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Commit a82274151af "tracing: Protect ftrace_trace_arrays list in trace_events.c"
added taking the trace_types_lock mutex in trace_events.c as there were
several locations that needed it for protection. Unfortunately, it also
encapsulated a call to tracing_reset_all_online_cpus() which also takes
the trace_types_lock, causing a deadlock.
This happens when a module has tracepoints and has been traced. When the
module is removed, the trace events module notifier will grab the
trace_types_lock, do a bunch of clean ups, and also clears the buffer
by calling tracing_reset_all_online_cpus. This doesn't happen often
which explains why it wasn't caught right away.
Commit a82274151af was marked for stable, which means this must be
sent to stable too.
Link: http://lkml.kernel.org/r/51EEC646.7070306@broadcom.com
Reported-by: Arend van Spril <arend@broadcom.com>
Tested-by: Arend van Spriel <arend@broadcom.com>
Cc: Alexander Z Lam <azl@google.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Change where ftrace is disabled and re-enabled during system
suspend/resume to allow tracing of device driver pm callbacks.
Ftrace will now be turned off when suspend reaches
disable_nonboot_cpus() instead of at the very beginning of system
suspend.
Ftrace was disabled during suspend/resume back in 2008 by
Steven Rostedt as he discovered there was a conflict in the
enable_nonboot_cpus() call (see commit f42ac38 "ftrace: disable
tracing for suspend to ram"). This change preserves his fix by
disabling ftrace, but only at the function where it is known
to cause problems.
The new change allows tracing of the device level code for better
debug.
[rjw: Changelog]
Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Fengguang reported the following warning when optimistic
spinning is disabled (ie: make allnoconfig):
kernel/mutex.c:599:1: warning: label 'done' defined but not used
Remove the 'done' label altogether.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/urgent
Pull nohz fixes from Frederic Weisbecker.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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cpu is not used after commit 5b8621a68fdcd2baf1d3b413726f913a5254d46a
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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If the user enables CONFIG_NO_HZ_FULL and runs the kernel on a machine
with an unstable TSC, it will produce a WARN_ON dump as well as taint
the kernel. This is a bit extreme for a kernel that just enables a
feature but doesn't use it.
The warning should only happen if the user tries to use the feature by
either adding nohz_full to the kernel command line, or by enabling
CONFIG_NO_HZ_FULL_ALL that makes nohz used on all CPUs at boot up. Note,
this second feature should not (yet) be used by distros or anyone that
doesn't care if NO_HZ is used or not.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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If the @fn call work_on_cpu() again, the lockdep will complain:
> [ INFO: possible recursive locking detected ]
> 3.11.0-rc1-lockdep-fix-a #6 Not tainted
> ---------------------------------------------
> kworker/0:1/142 is trying to acquire lock:
> ((&wfc.work)){+.+.+.}, at: [<ffffffff81077100>] flush_work+0x0/0xb0
>
> but task is already holding lock:
> ((&wfc.work)){+.+.+.}, at: [<ffffffff81075dd9>] process_one_work+0x169/0x610
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock((&wfc.work));
> lock((&wfc.work));
>
> *** DEADLOCK ***
It is false-positive lockdep report. In this sutiation,
the two "wfc"s of the two work_on_cpu() are different,
they are both on stack. flush_work() can't be deadlock.
To fix this, we need to avoid the lockdep checking in this case,
thus we instroduce a internal __flush_work() which skip the lockdep.
tj: Minor comment adjustment.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reported-by: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Reported-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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If a ftrace ops is registered with the SAVE_REGS flag set, and there's
already a ops registered to one of its functions but without the
SAVE_REGS flag, there's a small race window where the SAVE_REGS ops gets
added to the list of callbacks to call for that function before the
callback trampoline gets set to save the regs.
The problem is, the function is not currently saving regs, which opens
a small race window where the ops that is expecting regs to be passed
to it, wont. This can cause a crash if the callback were to reference
the regs, as the SAVE_REGS guarantees that regs will be set.
To fix this, we add a check in the loop case where it checks if the ops
has the SAVE_REGS flag set, and if so, it will ignore it if regs is
not set.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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After the previous changes trace_array_cpu->trace_cpu and
trace_array->trace_cpu becomes write-only. Remove these members
and kill "struct trace_cpu" as well.
As a side effect this also removes memset(per_cpu_memory, 0).
It was not needed, alloc_percpu() returns zero-filled memory.
Link: http://lkml.kernel.org/r/20130723152613.GA23741@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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tracing_open() and tracing_snapshot_open() are racy, the memory
inode->i_private points to can be already freed.
Convert these last users of "inode->i_private == trace_cpu" to
use "i_private = trace_array" and rely on tracing_get_cpu().
v2: incorporate the fix from Steven, tracing_release() must not
blindly dereference file->private_data unless we know that
the file was opened for reading.
Link: http://lkml.kernel.org/r/20130723152610.GA23737@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.
1. Change its last user, tracing_entries_fops, to use
tracing_*_generic_tr() instead.
2. Change debugfs_create_file("buffer_size_kb", data) callers
to pass "data = tr".
3. Change tracing_entries_read() and tracing_entries_write() to
use tracing_get_cpu().
4. Kill the no longer used tracing_open_generic_tc() and
tracing_release_generic_tc().
Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.
1. Change one of its users, tracing_stats_fops, to use
tracing_*_generic_tr() instead.
2. Change trace_create_cpu_file("stats", data) to pass "data = tr".
3. Change tracing_stats_read() to use tracing_get_cpu().
Link: http://lkml.kernel.org/r/20130723152603.GA23727@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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tracing_buffers_open() is racy, the memory inode->i_private points
to can be already freed.
Change debugfs_create_file("trace_pipe_raw", data) caller to pass
"data = tr", tracing_buffers_open() can use tracing_get_cpu().
Change debugfs_create_file("snapshot_raw_fops", data) caller too,
this file uses tracing_buffers_open/release.
Link: http://lkml.kernel.org/r/20130723152600.GA23720@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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tracing_open_pipe() is racy, the memory inode->i_private points to
can be already freed.
Change debugfs_create_file("trace_pipe", data) callers to to pass
"data = tr", tracing_open_pipe() can use tracing_get_cpu().
Link: http://lkml.kernel.org/r/20130723152557.GA23717@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Every "file_operations" used by tracing_init_debugfs_percpu is buggy.
f_op->open/etc does:
1. struct trace_cpu *tc = inode->i_private;
struct trace_array *tr = tc->tr;
2. trace_array_get(tr) or fail;
3. do_something(tc);
But tc (and tr) can be already freed before trace_array_get() is called.
And it doesn't matter whether this file is per-cpu or it was created by
init_tracer_debugfs(), free_percpu() or kfree() are equally bad.
Note that even 1. is not safe, the freed memory can be unmapped. But even
if it was safe trace_array_get() can wrongly succeed if we also race with
the next new_instance_create() which can re-allocate the same tr, or tc
was overwritten and ->tr points to the valid tr. In this case 3. uses the
freed/reused memory.
Add the new trivial helper, trace_create_cpu_file() which simply calls
trace_create_file() and encodes "cpu" in "struct inode". Another helper,
tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS.
The patch abuses ->i_cdev to encode the number, it is never used unless
the file is S_ISCHR(). But we could use something else, say, i_bytes or
even ->d_fsdata. In any case this hack is hidden inside these 2 helpers,
it would be trivial to change them if needed.
This patch only changes tracing_init_debugfs_percpu() to use the new
trace_create_cpu_file(), the next patches will change file_operations.
Note: tracing_get_cpu(inode) is always safe but you can't trust the
result unless trace_array_get() was called, without trace_types_lock
which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS.
Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup changes from Tejun Heo:
"This contains two patches, both of which aren't fixes per-se but I
think it'd be better to fast-track them.
One removes bcache_subsys_id which was added without proper review
through the block tree. Fortunately, bcache cgroup code is
unconditionally disabled, so this was never exposed to userland. The
cgroup subsys_id is removed. Kent will remove the affected (disabled)
code through bcache branch.
The other simplifies task_group_path_from_hierarchy(). The function
doesn't currently have in-kernel users but there are external code and
development going on dependent on the function and making the function
available for 3.11 would make things go smoother"
* 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: replace task_cgroup_path_from_hierarchy() with task_cgroup_path()
cgroup: remove bcache_subsys_id which got added stealthily
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Fix __wait_on_atomic_t() so that it calls the action func if the counter != 0
rather than if the counter is 0 so as to be analogous to __wait_on_bit().
Thanks to Yacine who found this by visual inspection.
This will affect FS-Cache in that it will could fail to sleep correctly when
trying to clean up after a netfs cookie is withdrawn.
Reported-by: Yacine Belkadi <yacine.belkadi.1@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Smart wake-affine is using node-size as the factor currently, but the overhead
of the mask operation is high.
Thus, this patch introduce the 'sd_llc_size' percpu variable, which will record
the highest cache-share domain size, and make it to be the new factor, in order
to reduce the overhead and make it more reasonable.
Tested-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/51D5008E.6030102@linux.vnet.ibm.com
[ Tidied up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The wake-affine scheduler feature is currently always trying to pull
the wakee close to the waker. In theory this should be beneficial if
the waker's CPU caches hot data for the wakee, and it's also beneficial
in the extreme ping-pong high context switch rate case.
Testing shows it can benefit hackbench up to 15%.
However, the feature is somewhat blind, from which some workloads
such as pgbench suffer. It's also time-consuming algorithmically.
Testing shows it can damage pgbench up to 50% - far more than the
benefit it brings in the best case.
So wake-affine should be smarter and it should realize when to
stop its thankless effort at trying to find a suitable CPU to wake on.
This patch introduces 'wakee_flips', which will be increased each
time the task flips (switches) its wakee target.
So a high 'wakee_flips' value means the task has more than one
wakee, and the bigger the number, the higher the wakeup frequency.
Now when making the decision on whether to pull or not, pay attention to
the wakee with a high 'wakee_flips', pulling such a task may benefit
the wakee. Also imply that the waker will face cruel competition later,
it could be very cruel or very fast depends on the story behind
'wakee_flips', waker therefore suffers.
Furthermore, if waker also has a high 'wakee_flips', that implies that
multiple tasks rely on it, then waker's higher latency will damage all
of them, so pulling wakee seems to be a bad deal.
Thus, when 'waker->wakee_flips / wakee->wakee_flips' becomes
higher and higher, the cost of pulling seems to be worse and worse.
The patch therefore helps the wake-affine feature to stop its pulling
work when:
wakee->wakee_flips > factor &&
waker->wakee_flips > (factor * wakee->wakee_flips)
The 'factor' here is the number of CPUs in the current CPU's NUMA node,
so a bigger node will lead to more pulling since the trial becomes more
severe.
After applying the patch, pgbench shows up to 40% improvements and no regressions.
Tested with 12 cpu x86 server and tip 3.10.0-rc7.
The percentages in the final column highlight the areas with the biggest wins,
all other areas improved as well:
pgbench base smart
| db_size | clients | tps | | tps |
+---------+---------+-------+ +-------+
| 22 MB | 1 | 10598 | | 10796 |
| 22 MB | 2 | 21257 | | 21336 |
| 22 MB | 4 | 41386 | | 41622 |
| 22 MB | 8 | 51253 | | 57932 |
| 22 MB | 12 | 48570 | | 54000 |
| 22 MB | 16 | 46748 | | 55982 | +19.75%
| 22 MB | 24 | 44346 | | 55847 | +25.93%
| 22 MB | 32 | 43460 | | 54614 | +25.66%
| 7484 MB | 1 | 8951 | | 9193 |
| 7484 MB | 2 | 19233 | | 19240 |
| 7484 MB | 4 | 37239 | | 37302 |
| 7484 MB | 8 | 46087 | | 50018 |
| 7484 MB | 12 | 42054 | | 48763 |
| 7484 MB | 16 | 40765 | | 51633 | +26.66%
| 7484 MB | 24 | 37651 | | 52377 | +39.11%
| 7484 MB | 32 | 37056 | | 51108 | +37.92%
| 15 GB | 1 | 8845 | | 9104 |
| 15 GB | 2 | 19094 | | 19162 |
| 15 GB | 4 | 36979 | | 36983 |
| 15 GB | 8 | 46087 | | 49977 |
| 15 GB | 12 | 41901 | | 48591 |
| 15 GB | 16 | 40147 | | 50651 | +26.16%
| 15 GB | 24 | 37250 | | 52365 | +40.58%
| 15 GB | 32 | 36470 | | 50015 | +37.14%
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51D50057.9000809@linux.vnet.ibm.com
[ Improved the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The bad thing about update_h_load(), which computes hierarchical load
factor for task groups, is that it is called for each task group in the
system before every load balancer run, and since rebalance can be
triggered very often, this function can eat really a lot of cpu time if
there are many cpu cgroups in the system.
Although the situation was improved significantly by commit a35b646
('sched, cgroup: Reduce rq->lock hold times for large cgroup
hierarchies'), the problem still can arise under some kinds of loads,
e.g. when cpus are switching from idle to busy and back very frequently.
For instance, when I start 1000 of processes that wake up every
millisecond on my 8 cpus host, 'top' and 'perf top' show:
Cpu(s): 17.8%us, 24.3%sy, 0.0%ni, 57.9%id, 0.0%wa, 0.0%hi, 0.0%si
Events: 243K cycles
7.57% [kernel] [k] __schedule
7.08% [kernel] [k] timerqueue_add
6.13% libc-2.12.so [.] usleep
Then if I create 10000 *idle* cpu cgroups (no processes in them), cpu
usage increases significantly although the 'wakers' are still executing
in the root cpu cgroup:
Cpu(s): 19.1%us, 48.7%sy, 0.0%ni, 31.6%id, 0.0%wa, 0.0%hi, 0.7%si
Events: 230K cycles
24.56% [kernel] [k] tg_load_down
5.76% [kernel] [k] __schedule
This happens because this particular kind of load triggers 'new idle'
rebalance very frequently, which requires calling update_h_load(),
which, in turn, calls tg_load_down() for every *idle* cpu cgroup even
though it is absolutely useless, because idle cpu cgroups have no tasks
to pull.
This patch tries to improve the situation by making h_load calculation
proceed only when h_load is really necessary. To achieve this, it
substitutes update_h_load() with update_cfs_rq_h_load(), which computes
h_load only for a given cfs_rq and all its ascendants, and makes the
load balancer call this function whenever it considers if a task should
be pulled, i.e. it moves h_load calculations directly to task_h_load().
For h_load of the same cfs_rq not to be updated multiple times (in case
several tasks in the same cgroup are considered during the same balance
run), the patch keeps the time of the last h_load update for each cfs_rq
and breaks calculation when it finds h_load to be uptodate.
The benefit of it is that h_load is computed only for those cfs_rq's,
which really need it, in particular all idle task groups are skipped.
Although this, in fact, moves h_load calculation under rq lock, it
should not affect latency much, because the amount of work done under rq
lock while trying to pull tasks is limited by sched_nr_migrate.
After the patch applied with the setup described above (1000 wakers in
the root cgroup and 10000 idle cgroups), I get:
Cpu(s): 16.9%us, 24.8%sy, 0.0%ni, 58.4%id, 0.0%wa, 0.0%hi, 0.0%si
Events: 242K cycles
7.57% [kernel] [k] __schedule
6.70% [kernel] [k] timerqueue_add
5.93% libc-2.12.so [.] usleep
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1373896159-1278-1-git-send-email-vdavydov@parallels.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Due to a discussion with Adrian I had a good look at the perf_event_type record
layout and found the documentation to be somewhat unclear.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130716150907.GL23818@dyad.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Upon entering the slowpath, we immediately attempt to acquire
the lock by checking if it is already unlocked. If we are lucky
enough that this is the case, then we don't need to deal with
any waiter related logic.
Furthermore any checks for an empty wait_list are unnecessary as
we already know that count is non-negative and hence no one is
waiting for the lock.
Move the count check and xchg calls to be done before any
waiters are setup - including waiter debugging. Upon failure to
acquire the lock, the xchg sets the counter to 0, instead of -1
as it was originally. This can be done here since we set it back
to -1 right at the beginning of the loop so other waiters are
woken up when the lock is released.
When tested on a 8-socket (80 core) system against a vanilla
3.10-rc1 kernel, this patch provides some small performance
benefits (+2-6%). While it could be considered in the noise
level, the average percentages were stable across multiple runs
and no performance regressions were seen. Two big winners, for
small amounts of users (10-100), were the short and compute
workloads had a +19.36% and +%15.76% in jobs per minute.
Also change some break statements to 'goto slowpath', which IMO
makes a little more intuitive to read.
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1372450398.2106.1.camel@buesod1.americas.hpqcorp.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge in Linux 3.11-rc2 before moving on with new work.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In fd4363fff3d96 ("x86: Introduce int3 (breakpoint)-based
instruction patching"), the mechanism that was introduced for
notifying alternatives code from int3 exception handler that and
exception occured was die_notifier.
This is however problematic, as early code might be using jump
labels even before the notifier registration has been performed,
which will then lead to an oops due to unhandled exception. One
of such occurences has been encountered by Fengguang:
int3: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.11.0-rc1-01429-g04bf576 #8
task: ffff88000da1b040 ti: ffff88000da1c000 task.ti: ffff88000da1c000
RIP: 0010:[<ffffffff811098cc>] [<ffffffff811098cc>] ttwu_do_wakeup+0x28/0x225
RSP: 0000:ffff88000dd03f10 EFLAGS: 00000006
RAX: 0000000000000000 RBX: ffff88000dd12940 RCX: ffffffff81769c40
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffff88000dd03f28 R08: ffffffff8176a8c0 R09: 0000000000000002
R10: ffffffff810ff484 R11: ffff88000dd129e8 R12: ffff88000dbc90c0
R13: ffff88000dbc90c0 R14: ffff88000da1dfd8 R15: ffff88000da1dfd8
FS: 0000000000000000(0000) GS:ffff88000dd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000ffffffff CR3: 0000000001c88000 CR4: 00000000000006e0
Stack:
ffff88000dd12940 ffff88000dbc90c0 ffff88000da1dfd8 ffff88000dd03f48
ffffffff81109e2b ffff88000dd12940 0000000000000000 ffff88000dd03f68
ffffffff81109e9e 0000000000000000 0000000000012940 ffff88000dd03f98
Call Trace:
<IRQ>
[<ffffffff81109e2b>] ttwu_do_activate.constprop.56+0x6d/0x79
[<ffffffff81109e9e>] sched_ttwu_pending+0x67/0x84
[<ffffffff8110c845>] scheduler_ipi+0x15a/0x2b0
[<ffffffff8104dfb4>] smp_reschedule_interrupt+0x38/0x41
[<ffffffff8173bf5d>] reschedule_interrupt+0x6d/0x80
<EOI>
[<ffffffff810ff484>] ? __atomic_notifier_call_chain+0x5/0xc1
[<ffffffff8105cc30>] ? native_safe_halt+0xd/0x16
[<ffffffff81015f10>] default_idle+0x147/0x282
[<ffffffff81017026>] arch_cpu_idle+0x3d/0x5d
[<ffffffff81127d6a>] cpu_idle_loop+0x46d/0x5db
[<ffffffff81127f5c>] cpu_startup_entry+0x84/0x84
[<ffffffff8104f4f8>] start_secondary+0x3c8/0x3d5
[...]
Fix this by directly calling poke_int3_handler() from the int3
exception handler (analogically to what ftrace has been doing
already), instead of relying on notifier, registration of which
might not have yet been finalized by the time of the first trap.
Reported-and-tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1307231007490.14024@pobox.suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes and cleanups from Steven Rostedt:
"This contains fixes, optimizations and some clean ups
Some of the fixes need to go back to 3.10. They are minor, and deal
mostly with incorrect ref counting in accessing event files.
There was a couple of optimizations that should have perf perform a
bit better when accessing trace events.
And some various clean ups. Some of the clean ups are necessary to
help in a fix to a theoretical race between opening a event file and
deleting that event"
* tag 'trace-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open()
tracing: Kill trace_array->waiter
tracing: Do not (ab)use trace_seq in event_id_read()
tracing: Simplify the iteration logic in f_start/f_next
tracing: Add ref_data to function and fgraph tracer structs
tracing: Miscellaneous fixes for trace_array ref counting
tracing: Fix error handling to ensure instances can always be removed
tracing/kprobe: Wait for disabling all running kprobe handlers
tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()
tracing/syscall: Avoid perf_trace_buf_*() if sys_data->perf_events is empty
tracing/function: Avoid perf_trace_buf_*() if event_function.perf_events is empty
tracing: Typo fix on ring buffer comments
tracing: Use trace_seq_puts()/trace_seq_putc() where possible
tracing: Use correct config guard CONFIG_STACK_TRACER
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The expression '(1 << 32)' happens to evaluate as 0 on ARM, but
it evaluates as 1 on xtensa and x86_64. This zeros sched_clock_mask,
and breaks sched_clock().
Set the type of 1 to 'unsigned long long' to get the value we need.
Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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If I explicitly disable the clocksource watchdog in the x86 Kconfig,
the x86 kernel will not compile unless this is properly defined.
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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mutex_can_spin_on_owner() is technically broken in that it would
in theory allow the compiler to load lock->owner twice, seeing a
pointer first time and a NULL pointer the second time.
Linus pointed out that a compiler has to be seriously broken to
not compile this correctly - but nevertheless this change
is correct as it will better document the implementation.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Waiman Long <Waiman.Long@hp.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20130719183101.GA20909@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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cfs_rq is declared twice, fix it.
Also use 'se' instead of '&p->se'.
Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/169201374366727@web6d.yandex.ru
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge in Linux 3.11-rc2, to provide a post-merge-window development base.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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tracing_buffers_open() does trace_array_get() and then it wrongly
inrcements tr->ref again under trace_types_lock. This means that
every caller leaks trace_array:
# cd /sys/kernel/debug/tracing/
# mkdir instances/X
# true < instances/X/per_cpu/cpu0/trace_pipe_raw
# rmdir instances/X
rmdir: failed to remove `instances/X': Device or resource busy
Link: http://lkml.kernel.org/r/20130719153644.GA18899@redhat.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management and ACPI fixes from Rafael Wysocki:
"These are fixes collected over the last week, most importnatly two
cpufreq reverts fixing regressions introduced in 3.10, an autoseelp
fix preventing systems using it from crashing during shutdown and two
ACPI scan fixes related to hotplug.
Specifics:
- Two cpufreq commits from the 3.10 cycle introduced regressions.
The first of them was buggy (it did way much more than it needed to
do) and the second one attempted to fix an issue introduced by the
first one. Fixes from Srivatsa S Bhat revert both.
- If autosleep triggers during system shutdown and the shutdown
callbacks of some device drivers have been called already, it may
crash the system. Fix from Liu Shuo prevents that from happening
by making try_to_suspend() check system_state.
- The ACPI memory hotplug driver doesn't clear its driver_data on
errors which may cause a NULL poiter dereference to happen later.
Fix from Toshi Kani.
- The ACPI namespace scanning code should not try to attach scan
handlers to device objects that have them already, which may
confuse things quite a bit, and it should rescan the whole
namespace branch starting at the given node after receiving a bus
check notify event even if the device at that particular node has
been discovered already. Fixes from Rafael J Wysocki.
- New ACPI video blacklist entry for a system whose initial backlight
setting from the BIOS doesn't make sense. From Lan Tianyu.
- Garbage string output avoindance for ACPI PNP from Liu Shuo.
- Two Kconfig fixes for issues introduced recently in the s3c24xx
cpufreq driver (when moving the driver to drivers/cpufreq) from
Paul Bolle.
- Trivial comment fix in pm_wakeup.h from Chanwoo Choi"
* tag 'pm+acpi-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / video: ignore BIOS initial backlight value for Fujitsu E753
PNP / ACPI: avoid garbage in resource name
cpufreq: Revert commit 2f7021a8 to fix CPU hotplug regression
cpufreq: s3c24xx: fix "depends on ARM_S3C24XX" in Kconfig
cpufreq: s3c24xx: rename CONFIG_CPU_FREQ_S3C24XX_DEBUGFS
PM / Sleep: Fix comment typo in pm_wakeup.h
PM / Sleep: avoid 'autosleep' in shutdown progress
cpufreq: Revert commit a66b2e to fix suspend/resume regression
ACPI / memhotplug: Fix a stale pointer in error path
ACPI / scan: Always call acpi_bus_scan() for bus check notifications
ACPI / scan: Do not try to attach scan handlers to devices having them
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Trivial. trace_array->waiter has no users since 6eaaa5d5
"tracing/core: use appropriate waiting on trace_pipe".
Link: http://lkml.kernel.org/r/20130719142036.GA1594@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Upcoming kprobes patches rely on the int3 code-patching machinery introduced by:
fd4363fff3d9 x86: Introduce int3 (breakpoint)-based instruction patching
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge in a v3.11-rc1-ish branch to go from v3.10 based development
to a v3.11 based one.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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event_id_read() has no reason to kmalloc "struct trace_seq"
(more than PAGE_SIZE!), it can use a small buffer instead.
Note: "if (*ppos) return 0" looks strange and even wrong,
simple_read_from_buffer() handles ppos != 0 case corrrectly.
And it seems that almost every user of trace_seq in this file
should be converted too. Unless you use seq_open(), trace_seq
buys nothing compared to the raw buffer, but it needs a bit
more memory and code.
Link: http://lkml.kernel.org/r/20130718184712.GA4786@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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f_next() looks overcomplicated, and it is not strictly correct
even if this doesn't matter.
Say, FORMAT_FIELD_SEPERATOR should not return NULL (means EOF)
if trace_get_fields() returns an empty list, we should simply
advance to FORMAT_PRINTFMT as we do when we find the end of list.
1. Change f_next() to return "struct list_head *" rather than
"ftrace_event_field *", and change f_show() to do list_entry().
This simplifies the code a bit, only f_show() needs to know
about ftrace_event_field, and f_next() can play with ->prev
directly
2. Change f_next() to not play with ->prev / return inside the
switch() statement. It can simply set node = head/common_head,
the prev-or-advance-to-the-next-magic below does all work.
While at it. f_start() looks overcomplicated too. I don't think
*pos == 0 makes sense as a separate case, just change this code
to do "while" instead of "do/while".
The patch also moves f_start() down, close to f_stop(). This is
purely cosmetic, just to make the locking added by the next patch
more clear/visible.
Link: http://lkml.kernel.org/r/20130718184710.GA4783@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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The selftest for function and function graph tracers are defined as
__init, as they are only executed at boot up. The "tracer" structs
that are associated to those tracers are not setup as __init as they
are used after boot. To stop mismatch warnings, those structures
need to be annotated with __ref_data.
Currently, the tracer structures are defined to __read_mostly, as they
do not really change. But in the future they should be converted to
consts, but that will take a little work because they have a "next"
pointer that gets updated when they are registered. That will have to
wait till the next major release.
Link: http://lkml.kernel.org/r/1373596735.17876.84.camel@gandalf.local.home
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Some error paths did not handle ref counting properly, and some trace files need
ref counting.
Link: http://lkml.kernel.org/r/1374171524-11948-1-git-send-email-azl@google.com
Cc: stable@vger.kernel.org # 3.10
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Remove debugfs directories for tracing instances during creation if an error
occurs causing the trace_array for that instance to not be added to
ftrace_trace_arrays. If the directory continues to exist after the error, it
cannot be removed because the respective trace_array is not in
ftrace_trace_arrays.
Link: http://lkml.kernel.org/r/1373502874-1706-2-git-send-email-azl@google.com
Cc: stable@vger.kernel.org # 3.10
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Wait for disabling all running kprobe handlers when a kprobe
event is disabled, since the caller, trace_remove_event_call()
supposes that a removing event is disabled completely by
disabling the event.
With this change, ftrace can ensure that there is no running
event handlers after disabling it.
Link: http://lkml.kernel.org/r/20130709093526.20138.93100.stgit@mhiramat-M0-7522
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Every perf_trace_buf_prepare() caller does
WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is
almost the same.
Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes
the meaning of _ONCE, but I think this is fine.
- 4947014 2932448 10104832 17984294 1126b26 vmlinux
+ 4948422 2932448 10104832 17985702 11270a6 vmlinux
on my build.
Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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|
perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL)
make no sense if hlist_empty(head). Change perf_syscall_enter/exit()
to check sys_data->{enter,exit}_event->perf_events beforehand.
Link: http://lkml.kernel.org/r/20130617170207.GA19806@redhat.com
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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empty
perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL)
make no sense if hlist_empty(head). Change perf_ftrace_function_call()
to check event_function.perf_events beforehand.
Link: http://lkml.kernel.org/r/20130617170204.GA19803@redhat.com
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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There have some mismatch between comments with
real function name, update it.
This patch also add some missed function arguments
description.
Link: http://lkml.kernel.org/r/51E3B3B2.4080307@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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For string without format specifiers, use trace_seq_puts()
or trace_seq_putc().
Link: http://lkml.kernel.org/r/51E3B3AC.1000605@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
[ fixed a trace_seq_putc(s, " ") to trace_seq_putc(s, ' ') ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core patches from Greg KH:
"Here are some driver core patches for 3.11-rc2. They aren't really
bugfixes, but a bunch of new helper macros for drivers to properly
create attribute groups, which drivers and subsystems need to fix up a
ton of race issues with incorrectly creating sysfs files (binary and
normal) after userspace has been told that the device is present.
Also here is the ability to create binary files as attribute groups,
to solve that race condition, which was impossible to do before this,
so that's my fault the drivers were broken.
The majority of the .c changes is indenting and moving code around a
bit. It affects no existing code, but allows the large backlog of 70+
patches that I already have created to start flowing into the
different subtrees, instead of having to live in my driver-core tree,
causing merge nightmares in linux-next for the next few months.
These were finalized too late for the -rc1 merge window, which is why
they were didn't make that pull request, testing and review from
others didn't happen until a few weeks ago, and then there's the whole
distraction of the past few days, which prevented these from getting
to you sooner, sorry about that.
Oh, and there's a bugfix for the documentation build warning in here
as well. All of these have been in linux-next this week, with no
reported problems"
* tag 'driver-core-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
driver-core: fix new kernel-doc warning in base/platform.c
sysfs: use file mode defines from stat.h
sysfs: add more helper macro's for (bin_)attribute(_groups)
driver core: add default groups to struct class
driver core: Introduce device_create_groups
sysfs: prevent warning when only using binary attributes
sysfs: add support for binary attributes in groups
driver core: device.h: add RW and RO attribute macros
sysfs.h: add BIN_ATTR macro
sysfs.h: add ATTRIBUTE_GROUPS() macro
sysfs.h: add __ATTR_RW() macro
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Linux as a guest on KVM hypervisor, the only user of the pvclock
vsyscall interface, does not require notification on task migration
because:
1. cpu ID number maps 1:1 to per-CPU pvclock time info.
2. per-CPU pvclock time info is updated if the
underlying CPU changes.
3. that version is increased whenever underlying CPU
changes.
Which is sufficient to guarantee nanoseconds counter
is calculated properly.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
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When building the htmldocs (in verbose mode), scripts/kernel-doc
reports the follwing type of warnings:
Warning(kernel/sched/core.c:936): No description found for return value of 'task_curr'
...
Fix those by:
- adding the missing descriptions
- using "Return" sections for the descriptions
Signed-off-by: Yacine Belkadi <yacine.belkadi.1@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373654747-2389-1-git-send-email-yacine.belkadi.1@gmail.com
[ While at it, fix the cpupri_set() explanation. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Introduce a method for run-time instruction patching on a live SMP kernel
based on int3 breakpoint, completely avoiding the need for stop_machine().
The way this is achieved:
- add a int3 trap to the address that will be patched
- sync cores
- update all but the first byte of the patched range
- sync cores
- replace the first byte (int3) by the first byte of
replacing opcode
- sync cores
According to
http://lkml.indiana.edu/hypermail/linux/kernel/1001.1/01530.html
synchronization after replacing "all but first" instructions should not
be necessary (on Intel hardware), as the syncing after the subsequent
patching of the first byte provides enough safety.
But there's not only Intel HW out there, and we'd rather be on a safe
side.
If any CPU instruction execution would collide with the patching,
it'd be trapped by the int3 breakpoint and redirected to the provided
"handler" (which would typically mean just skipping over the patched
region, acting as "nop" has been there, in case we are doing nop -> jump
and jump -> nop transitions).
Ftrace has been using this very technique since 08d636b ("ftrace/x86:
Have arch x86_64 use breakpoints instead of stop machine") for ages
already, and jump labels are another obvious potential user of this.
Based on activities of Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
a few years ago.
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1307121102440.29788@pobox.suse.cz
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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