync) from [<c064ad44>]
(cpufreq_governor_dbs+0x170/0x580)
[ 3857.675713]  r4:00000004 r3:00000001
[ 3857.679384] [<c064abd4>] (cpufreq_governor_dbs) from [<c06480e4>]
(cpufreq_governor+0x64/0x120)
[ 3857.688103]  r10:00000000 r9:dde7a000 r8:c0108044 r7:c1556f80
r6:00000002 r5:ddcea000
[ 3857.696088]  r4:c0d4c5dc
[ 3857.698684] [<c0648080>] (cpufreq_governor) from [<c06493c4>]
(cpufreq_suspend+0x70/0x128)
[ 3857.706967]  r6:c0d4c328 r5:ddcea0dc r4:ddcea000 r3:ddd9c800
[ 3857.712777] [<c0649354>] (cpufreq_suspend) from [<c04da71c>]
(syscore_shutdown+0x4c/0x80)
[ 3857.720976]  r8:c0108044 r7:00000000 r6:c0d6e020 r5:c0d315a8
r4:c0d4c2fc r3:00000000
[ 3857.728895] [<c04da6d0>] (syscore_shutdown) from [<c0147aa8>]
(kernel_restart+0x1c/0x58)
[ 3857.737007]  r6:c0d13074 r5:4321fedc r4:00000000 r3:de434900
[ 3857.742805] [<c0147a8c>] (kernel_restart) from [<c0147cc4>]
(SyS_reboot+0x18c/0x1e4)
[ 3857.750569]  r4:01234567 r3:01234567
[ 3857.754234] [<c0147b38>] (SyS_reboot) from [<c0107ea0>]
(ret_fast_syscall+0x0/0x1c)
[ 3857.761910]  r7:00000058 r6:00000000 r5:00000000 r4:00000000
[ 3857.767707] rcu_sched kthread starved for 2602 jiffies! g1880 c1879
f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0
[ 3857.777123] rcu_sched       R running      0     7      2 0x00000000
[ 3857.783558] Backtrace:
[ 3857.786076] [<c08f488c>] (__schedule) from [<c08f50d8>] (schedule+0x3c/0xa0)
[ 3857.793148]  r10:00000001 r9:00000003 r8:c0d02100 r7:0005636f
r6:debcd4c0 r5:debcd4c0
[ 3857.801133]  r4:de487e9c
[ 3857.803728] [<c08f509c>] (schedule) from [<c08f941c>]
(schedule_timeout+0x138/0x1cc)
[ 3857.811509] [<c08f92e4>] (schedule_timeout) from [<c0184bf0>]
(rcu_gp_kthread+0x3b0/0x894)
[ 3857.819794]  r8:00000000 r7:000002b8 r6:00000001 r5:c0d14e10 r4:c0d14b80
[ 3857.826667] [<c0184840>] (rcu_gp_kthread) from [<c0144e7c>]
(kthread+0xd8/0xf4)
[ 3857.833997]  r7:c0184840
[ 3857.836593] [<c0144da4>] (kthread) from [<c0107f30>]
(ret_from_fork+0x14/0x24)
[ 3857.843836]  r7:00000000 r6:00000000 r5:c0144da4 r4:de435040