Steven Rostedt
e59494f441
ftrace: fix 4d3702b6 (post-v2.6.26): WARNING: at kernel/lockdep.c:2731 check_flags (ftrace)
...
On Wed, 16 Jul 2008, Vegard Nossum wrote:
> When booting 4d3702b6#30
> [<c015c349>] warn_on_slowpath+0x59/0xb0
> [<c01276c6>] ? ftrace_call+0x5/0x8
> [<c012d800>] ? native_read_tsc+0x0/0x20
> [<c0158de2>] ? sub_preempt_count+0x12/0xf0
> [<c01814eb>] ? trace_hardirqs_off+0xb/0x10
> [<c0182fbc>] ? __lock_acquire+0x2cc/0x1120
> [<c01814eb>] ? trace_hardirqs_off+0xb/0x10
> [<c01276af>] ? mcount_call+0x5/0xa
> [<c017ff53>] check_flags+0x123/0x160
> [<c0183e61>] lock_acquire+0x51/0xd0
> [<c01276c6>] ? ftrace_call+0x5/0x8
> [<c0613d4f>] _spin_lock_irqsave+0x5f/0xa0
> [<c01a8d45>] ? ftrace_record_ip+0xf5/0x220
> [<c02d5413>] ? debug_locks_off+0x3/0x50
> [<c01a8d45>] ftrace_record_ip+0xf5/0x220
> [<c01276af>] mcount_call+0x5/0xa
> [<c02d5418>] ? debug_locks_off+0x8/0x50
> [<c017ff27>] check_flags+0xf7/0x160
> [<c0183e61>] lock_acquire+0x51/0xd0
> [<c01276c6>] ? ftrace_call+0x5/0x8
> [<c0613d4f>] _spin_lock_irqsave+0x5f/0xa0
> [<c01affcd>] ? wakeup_tracer_call+0x6d/0xf0
> [<c01625e2>] ? _local_bh_enable+0x62/0xb0
> [<c0158ddd>] ? sub_preempt_count+0xd/0xf0
> [<c01affcd>] wakeup_tracer_call+0x6d/0xf0
> [<c0162724>] ? __do_softirq+0xf4/0x110
> [<c01afff1>] ? wakeup_tracer_call+0x91/0xf0
> [<c01276c6>] ftrace_call+0x5/0x8
> [<c0162724>] ? __do_softirq+0xf4/0x110
> [<c0158de2>] ? sub_preempt_count+0x12/0xf0
> [<c01625e2>] _local_bh_enable+0x62/0xb0
> [<c0162724>] __do_softirq+0xf4/0x110
> [<c01627ed>] do_softirq+0xad/0xb0
> [<c0162a15>] irq_exit+0xa5/0xb0
> [<c013a506>] smp_apic_timer_interrupt+0x66/0xa0
> [<c02d3fac>] ? trace_hardirqs_off_thunk+0xc/0x10
> [<c0127449>] apic_timer_interrupt+0x2d/0x34
> [<c018007b>] ? find_usage_backwards+0xb/0xf0
> [<c0613a09>] ? _spin_unlock_irqrestore+0x69/0x80
> [<c014ef32>] tg_shares_up+0x132/0x1d0
> [<c014d2a2>] walk_tg_tree+0x62/0xa0
> [<c014ee00>] ? tg_shares_up+0x0/0x1d0
> [<c014a860>] ? tg_nop+0x0/0x10
> [<c015499d>] update_shares+0x5d/0x80
> [<c0154a2f>] try_to_wake_up+0x6f/0x280
> [<c01a8b90>] ? __ftrace_modify_code+0x0/0xc0
> [<c01a8b90>] ? __ftrace_modify_code+0x0/0xc0
> [<c0154c94>] wake_up_process+0x14/0x20
> [<c01725f6>] kthread_create+0x66/0xb0
> [<c0195400>] ? do_stop+0x0/0x200
> [<c0195320>] ? __stop_machine_run+0x30/0xb0
> [<c0195340>] __stop_machine_run+0x50/0xb0
> [<c0195400>] ? do_stop+0x0/0x200
> [<c01a8b90>] ? __ftrace_modify_code+0x0/0xc0
> [<c061242d>] ? mutex_unlock+0xd/0x10
> [<c01953cc>] stop_machine_run+0x2c/0x60
> [<c01a94d3>] unregister_ftrace_function+0x103/0x180
> [<c01b0517>] stop_wakeup_tracer+0x17/0x60
> [<c01b056f>] wakeup_tracer_ctrl_update+0xf/0x30
> [<c01ab8d5>] trace_selftest_startup_wakeup+0xb5/0x130
> [<c01ab950>] ? trace_wakeup_test_thread+0x0/0x70
> [<c01aadf5>] register_tracer+0x135/0x1b0
> [<c0877d02>] init_wakeup_tracer+0xd/0xf
> [<c085d437>] kernel_init+0x1a9/0x2ce
> [<c061397b>] ? _spin_unlock_irq+0x3b/0x60
> [<c02d3f9c>] ? trace_hardirqs_on_thunk+0xc/0x10
> [<c0877cf5>] ? init_wakeup_tracer+0x0/0xf
> [<c0182646>] ? trace_hardirqs_on_caller+0x126/0x180
> [<c02d3f9c>] ? trace_hardirqs_on_thunk+0xc/0x10
> [<c01269c8>] ? restore_nocheck_notrace+0x0/0xe
> [<c085d28e>] ? kernel_init+0x0/0x2ce
> [<c085d28e>] ? kernel_init+0x0/0x2ce
> [<c01275fb>] kernel_thread_helper+0x7/0x10
> =======================
> ---[ end trace a7919e7f17c0a725 ]---
> irq event stamp: 579530
> hardirqs last enabled at (579528): [<c01826ab>] trace_hardirqs_on+0xb/0x10
> hardirqs last disabled at (579529): [<c01814eb>] trace_hardirqs_off+0xb/0x10
> softirqs last enabled at (579530): [<c0162724>] __do_softirq+0xf4/0x110
> softirqs last disabled at (579517): [<c01627ed>] do_softirq+0xad/0xb0
> irq event stamp: 579530
> hardirqs last enabled at (579528): [<c01826ab>] trace_hardirqs_on+0xb/0x10
> hardirqs last disabled at (579529): [<c01814eb>] trace_hardirqs_off+0xb/0x10
> softirqs last enabled at (579530): [<c0162724>] __do_softirq+0xf4/0x110
> softirqs last disabled at (579517): [<c01627ed>] do_softirq+0xad/0xb0
> PASSED
>
> Incidentally, the kernel also hung while I was typing in this report.
Things get weird between lockdep and ftrace because ftrace can be called
within lockdep internal code (via the mcount pointer) and lockdep can be
called with ftrace (via spin_locks).
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-18 13:47:15 +02:00
Steven Rostedt
ad591240ce
ftrace: start wakeup tracing after setting function tracer
...
Enabling the wakeup tracer before enabling the function tracing causes
some strange results due to the dynamic enabling of the functions.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-11 15:49:20 +02:00
Steven Rostedt
7e18d8e701
ftrace: add function tracing to wake up tracing
...
This patch adds function tracing to the functions that are called
on the CPU of the task being traced.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: pq@iki.fi
Cc: proski@gnu.org
Cc: sandmann@redhat.com
Cc: a.p.zijlstra@chello.nl
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-26 22:51:22 +02:00
Mathieu Desnoyers
5b82a1b08a
Port ftrace to markers
...
Porting ftrace to the marker infrastructure.
Don't need to chain to the wakeup tracer from the sched tracer, because markers
support multiple probes connected.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 22:29:25 +02:00
Steven Rostedt
4fe8c3048c
ftrace: printk and trace irqsoff and wakeups
...
printk called from wakeup critical timings and irqs off can
cause deadlocks since printk might do a wakeup itself. If the
call to printk happens with the runqueue lock held, it can
deadlock.
This patch protects the printk from being called in trace irqs off
with a test to see if the runqueue for the current CPU is locked.
If it is locked, the printk is skipped.
The wakeup always holds the runqueue lock, so the printk is
simply removed.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 21:13:02 +02:00
Ingo Molnar
8ac0fca4cc
ftrace: sched tracer fix
...
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 21:04:28 +02:00
Ingo Molnar
57422797dc
ftrace: add wakeup events to sched tracer
...
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 21:04:06 +02:00
Ingo Molnar
e309b41dd6
ftrace: remove notrace
...
now that we have a kbuild method for notrace, no need to pollute the
C code with the annotations.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:58:28 +02:00
Steven Rostedt
6fb44b717c
ftrace: add trace_function api for other tracers to use
...
A new check was added in the ftrace function that wont trace if the CPU
trace buffer is disabled. Unfortunately, other tracers used ftrace() to
write to the buffer after they disabled it. The new disable check makes
these calls into a nop.
This patch changes the __ftrace that is called without the check into a
new api for the other tracers to use, called "trace_function". The other
tracers use this interface instead when the trace CPU buffer is already
disabled.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:55:55 +02:00
Ingo Molnar
750ed1a407
ftrace: timestamp syncing, prepare
...
rename and uninline now() to ftrace_now().
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:42:31 +02:00
Ingo Molnar
c7aafc5497
ftrace: cleanups
...
factor out code and clean it up.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:40:46 +02:00
Steven Rostedt
60a11774b3
ftrace: add self-tests
...
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:40:36 +02:00
Steven Rostedt
352ad25aa4
ftrace: tracer for scheduler wakeup latency
...
This patch adds the tracer that tracks the wakeup latency of the
highest priority waking task.
"wakeup" is added to /debugfs/tracing/available_tracers
Also added to /debugfs/tracing
tracing_max_latency
holds the current max latency for the wakeup
wakeup_thresh
if set to other than zero, a log will be recorded
for every wakeup that takes longer than the number
entered in here (usecs for all counters)
(deletes previous trace)
Examples:
(with ftrace_enabled = 0)
============
preemption latency trace v1.1.5 on 2.6.24-rc8
Signed-off-by: Ingo Molnar <mingo@elte.hu>
--------------------------------------------------------------------
latency: 26 us, #2/2, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
-----------------
| task: migration/0-3 (uid:0 nice:-5 policy:1 rt_prio:99)
-----------------
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| /
||||| delay
cmd pid ||||| time | caller
\ / ||||| \ | /
quilt-8551 0d..3 0us+: wake_up_process+0x15/0x17 <ffffffff80233e80> (sched_exec+0xc9/0x100 <ffffffff80235343>)
quilt-8551 0d..4 26us : sched_switch_callback+0x73/0x81 <ffffffff80338d2f> (schedule+0x483/0x6d5 <ffffffff8048b3ee>)
vim:ft=help
============
(with ftrace_enabled = 1)
============
preemption latency trace v1.1.5 on 2.6.24-rc8
--------------------------------------------------------------------
latency: 36 us, #45/45, CPU#0 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
-----------------
| task: migration/1-5 (uid:0 nice:-5 policy:1 rt_prio:99)
-----------------
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| /
||||| delay
cmd pid ||||| time | caller
\ / ||||| \ | /
bash-10653 1d..3 0us : wake_up_process+0x15/0x17 <ffffffff80233e80> (sched_exec+0xc9/0x100 <ffffffff80235343>)
bash-10653 1d..3 1us : try_to_wake_up+0x271/0x2e7 <ffffffff80233dcf> (sub_preempt_count+0xc/0x7a <ffffffff8023309e>)
bash-10653 1d..2 2us : try_to_wake_up+0x296/0x2e7 <ffffffff80233df4> (update_rq_clock+0x9/0x20 <ffffffff802303f3>)
bash-10653 1d..2 2us : update_rq_clock+0x1e/0x20 <ffffffff80230408> (__update_rq_clock+0xc/0x90 <ffffffff80230366>)
bash-10653 1d..2 3us : __update_rq_clock+0x1b/0x90 <ffffffff80230375> (sched_clock+0x9/0x29 <ffffffff80214529>)
bash-10653 1d..2 4us : try_to_wake_up+0x2a6/0x2e7 <ffffffff80233e04> (activate_task+0xc/0x3f <ffffffff8022ffca>)
bash-10653 1d..2 4us : activate_task+0x2d/0x3f <ffffffff8022ffeb> (enqueue_task+0xe/0x66 <ffffffff8022ff66>)
bash-10653 1d..2 5us : enqueue_task+0x5b/0x66 <ffffffff8022ffb3> (enqueue_task_rt+0x9/0x3c <ffffffff80233351>)
bash-10653 1d..2 6us : try_to_wake_up+0x2ba/0x2e7 <ffffffff80233e18> (check_preempt_wakeup+0x12/0x99 <ffffffff80234f84>)
[...]
bash-10653 1d..5 33us : tracing_record_cmdline+0xcf/0xd4 <ffffffff80338aad> (_spin_unlock+0x9/0x33 <ffffffff8048d3ec>)
bash-10653 1d..5 34us : _spin_unlock+0x19/0x33 <ffffffff8048d3fc> (sub_preempt_count+0xc/0x7a <ffffffff8023309e>)
bash-10653 1d..4 35us : wakeup_sched_switch+0x65/0x2ff <ffffffff80339f66> (_spin_lock_irqsave+0xc/0xa9 <ffffffff8048d08b>)
bash-10653 1d..4 35us : _spin_lock_irqsave+0x19/0xa9 <ffffffff8048d098> (add_preempt_count+0xe/0x77 <ffffffff8023311a>)
bash-10653 1d..4 36us : sched_switch_callback+0x73/0x81 <ffffffff80338d2f> (schedule+0x483/0x6d5 <ffffffff8048b3ee>)
vim:ft=help
============
The [...] was added here to not waste your email box space.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:32:36 +02:00
