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6577e42a3e
linux/kernel/sched
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Peter Zijlstra 6577e42a3e sched/clock: Fix up clear_sched_clock_stable() 
The below tells us the static_key conversion has a problem; since the
exact point of clearing that flag isn't too important, delay the flip
and use a workqueue to process it.

[ ] TSC synchronization [CPU#0 -> CPU#22]:
[ ] Measured 8 cycles TSC warp between CPUs, turning off TSC clock.
[ ]
[ ] ======================================================
[ ] [ INFO: possible circular locking dependency detected ]
[ ] 3.13.0-rc3-01745-g848b0d0322cb-dirty #637 Not tainted
[ ] -------------------------------------------------------
[ ] swapper/0/1 is trying to acquire lock:
[ ]  (jump_label_mutex){+.+...}, at: [<ffffffff8115a637>] jump_label_lock+0x17/0x20
[ ]
[ ] but task is already holding lock:
[ ]  (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109408b>] cpu_hotplug_begin+0x2b/0x60
[ ]
[ ] which lock already depends on the new lock.
[ ]
[ ]
[ ] the existing dependency chain (in reverse order) is:
[ ]
[ ] -> #1 (cpu_hotplug.lock){+.+.+.}:
[ ]        [<ffffffff810def00>] lock_acquire+0x90/0x130
[ ]        [<ffffffff81661f83>] mutex_lock_nested+0x63/0x3e0
[ ]        [<ffffffff81093fdc>] get_online_cpus+0x3c/0x60
[ ]        [<ffffffff8104cc67>] arch_jump_label_transform+0x37/0x130
[ ]        [<ffffffff8115a3cf>] __jump_label_update+0x5f/0x80
[ ]        [<ffffffff8115a48d>] jump_label_update+0x9d/0xb0
[ ]        [<ffffffff8115aa6d>] static_key_slow_inc+0x9d/0xb0
[ ]        [<ffffffff810c0f65>] sched_feat_set+0xf5/0x100
[ ]        [<ffffffff810c5bdc>] set_numabalancing_state+0x2c/0x30
[ ]        [<ffffffff81d12f3d>] numa_policy_init+0x1af/0x1b7
[ ]        [<ffffffff81cebdf4>] start_kernel+0x35d/0x41f
[ ]        [<ffffffff81ceb5a5>] x86_64_start_reservations+0x2a/0x2c
[ ]        [<ffffffff81ceb6a2>] x86_64_start_kernel+0xfb/0xfe
[ ]
[ ] -> #0 (jump_label_mutex){+.+...}:
[ ]        [<ffffffff810de141>] __lock_acquire+0x1701/0x1eb0
[ ]        [<ffffffff810def00>] lock_acquire+0x90/0x130
[ ]        [<ffffffff81661f83>] mutex_lock_nested+0x63/0x3e0
[ ]        [<ffffffff8115a637>] jump_label_lock+0x17/0x20
[ ]        [<ffffffff8115aa3b>] static_key_slow_inc+0x6b/0xb0
[ ]        [<ffffffff810ca775>] clear_sched_clock_stable+0x15/0x20
[ ]        [<ffffffff810503b3>] mark_tsc_unstable+0x23/0x70
[ ]        [<ffffffff810772cb>] check_tsc_sync_source+0x14b/0x150
[ ]        [<ffffffff81076612>] native_cpu_up+0x3a2/0x890
[ ]        [<ffffffff810941cb>] _cpu_up+0xdb/0x160
[ ]        [<ffffffff810942c9>] cpu_up+0x79/0x90
[ ]        [<ffffffff81d0af6b>] smp_init+0x60/0x8c
[ ]        [<ffffffff81cebf42>] kernel_init_freeable+0x8c/0x197
[ ]        [<ffffffff8164e32e>] kernel_init+0xe/0x130
[ ]        [<ffffffff8166beec>] ret_from_fork+0x7c/0xb0
[ ]
[ ] other info that might help us debug this:
[ ]
[ ]  Possible unsafe locking scenario:
[ ]
[ ]        CPU0                    CPU1
[ ]        ----                    ----
[ ]   lock(cpu_hotplug.lock);
[ ]                                lock(jump_label_mutex);
[ ]                                lock(cpu_hotplug.lock);
[ ]   lock(jump_label_mutex);
[ ]
[ ]  *** DEADLOCK ***
[ ]
[ ] 2 locks held by swapper/0/1:
[ ]  #0:  (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff81094037>] cpu_maps_update_begin+0x17/0x20
[ ]  #1:  (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109408b>] cpu_hotplug_begin+0x2b/0x60
[ ]
[ ] stack backtrace:
[ ] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3-01745-g848b0d0322cb-dirty #637
[ ] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[ ]  ffffffff82c9c270 ffff880236843bb8 ffffffff8165c5f5 ffffffff82c9c270
[ ]  ffff880236843bf8 ffffffff81658c02 ffff880236843c80 ffff8802368586a0
[ ]  ffff880236858678 0000000000000001 0000000000000002 ffff880236858000
[ ] Call Trace:
[ ]  [<ffffffff8165c5f5>] dump_stack+0x4e/0x7a
[ ]  [<ffffffff81658c02>] print_circular_bug+0x1f9/0x207
[ ]  [<ffffffff810de141>] __lock_acquire+0x1701/0x1eb0
[ ]  [<ffffffff816680ff>] ? __atomic_notifier_call_chain+0x8f/0xb0
[ ]  [<ffffffff810def00>] lock_acquire+0x90/0x130
[ ]  [<ffffffff8115a637>] ? jump_label_lock+0x17/0x20
[ ]  [<ffffffff8115a637>] ? jump_label_lock+0x17/0x20
[ ]  [<ffffffff81661f83>] mutex_lock_nested+0x63/0x3e0
[ ]  [<ffffffff8115a637>] ? jump_label_lock+0x17/0x20
[ ]  [<ffffffff8115a637>] jump_label_lock+0x17/0x20
[ ]  [<ffffffff8115aa3b>] static_key_slow_inc+0x6b/0xb0
[ ]  [<ffffffff810ca775>] clear_sched_clock_stable+0x15/0x20
[ ]  [<ffffffff810503b3>] mark_tsc_unstable+0x23/0x70
[ ]  [<ffffffff810772cb>] check_tsc_sync_source+0x14b/0x150
[ ]  [<ffffffff81076612>] native_cpu_up+0x3a2/0x890
[ ]  [<ffffffff810941cb>] _cpu_up+0xdb/0x160
[ ]  [<ffffffff810942c9>] cpu_up+0x79/0x90
[ ]  [<ffffffff81d0af6b>] smp_init+0x60/0x8c
[ ]  [<ffffffff81cebf42>] kernel_init_freeable+0x8c/0x197
[ ]  [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ]  [<ffffffff8164e32e>] kernel_init+0xe/0x130
[ ]  [<ffffffff8166beec>] ret_from_fork+0x7c/0xb0
[ ]  [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ] ------------[ cut here ]------------
[ ] WARNING: CPU: 0 PID: 1 at /usr/src/linux-2.6/kernel/smp.c:374 smp_call_function_many+0xad/0x300()
[ ] Modules linked in:
[ ] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3-01745-g848b0d0322cb-dirty #637
[ ] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[ ]  0000000000000009 ffff880236843be0 ffffffff8165c5f5 0000000000000000
[ ]  ffff880236843c18 ffffffff81093d8c 0000000000000000 0000000000000000
[ ]  ffffffff81ccd1a0 ffffffff810ca951 0000000000000000 ffff880236843c28
[ ] Call Trace:
[ ]  [<ffffffff8165c5f5>] dump_stack+0x4e/0x7a
[ ]  [<ffffffff81093d8c>] warn_slowpath_common+0x8c/0xc0
[ ]  [<ffffffff810ca951>] ? sched_clock_tick+0x1/0xa0
[ ]  [<ffffffff81093dda>] warn_slowpath_null+0x1a/0x20
[ ]  [<ffffffff8110b72d>] smp_call_function_many+0xad/0x300
[ ]  [<ffffffff8104f200>] ? arch_unregister_cpu+0x30/0x30
[ ]  [<ffffffff8104f200>] ? arch_unregister_cpu+0x30/0x30
[ ]  [<ffffffff810ca951>] ? sched_clock_tick+0x1/0xa0
[ ]  [<ffffffff8110ba96>] smp_call_function+0x46/0x80
[ ]  [<ffffffff8104f200>] ? arch_unregister_cpu+0x30/0x30
[ ]  [<ffffffff8110bb3c>] on_each_cpu+0x3c/0xa0
[ ]  [<ffffffff810ca950>] ? sched_clock_idle_sleep_event+0x20/0x20
[ ]  [<ffffffff810ca951>] ? sched_clock_tick+0x1/0xa0
[ ]  [<ffffffff8104f964>] text_poke_bp+0x64/0xd0
[ ]  [<ffffffff810ca950>] ? sched_clock_idle_sleep_event+0x20/0x20
[ ]  [<ffffffff8104ccde>] arch_jump_label_transform+0xae/0x130
[ ]  [<ffffffff8115a3cf>] __jump_label_update+0x5f/0x80
[ ]  [<ffffffff8115a48d>] jump_label_update+0x9d/0xb0
[ ]  [<ffffffff8115aa6d>] static_key_slow_inc+0x9d/0xb0
[ ]  [<ffffffff810ca775>] clear_sched_clock_stable+0x15/0x20
[ ]  [<ffffffff810503b3>] mark_tsc_unstable+0x23/0x70
[ ]  [<ffffffff810772cb>] check_tsc_sync_source+0x14b/0x150
[ ]  [<ffffffff81076612>] native_cpu_up+0x3a2/0x890
[ ]  [<ffffffff810941cb>] _cpu_up+0xdb/0x160
[ ]  [<ffffffff810942c9>] cpu_up+0x79/0x90
[ ]  [<ffffffff81d0af6b>] smp_init+0x60/0x8c
[ ]  [<ffffffff81cebf42>] kernel_init_freeable+0x8c/0x197
[ ]  [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ]  [<ffffffff8164e32e>] kernel_init+0xe/0x130
[ ]  [<ffffffff8166beec>] ret_from_fork+0x7c/0xb0
[ ]  [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ] ---[ end trace 6ff1df5620c49d26 ]---
[ ] tsc: Marking TSC unstable due to check_tsc_sync_source failed

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-v55fgqj3nnyqnngmvuu8ep6h@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13 15:13:15 +01:00
..
auto_group.c sched/autogroup: Fix race with task_groups list 2013-05-28 09:40:22 +02:00
auto_group.h Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled" 2012-12-11 10:23:45 +01:00
clock.c sched/clock: Fix up clear_sched_clock_stable() 2014-01-13 15:13:15 +01:00
completion.c sched: Move completion code from core.c to completion.c 2013-11-06 07:49:19 +01:00
core.c sched: Reduce trigger_load_balance() parameters 2014-01-13 13:47:26 +01:00
cpuacct.c cgroup: pass around cgroup_subsys_state instead of cgroup in file methods 2013-08-08 20:11:24 -04:00
cpuacct.h sched/cpuacct: Initialize root cpuacct earlier 2013-04-10 13:54:20 +02:00
cpudeadline.c sched/deadline: speed up SCHED_DEADLINE pushes with a push-heap 2014-01-13 13:46:46 +01:00
cpudeadline.h sched/deadline: speed up SCHED_DEADLINE pushes with a push-heap 2014-01-13 13:46:46 +01:00
cpupri.c sched: Fix some kernel-doc warnings 2013-07-18 09:58:21 +02:00
cpupri.h
cputime.c Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-09-05 12:36:46 -07:00
deadline.c sched/deadline: Remove the sysctl_sched_dl knobs 2014-01-13 13:47:23 +01:00
debug.c sched/clock, x86: Use a static_key for sched_clock_stable 2014-01-13 15:13:13 +01:00
fair.c sched: Factor out the on_null_domain() checks in trigger_load_balance() 2014-01-13 13:47:35 +01:00
features.h sched/numa: Resist moving tasks towards nodes with fewer hinting faults 2013-10-09 12:40:27 +02:00
idle_task.c sched/numa: Introduce migrate_swap() 2013-10-09 12:40:46 +02:00
Makefile sched/deadline: speed up SCHED_DEADLINE pushes with a push-heap 2014-01-13 13:46:46 +01:00
proc.c sched: Change get_rq_runnable_load() to static and inline 2013-06-27 10:07:44 +02:00
rt.c sched/deadline: Add SCHED_DEADLINE SMP-related data structures & logic 2014-01-13 13:41:07 +01:00
sched.h sched: Reduce trigger_load_balance() parameters 2014-01-13 13:47:26 +01:00
stats.c fix a leak in /proc/schedstats 2013-04-29 15:41:45 -04:00
stats.h sched: Micro-optimize by dropping unnecessary task_rq() calls 2013-09-25 13:51:06 +02:00
stop_task.c sched/deadline: Add SCHED_DEADLINE structures & implementation 2014-01-13 13:41:06 +01:00
wait.c sched: Move wait code from core.c to wait.c 2013-11-06 07:49:18 +01:00