Tracing can be very helpful to debug the kernel. When DEBUG_KERNEL is
enabled it is nice to enable the trace menu as well.
This patch only make the tracing menu enabled by default, it does not
make any of the tracers enabled. And the menu is only enabled by
default if DEBUG_KERNEL is enabled.
[ Impact: show tracing options to those debugging the kernel ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The system enabling of events uses the same code as the set_event file.
It passes in the name of the system to the parser and that will enable
all the events that has that system as a name.
The problem is that it will also enable events with the same name as the
system.
If you have system name foo, and system name bar, but within the system
bar, there exists an event called foo. By setting the system name foo,
you will also be enabling the event foo in the system bar. This is not
an expected result.
The solution is to pass in "foo:*", which will only enable the system
foo and not events called foo.
[ Impact: prevent accidental enabling of events with same name as a system ]
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Ingo Molnar thought that the code to calculate the time in cond_resched
is a bit too ugly and is not needed. This patch removes it and replaces
it with a simple call to cond_resched. I kept the comment that explains
the reason for the cond_resched.
[ Impact: remove ugly code ]
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Merge reason: this topic is ready for upstream now. It passed
Oleg's review and Andrew had no further mm/*
objections/observations either.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge reason: tracing/core was on a .30-rc1 base and was missing out on
on a handful of tracing fixes present in .30-rc5-almost.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In filter_add_subsystem_pred() we should release event_mutex before
calling filter_free_subsystem_preds(), since both functions hold
event_mutex.
[ Impact: fix deadlock when writing invalid pred into subsystem filter ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: tzanussi@gmail.com
Cc: a.p.zijlstra@chello.nl
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
LKML-Reference: <4A028993.7020509@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we set a filter for an event, such as:
echo "name == my_lock_name" > \
/debug/tracing/events/lockdep/lock_acquired/filter
then the following order of token type is parsed:
- space
- operator
- parentheses
- operand
Because the operators and parentheses have a higher precedence
than the operand characters, which is normal, then we can't
use any string containing such special characters:
()=<>!&|
To get this support and also avoid ambiguous intepretation from
the parser or the human, we can do it using double quotes so that
we keep the usual languages habits.
Then after this patch you can still declare string condition like
before:
echo name == myname
But if you want to compare against a string containing an operator
character, you can use double quotes:
echo 'name == "&myname"'
Don't forget to include the whole expression into single quotes or
the double ones will be eaten by echo.
[ Impact: support strings with special characters for tracing filters ]
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Currently the filtering infrastructure supports well the
numeric types and fixed sized array types.
But the recently added __string() field uses a specific
indirect offset mechanism which requires a specific
predicate. Until now it wasn't supported.
This patch adds this support and implies very few changes,
only a new predicate is needed, the management of this specific
field can be done through the usual string helpers in the
filtering infrastructure.
[ Impact: support all kinds of strings in the tracing filters ]
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
With the current event directory, you can only enable individual events.
The file debugfs/tracing/set_event is used to be able to enable or
disable several events at once. But that can still be awkward.
This patch adds hierarchical enabling of events. That is, each directory
in debugfs/tracing/events has an "enable" file. This file can enable
or disable all events within the directory and below.
# echo 1 > /debugfs/tracing/events/enable
will enable all events.
# echo 1 > /debugfs/tracing/events/sched/enable
will enable all events in the sched subsystem.
# echo 1 > /debugfs/tracing/events/enable
# echo 0 > /debugfs/tracing/events/irq/enable
will enable all events, but then disable just the irq subsystem events.
When reading one of these enable files, there are four results:
0 - all events this file affects are disabled
1 - all events this file affects are enabled
X - there is a mixture of events enabled and disabled
? - this file does not affect any event
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Li Zefan found that there's a race using the event ids of events and
modules. When a module is loaded, an event id is incremented. We only
have 16 bits for event ids (65536) and there is a possible (but highly
unlikely) race that we could load and unload a module that registers
events so many times that the event id counter overflows.
When it overflows, it then restarts and goes looking for available
ids. An id is available if it was added by a module and released.
The race is if you have one module add an id, and then is removed.
Another module loaded can use that same event id. But if the old module
still had events in the ring buffer, the new module's call back would
get bogus data. At best (and most likely) the output would just be
garbage. But if the module for some reason used pointers (not recommended)
then this could potentially crash.
The safest thing to do is just reset the ring buffer if a module that
registered events is removed.
[ Impact: prevent unpredictable results of event id overflows ]
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <49FEAFD0.30106@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ring buffer benchmark/test runs a producer for 10 seconds.
This is done with preemption and interrupts enabled. But if the kernel
is not compiled with CONFIG_PREEMPT, it basically stops everything
but interrupts for 10 seconds.
Although this is just a test and is not for production, this attribute
can be quite annoying. It can also spawn badness elsewhere.
This patch solves the issues by calling "cond_resched" when the system
is not compiled with CONFIG_PREEMPT. It also keeps track of the time
spent to call cond_resched such that it does not go against the
time calculations. That is, if the task schedules away, the time scheduled
out is removed from the test data. Note, this only works for non PREEMPT
because we do not know when the task is scheduled out if we have PREEMPT
enabled.
[ Impact: prevent test from stopping the world for 10 seconds ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Ingo Molnar thought the code would be cleaner if we used a function call
instead of a goto for moving the tail page. After implementing this,
it seems that gcc still inlines the result and the output is pretty much
the same. Since this is considered a cleaner approach, might as well
implement it.
[ Impact: code clean up ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The result of the allocation of the ring buffer read page in the
ring buffer bench mark does not check the return to see if a page
was actually allocated. This patch fixes that.
[ Impact: avoid NULL dereference ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The code in __rb_reserve_next checks on page overflow if it is the
original commiter and then resets the page back to the original
setting. Although this is fine, and the code is correct, it is
a bit fragil. Some experimental work I did breaks it easily.
The better and more robust solution is to have all commiters that
overflow the page, simply subtract what they added.
[ Impact: more robust ring buffer account management ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This compiler warning:
CC kernel/trace/trace_output.o
kernel/trace/trace_output.c: In function ‘register_ftrace_event’:
kernel/trace/trace_output.c:544: warning: ‘list’ may be used uninitialized in this function
Is wrong as 'list' is always initialized - but GCC (4.3.2) does not
recognize this relationship properly.
Work around the warning by initializing the variable to NULL.
[ Impact: fix false positive compiler warning ]
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This attempts to clarify names utilized during block I/O remap
operations (partition, volume manager). It correctly matches up the
/from/ information for both device & sector. This takes in the concept
from Kosaki Motohiro and extends it to include better naming for the
"device_from" field.
[ Impact: cleanup ]
Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49FF4FAE.3000301@hp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
A module will add/remove its trace events when it gets loaded/unloaded, so
the ftrace_events list is not "const", and concurrent access needs to be
protected.
This patch thus fixes races between loading/unloding modules and read
'available_events' or read/write 'set_event', etc.
Below shows how to reproduce the race:
# for ((; ;)) { cat /mnt/tracing/available_events; } > /dev/null &
# for ((; ;)) { insmod trace-events-sample.ko; rmmod sample; } &
After a while:
BUG: unable to handle kernel paging request at 0010011c
IP: [<c1080f27>] t_next+0x1b/0x2d
...
Call Trace:
[<c10c90e6>] ? seq_read+0x217/0x30d
[<c10c8ecf>] ? seq_read+0x0/0x30d
[<c10b4c19>] ? vfs_read+0x8f/0x136
[<c10b4fc3>] ? sys_read+0x40/0x65
[<c1002a68>] ? sysenter_do_call+0x12/0x36
[ Impact: fix races when concurrent accessing ftrace_events list ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4A00F709.3080800@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When unloading a module, memory allocated by init_preds() and
trace_define_field() is not freed.
[ Impact: fix memory leak ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4A00F6E0.3040503@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds code that can benchmark the ring buffer as well as
test it. This code can be compiled into the kernel (not recommended)
or as a module.
A separate ring buffer is used to not interfer with other users, like
ftrace. It creates a producer and a consumer (option to disable creation
of the consumer) and will run for 10 seconds, then sleep for 10 seconds
and then repeat.
While running, the producer will write 10 byte loads into the ring
buffer with just putting in the current CPU number. The reader will
continually try to read the buffer. The reader will alternate from reading
the buffer via event by event, or by full pages.
The output is a pr_info, thus it will fill up the syslogs.
Starting ring buffer hammer
End ring buffer hammer
Time: 9000349 (usecs)
Overruns: 12578640
Read: 5358440 (by events)
Entries: 0
Total: 17937080
Missed: 0
Hit: 17937080
Entries per millisec: 1993
501 ns per entry
Sleeping for 10 secs
Starting ring buffer hammer
End ring buffer hammer
Time: 9936350 (usecs)
Overruns: 0
Read: 28146644 (by pages)
Entries: 74
Total: 28146718
Missed: 0
Hit: 28146718
Entries per millisec: 2832
353 ns per entry
Sleeping for 10 secs
Time: is the time the test ran
Overruns: the number of events that were overwritten and not read
Read: the number of events read (either by pages or events)
Entries: the number of entries left in the buffer
(the by pages will only read full pages)
Total: Entries + Read + Overruns
Missed: the number of entries that failed to write
Hit: the number of entries that were written
The above example shows that it takes ~353 nanosecs per entry when
there is a reader, reading by pages (and no overruns)
The event by event reader slowed the producer down to 501 nanosecs.
[ Impact: see how changes to the ring buffer affect stability and performance ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In the hot path of the ring buffer "__rb_reserve_next" there's a big
if statement that does not even return back to the work flow.
code;
if (cross to next page) {
[ lots of code ]
return;
}
more code;
The condition is even the unlikely path, although we do not denote it
with an unlikely because gcc is fine with it. The condition is true when
the write crosses a page boundary, and we need to start at a new page.
Having this if statement makes it hard to read, but calling another
function to do the work is also not appropriate, because we are using a lot
of variables that were set before the if statement, and we do not want to
send them as parameters.
This patch changes it to a goto:
code;
if (cross to next page)
goto next_page;
more code;
return;
next_page:
[ lots of code]
This makes the code easier to understand, and a bit more obvious.
The output from gcc is practically identical. For some reason, gcc decided
to use different registers when I switched it to a goto. But other than that,
the logic is the same.
[ Impact: easier to read code ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When adding the EXPORT_SYMBOL to some of the tracing API, I accidently
used EXPORT_SYMBOL instead of EXPORT_SYMBOL_GPL. This patch fixes
that mistake.
[ Impact: export the tracing code only for GPL modules ]
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As a precaution, it is best to disable writing to the ring buffers
when reseting them.
[ Impact: prevent weird things if write happens during reset ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In the swap page ring buffer code that is used by the ftrace splice code,
we scan the page to increment the counter of entries read.
With the number of entries already in the page we simply need to add it.
[ Impact: speed up reading page from ring buffer ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, when the ring buffer writer overflows the buffer and must
write over non consumed data, we increment the overrun counter by
reading the entries on the page we are about to overwrite. This reads
the entries one by one.
This is not very effecient. This patch adds another entry counter
into each buffer page descriptor that keeps track of the number of
entries on the page. Now on overwrite, the overrun counter simply
needs to add the number of entries that is on the page it is about
to overwrite.
[ Impact: speed up of ring buffer in overwrite mode ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The entries counter in cpu buffer is not atomic. It can be updated by
other interrupts or from another CPU (readers).
But making entries into "atomic_t" causes an atomic operation that can
hurt performance. Instead we convert it to a local_t that will increment
a counter with a local CPU atomic operation (if the arch supports it).
Instead of fighting with readers and overwrites that decrement the counter,
I added a "read" counter. Every time a reader reads an entry it is
incremented.
We already have a overrun counter and with that, the entries counter and
the read counter, we can calculate the total number of entries in the
buffer with:
(entries - overrun) - read
As long as the total number of entries in the ring buffer is less than
the word size, this will work. But since the entries counter was previously
a long, this is no different than what we had before.
Thanks to Andrew Morton for pointing out in the first version that
atomic_t does not replace unsigned long. I switched to atomic_long_t
even though it is signed. A negative count is most likely a bug.
[ Impact: keep accurate count of cpu buffer entries ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch adds stats to the ftrace ring buffers:
# cat /debugfs/tracing/per_cpu/cpu0/stats
entries: 42360
overrun: 30509326
commit overrun: 0
nmi dropped: 0
Where entries are the total number of data entries in the buffer.
overrun is the number of entries not consumed and were overwritten by
the writer.
commit overrun is the number of entries dropped due to nested writers
wrapping the buffer before the initial writer finished the commit.
nmi dropped is the number of entries dropped due to the ring buffer
lock being held when an nmi was going to write to the ring buffer.
Note, this field will be meaningless and will go away when the ring
buffer becomes lockless.
[ Impact: let userspace know what is happening in the ring buffers ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The WARN_ON in the ring buffer when a commit is preempted and the
buffer is filled by preceding writes can happen in normal operations.
The WARN_ON makes it look like a bug, not to mention, because
it does not stop tracing and calls printk which can also recurse, this
is prone to deadlock (the WARN_ON is not in a position to recurse).
This patch removes the WARN_ON and replaces it with a counter that
can be retrieved by a tracer. This counter is called commit_overrun.
While at it, I added a nmi_dropped counter to count any time an NMI entry
is dropped because the NMI could not take the spinlock.
[ Impact: prevent deadlock by printing normal case warning ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
I'm adding a module to do a series of tests on the ring buffer as well
as benchmarks. This module needs to have more of the ring buffer API
exported. There's nothing wrong with reading the ring buffer from a
module.
[ Impact: allow modules to read pages from the ring buffer ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Replace the current event parser hack with a better one. Filters are
no longer specified predicate by predicate, but all at once and can
use parens and any of the following operators:
numeric fields:
==, !=, <, <=, >, >=
string fields:
==, !=
predicates can be combined with the logical operators:
&&, ||
examples:
"common_preempt_count > 4" > filter
"((sig >= 10 && sig < 15) || sig == 17) && comm != bash" > filter
If there was an error, the erroneous string along with an error
message can be seen by looking at the filter e.g.:
((sig >= 10 && sig < 15) || dsig == 17) && comm != bash
^
parse_error: Field not found
Currently the caret for an error always appears at the beginning of
the filter; a real position should be used, but the error message
should be useful even without it.
To clear a filter, '0' can be written to the filter file.
Filters can also be set or cleared for a complete subsystem by writing
the same filter as would be written to an individual event to the
filter file at the root of the subsytem. Note however, that if any
event in the subsystem lacks a field specified in the filter being
set, the set will fail and all filters in the subsytem are
automatically cleared. This change from the previous version was made
because using only the fields that happen to exist for a given event
would most likely result in a meaningless filter.
Because the logical operators are now implemented as predicates, the
maximum number of predicates in a filter was increased from 8 to 16.
[ Impact: add new, extended trace-filter implementation ]
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <1240905899.6416.121.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The new filter comparison ops need to be able to distinguish between
signed and unsigned field types, so add an is_signed flag/param to the
event field struct/trace_define_fields(). Also define a simple macro,
is_signed_type() to determine the signedness at compile time, used in the
trace macros. If the is_signed_type() macro won't work with a specific
type, a new slightly modified version of TRACE_FIELD() called
TRACE_FIELD_SIGN(), allows the signedness to be set explicitly.
[ Impact: extend trace-filter code for new feature ]
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <1240905893.6416.120.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Create a new event_filter object, and move the pred-related members
out of the call and subsystem objects and into the filter object - the
details of the filter implementation don't need to be exposed in the
call and subsystem in any case, and it will also help make the new
parser implementation a little cleaner.
[ Impact: refactor trace-filter code to prepare for new features ]
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <1240905887.6416.119.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The pages allocated for the splice binary buffer did not initialize
the ref count correctly. This caused pages not to be freed and causes
a drastic memory leak.
Thanks to logdev I was able to trace the tracer to find where the leak
was.
[ Impact: stop memory leak when using splice ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The warning output in trace_recursive_lock uses %d for a long when
it should be %ld.
[ Impact: fix compile warning ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Splice works with pages, it is much more effecient to use an entire
page than to copy bits over several pages.
Using logdev to trace the internals of the splice mechanism, I was
able to see that splice can be very aggressive. When tracing is
occurring, and the reader caught up to the writer, and the writer
is on the reader page, the reader will copy what is there into the
splice page. Splice may iterate over several pages and if the
writer is still writing to the page, the reader will keep copying
bits to new pages to pass to userspace.
This patch changes it to only pass data to userspace if the page
is full (the writer has left the page). This has a small side effect
that splice can not read a partial page, and must wait for the
page to fill. This should not be an issue. If tracing has stopped,
then a use of "read" will still read all of the page.
[ Impact: better performance for ring buffer splice code ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The splice code allocates a page even when the ring buffer is empty.
It detects the ring buffer being empty when it it fails to copy
anything from the ring buffer into the page.
This patch adds a check to see if there is anything in the ring buffer
before allocating a page.
Thanks to logdev for letting me trace the tracer to find this.
[ Impact: speed up due to removing unnecessary allocation ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The pages allocated for the splice binary buffer did not initialize
the ref count correctly. This caused pages not to be freed and causes
a drastic memory leak.
Thanks to logdev I was able to trace the tracer to find where the leak
was.
[ Impact: stop memory leak when using splice ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ftrace_dump is used for printing out the contents of the ftrace ring buffer
to the console on failure. Currently it uses a spinlock to synchronize
the output from multiple failures on different CPUs. This spin lock
currently is a normal spinlock and can cause issues with lockdep and
lock tracing.
This patch converts it to raw since it is for error handling only.
The lock is local to the ftrace_dump and is not used by any other
infrastructure.
[ Impact: prevent ftrace_dump from locking up by internal tracing ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
For proper module reference counting, the file_operations that modules use
must have the "owner" field set to the module. Unfortunately, the trace events
use share file_operations. The same file_operations are used by all both
kernel core and all modules.
This patch makes the modules allocate their own file_operations and
copies the functions from the core kernel. This allows those file
operations to be owned by the module.
Care is taken to free this code on module unload.
Thanks to Greg KH for reminding me that file_operations must be owned
by the module to have reference counting take place.
[ Impact: fix modular tracepoints / potential crash ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
With modules being able to add trace events, and the max trace event
counter is 16 bits (65536) we can overflow the counter easily
with a simple while loop adding and removing modules that contain
trace events.
This patch links together the registered trace events and on overflow
searches for available trace event ids. It will still fail if
over 65536 events are registered, but considering that a typical
kernel only has 22000 functions, 65000 events should be sufficient.
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Conflicts:
arch/x86/kernel/ptrace.c
Merge reason: fix the conflict above, and also pick up the CONFIG_BROKEN
dependency change from upstream so that we can remove it
here.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
RB_MAX_SMALL_DATA = 28bytes is too small for most tracers, it wastes
an 'u32' to save the actually length for events which data size > 28.
This fix uses compressed event header and enlarges RB_MAX_SMALL_DATA.
[ Impact: saves about 0%-12.5%(depends on tracer) memory in ring_buffer ]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <49F13189.3090000@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The events exported by TRACE_EVENT are automated and are guaranteed
to be correct when used.
The internal ftrace structures on the other hand are more manually
exported. These require the ftrace maintainer to make sure they
are up to date.
This patch adds a size check to help flag when a type changes in
an internal ftrace data structure, and the update needs to be reflected
in the export.
If a export is incorrect, then the only harm is that the user space
tools will not know how to correctly read the internal structures of
ftrace.
[ Impact: help prevent inconsistent ftrace format print outs ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
With the new event tracing registration, we must increase the number
of events that can be registered. Currently the type field is only
one byte, which leaves us only 256 possible events.
Since we do not save the CPU number in the tracer anymore (it is determined
by the per cpu ring buffer that is used) we have an extra byte to use.
This patch increases the size of type from 1 byte (256 events) to
2 bytes (65,536 events).
It also adds a WARN_ON_ONCE if we exceed that limit.
[ Impact: allow more than 255 events ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The code had the following outside the lock:
if (next != wakeup_task)
return;
pc = preempt_count();
/* The task we are waiting for is waking up */
data = wakeup_trace->data[wakeup_cpu];
On initialization, wakeup_task is NULL and wakeup_cpu -1. This code
is not under a lock. If wakeup_task is set on another CPU as that
task is waking up, we can see the wakeup_task before wakeup_cpu is
set. If we read wakeup_cpu while it is still -1 then we will have
a bad data pointer.
This patch moves the reading of wakeup_cpu within the protection of
the spinlock used to protect the writing of wakeup_cpu and wakeup_task.
[ Impact: remove possible race causing invalid pointer dereference ]
Reported-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
struct trace_entry->type is unsigned char, while trace event's id is
int type, thus for a event with id >= 256, it's entry->type is cast
to (id % 256), and then we can't see the trace output of this event.
# insmod trace-events-sample.ko
# echo foo_bar > /mnt/tracing/set_event
# cat /debug/tracing/events/trace-events-sample/foo_bar/id
256
# cat /mnt/tracing/trace_pipe
<...>-3548 [001] 215.091142: Unknown type 0
<...>-3548 [001] 216.089207: Unknown type 0
<...>-3548 [001] 217.087271: Unknown type 0
<...>-3548 [001] 218.085332: Unknown type 0
[ Impact: fix output for trace events with id >= 256 ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <49EEDB0E.5070207@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On boot up, to save memory, ftrace allocates the minimum buffer
which is two pages. Ftrace also goes through a series of tests
(when configured) on boot up. These tests can fill up a page within
a single interrupt.
The ring buffer also has a WARN_ON when it detects that the buffer was
completely filled within a single commit (other commits are allowed to
be nested).
Combine the small buffer on start up, with the tests that can fill more
than a single page within an interrupt, this can trigger the WARN_ON.
This patch makes the WARN_ON only happen when the ring buffer consists
of more than two pages.
[ Impact: prevent false WARN_ON in ftrace startup tests ]
Reported-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20090421094616.GA14561@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Suppose we would like to trace all tasks named '123', but this
will fail:
# echo 'parent_comm == 123' > events/sched/sched_process_fork/filter
bash: echo: write error: Invalid argument
Don't guess the type of the filter pred in filter_parse(), but instead
we check it in __filter_add_pred().
[ Impact: extend allowed filter field string values ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49ED8DEB.6000700@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If writing subsys->filter returns EINVAL or ENOSPC, the original
filters in subsys/ and subsys/events/ will be removed. This is
definitely wrong.
[ Impact: fix filter setting semantics on error condition ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49ED8DD2.2070700@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The startup tests for the event tracer also runs with the function
tracer enabled. The "wakeup" version of the trace commit was used
which can grab spinlocks. If a task was preempted by an NMI
that called a function being traced, it could deadlock due to the
function tracer trying to grab the same lock.
Thanks to Frederic Weisbecker for pointing out where the bug was.
Reported-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Althought using the irq level (hardirq_count, softirq_count and in_nmi)
was nice to detect bad recursion right away, but since the counters are
not atomically updated with respect to the interrupts, the function tracer
might trigger the test from an interrupt handler before the hardirq_count
is updated. This will trigger a false warning.
This patch converts the recursive detection to a simple counter.
If the depth is greater than 16 then the recursive detection will trigger.
16 is more than enough for any nested interrupts.
[ Impact: fix false positive trace recursion detection ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ring_buffer_event_discard is not tied to ring_buffer_lock_reserve.
It can be called inside or outside the reserve/commit. Even if it
is called inside the reserve/commit the commit part must also be called.
Only ring_buffer_discard_commit can be used as a replacement for
ring_buffer_unlock_commit.
This patch removes the trace_recursive_unlock from ring_buffer_event_discard
since it would be the wrong place to do so.
[Impact: prevent breakage in trace recursive testing ]
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The recursive tests to detect same level recursion in the ring buffers
did not account for the hard/softirq_counts to be shifted. Thus the
numbers could be larger than then mask to be tested.
This patch includes the shift for the calculation of the irq depth.
[ Impact: stop false positives in trace recursion detection ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The late_initcall calls a helper function instead of the proper
init event selftest function.
This update may have been lost due to conflicting merges.
[ Impact: fix compiler warning and call extended event trace self tests ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently we have two configs: EVENT_TRACING and EVENT_TRACER.
All tracers enable EVENT_TRACING. The EVENT_TRACER is only a
convenience to enable the EVENT_TRACING when no other tracers
are enabled.
The names EVENT_TRACER and EVENT_TRACING are too similar and confusing.
This patch renames EVENT_TRACER to ENABLE_EVENT_TRACING to be more
appropriate to what it actually does, as well as add a comment in
the help menu to explain the option's purpose.
[ Impact: rename config option to reduce confusion ]
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
During testing we often use randconfig to test various kernels.
The current configuration set up does not give an easy way to disable
all tracing with a single config. The case where randconfig would
test all tracing disabled is very unlikely.
This patch adds a config option to enable or disable all tracing.
It is hooked into the tracing menu just like other submenus are done.
[ Impact: allow randconfig to easily produce all traces disabled ]
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch makes the branch profiling into a choice selection:
None - no branch profiling
likely/unlikely - only profile likely/unlikely branches
all - profile all branches
The all profiler will also enable the likely/unlikely branches.
This does not change the way the profiler works or the dependencies
between the profilers.
What this patch does, is keep the branch profiling from being selected
by an allyesconfig make. The branch profiler is very intrusive and
it is known to break various architecture builds when selected as an
allyesconfig.
[ Impact: prevent branch profiler from being selected in allyesconfig ]
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In case of tracing recursion detection, we only get the stacktrace.
But the current context may be very useful to debug the issue.
This patch adds the softirq/hardirq/nmi context with the warning
using lockdep context display to have a familiar output.
v2: Use printk_once()
v3: drop {hardirq,softirq}_context which depend on lockdep,
only keep what is part of current->trace_recursion,
sufficient to debug the warning source.
[ Impact: print context necessary to debug recursion ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
trace_printk can be called from any context, including NMIs.
If this happens, then we must test for for recursion before
grabbing any spinlocks.
This patch prevents trace_printk from being called recursively.
[ Impact: prevent hard lockup in lockdep event tracer ]
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The tracing infrastructure allows for recursion. That is, an interrupt
may interrupt the act of tracing an event, and that interrupt may very well
perform its own trace. This is a recursive trace, and is fine to do.
The problem arises when there is a bug, and the utility doing the trace
calls something that recurses back into the tracer. This recursion is not
caused by an external event like an interrupt, but by code that is not
expected to recurse. The result could be a lockup.
This patch adds a bitmask to the task structure that keeps track
of the trace recursion. To find the interrupt depth, the following
algorithm is used:
level = hardirq_count() + softirq_count() + in_nmi;
Here, level will be the depth of interrutps and softirqs, and even handles
the nmi. Then the corresponding bit is set in the recursion bitmask.
If the bit was already set, we know we had a recursion at the same level
and we warn about it and fail the writing to the buffer.
After the data has been committed to the buffer, we clear the bit.
No atomics are needed. The only races are with interrupts and they reset
the bitmask before returning anywy.
[ Impact: detect same irq level trace recursion ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Not all the necessary symbols were exported to allow for tracing
by modules. This patch adds them in.
[ Impact: allow modules to commit data to the ring buffer ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch adds a filter_mutex to prevent the filter predicates from
being accessed concurrently by various external functions.
It's based on a previous patch by Li Zefan:
"[PATCH 7/7] tracing/filters: make filter preds RCU safe"
v2 changes:
- fixed wrong value returned in a add_subsystem_pred() failure case
noticed by Li Zefan.
[ Impact: fix trace filter corruption/crashes on parallel access ]
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: paulmck@linux.vnet.ibm.com
LKML-Reference: <1239946028.6639.13.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We can find some bugs in the trace events if we stress the writes as well.
The function tracer is a good way to stress the events.
[ Impact: extend scope of event tracer self-tests ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090416161746.604786131@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Export the cached task comms to userspace. This allows user apps to translate
the pids from a trace into their respective task command lines.
[ Impact: let userspace apps reading binary buffer know comm's of pids ]
Signed-off-by: Avadh Patel <avadh4all@gmail.com>
[ added error checking and use of buf pointer to index file_buf ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, every thing needed to read the binary output from the
ring buffers is available, with the exception of the way the ring
buffers handles itself internally.
This patch creates two special files in the debugfs/tracing/events
directory:
# cat /debug/tracing/events/header_page
field: u64 timestamp; offset:0; size:8;
field: local_t commit; offset:8; size:8;
field: char data; offset:16; size:4080;
# cat /debug/tracing/events/header_event
type : 2 bits
len : 3 bits
time_delta : 27 bits
array : 32 bits
padding : type == 0
time_extend : type == 1
data : type == 3
This is to allow a userspace app to see if the ring buffer format changes
or not.
[ Impact: allow userspace apps to know of ringbuffer format changes ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As events start to become popular, and the new way to add tracing
infrastructure into ftrace, it is important to catch any problems
that might happen with a mistake in the TRACE_EVENT macro.
This patch introduces a startup self test on the registered trace
events. Note, it can only do a generic test, any type of testing that
needs more involement is needed to be implemented by the tracepoint
creators.
The test goes down one by one enabling a trace point and running
some random tasks (random in the sense that I just made them up).
Those tasks are creating threads, grabbing mutexes and spinlocks
and using workqueues.
After testing each event individually, it does the same test after
enabling each system of trace points. Like sched, irq, lockdep.
Then finally it enables all tracepoints and performs the tasks again.
The output to the console on bootup will look like this when everything
works:
Running tests on trace events:
Testing event kfree_skb: OK
Testing event kmalloc: OK
Testing event kmem_cache_alloc: OK
Testing event kmalloc_node: OK
Testing event kmem_cache_alloc_node: OK
Testing event kfree: OK
Testing event kmem_cache_free: OK
Testing event irq_handler_exit: OK
Testing event irq_handler_entry: OK
Testing event softirq_entry: OK
Testing event softirq_exit: OK
Testing event lock_acquire: OK
Testing event lock_release: OK
Testing event sched_kthread_stop: OK
Testing event sched_kthread_stop_ret: OK
Testing event sched_wait_task: OK
Testing event sched_wakeup: OK
Testing event sched_wakeup_new: OK
Testing event sched_switch: OK
Testing event sched_migrate_task: OK
Testing event sched_process_free: OK
Testing event sched_process_exit: OK
Testing event sched_process_wait: OK
Testing event sched_process_fork: OK
Testing event sched_signal_send: OK
Running tests on trace event systems:
Testing event system skb: OK
Testing event system kmem: OK
Testing event system irq: OK
Testing event system lockdep: OK
Testing event system sched: OK
Running tests on all trace events:
Testing all events: OK
[ folded in:
tracing: add #include <linux/delay.h> to fix build failure in test_work()
This build failure occured on a few rare configs:
kernel/trace/trace_events.c: In function ‘test_work’:
kernel/trace/trace_events.c:975: error: implicit declaration of function ‘udelay’
kernel/trace/trace_events.c:980: error: implicit declaration of function ‘msleep’
delay.h is included in way too many other headers, hiding cases
where new usage is added without header inclusion.
[ Impact: build fix ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
]
[ Impact: add event tracer self-tests ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The hooks in the module code for the function tracer must be called
before any of that module code runs. The function tracer hooks
modify the module (replacing calls to mcount to nops). If the code
is executed while the change occurs, then the CPU can take a GPF.
To handle the above with a bit of paranoia, I originally implemented
the hooks as calls directly from the module code.
After examining the notifier calls, it looks as though the start up
notify is called before any of the module's code is executed. This makes
the use of the notify safe with ftrace.
Only the startup notify is required to be "safe". The shutdown simply
removes the entries from the ftrace function list, and does not modify
any code.
This change has another benefit. It removes a issue with a reverse dependency
in the mutexes of ftrace_lock and module_mutex.
[ Impact: fix lock dependency bug, cleanup ]
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When current tracer is set to blk tracer, TRACE_ITER_CONTEXT_INFO is
unset, but actually context-info is printed:
pdflush-431 [000] 821.181576: 8,0 P N [pdflush]
And then if we enable TRACE_ITER_CONTEXT_INFO:
# echo context-info > trace_options
We'll see context-info printed twice. What's worse, when we use blk
tracer and trace events at the same time, we'll see no context-info
for trace events at all:
jbd2_commit_logging: dev dm-0:8 transaction 333227
jbd2_end_commit: dev dm-0:8 transaction 333227 head 332814
rm-25433 [001] 9578.307485: 8,18 m N cfq25433 slice expired t=0
rm-25433 [001] 9578.307486: 8,18 m N cfq25433 put_queue
This patch adds blk_tracer->set_flags(), and context-info flag is unset
only when we set the output to classic mode.
Note after this patch, one should unset context-info explicitly if he
wants to get binary output that can be parsed by blkparse:
# echo nocontext-info > trace_options
# echo bin > trace_options
# echo blk > current_tracer
# cat trace_pipe | blkparse -i -
Reported-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49E54E60.50408@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The previous patch adds support to trace a single partition for
relay+ioctl blktrace, and this patch is for ftrace plugin blktrace:
# echo 1 > /sys/block/sda/sda7/enable
# cat start_lba
102398373
# cat end_lba
102703545
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Shawn Du <duyuyang@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49E42646.4060608@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Though one can specify '-d /dev/sda1' when using blktrace, it still
traces the whole sda.
To support per-partition tracing, when we start tracing, we initialize
bt->start_lba and bt->end_lba to the start and end sector of that
partition.
Note some actions are per device, thus we don't filter 0-sector events.
The original patch and discussion can be found here:
http://marc.info/?l=linux-btrace&m=122949374214540&w=2
Signed-off-by: Shawn Du <duyuyang@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49E42620.4050701@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
Create a sub directory in include/trace called events to keep the
trace point headers in their own separate directory. Only headers that
declare trace points should be defined in this directory.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Impact: compile fix
The addition of TRACE_EVENT for modules breaks the build for when
modules are disabled. This code fixes that.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Impact: allow modules to add TRACE_EVENTS on load
This patch adds the final hooks to allow modules to use the TRACE_EVENT
macro. A notifier and a data structure are used to link the TRACE_EVENTs
defined in the module to connect them with the ftrace event tracing system.
It also adds the necessary automated clean ups to the trace events when a
module is removed.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Impact: let modules add trace events
The trace event code requires some functions to be exported to allow
modules to use TRACE_EVENT. This patch adds EXPORT_SYMBOL_GPL to the
necessary functions.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Impact: makes it possible to define events in modules
The events are created by reading down the section that they are linked
in by the macros. But this is not scalable to modules. This patch converts
the manipulations to use a global link list, and on boot up it adds
the items in the section to the list.
This change will allow modules to add their tracing events to the list as
well.
Note, this change alone does not permit modules to use the TRACE_EVENT macros,
but the change is needed for them to eventually do so.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch moves the ftrace creation into include/trace/ftrace.h and
simplifies the work of developers in adding new tracepoints.
Just the act of creating the trace points in include/trace and including
define_trace.h will create the events in the debugfs/tracing/events
directory.
This patch removes the need of include/trace/trace_events.h
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In preparation to allowing trace events to happen in modules, we need
to move some of the local declarations in the kernel/trace directory
into include/linux.
This patch simply moves the declarations and performs no context changes.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In the process to make TRACE_EVENT macro work for modules, the trace_seq
operations must be available for core kernel code.
These operations are quite useful and can be used for other implementations.
The main idea is that we create a trace_seq handle that acts very much
like the seq_file handle.
struct trace_seq *s = kmalloc(sizeof(*s, GFP_KERNEL);
trace_seq_init(s);
trace_seq_printf(s, "some data %d\n", variable);
printk("%s", s->buffer);
The main use is to allow a top level function call several other functions
that may store printf like data into the buffer. Then at the end, the top
level function can process all the data with any method it would like to.
It could be passed to userspace, output via printk or even use seq_file:
trace_seq_to_user(s, ubuf, cnt);
seq_puts(m, s->buffer);
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Jeremy Fitzhardinge reported this build failure:
LD .tmp_vmlinux1
arch/x86/kernel/built-in.o: In function `ds_take_timestamp':
git/linux/arch/x86/kernel/ds.c:1380: undefined reference to `trace_clock_global'
git/linux/arch/x86/kernel/ds.c:1380: undefined reference to `trace_clock_global'
Which is due to !CONFIG_TRACING && CONFIG_X86_DS=y.
Expose the trace clock code to CONFIG_X86_DS as well.
[ Unfortunately librarizing doesnt work well - ancient architectures
with no raw_local_irq_save() primitive break the build. ]
Reported-by: Jeremy Fitzhardinge <jeremy@goop.org>
LKML-Reference: <49E4413F.7070700@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
Neil Horman (et. al.) criticized the way the trace events were broken up
into two files. The reason for that was that ftrace needed to separate out
the declarations from where the #include <linux/tracepoint.h> was used.
It then dawned on me that the tracepoint.h header only needs to define the
TRACE_EVENT macro if it is not already defined.
The solution is simply to test if TRACE_EVENT is defined, and if it is not
then the linux/tracepoint.h header can define it. This change consolidates
all the <traces>.h and <traces>_event_types.h into the <traces>.h file.
Reported-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Theodore Tso <tytso@mit.edu>
Reported-by: Jiaying Zhang <jiayingz@google.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch allows event filters to be safely removed or switched
on-the-fly while avoiding the use of rcu or the suspension of tracing of
previous versions.
It does it by adding a new filter_pred_none() predicate function which
does nothing and by never deallocating either the predicates or any of
the filter_pred members used in matching; the predicate lists are
allocated and initialized during ftrace_event_calls initialization.
Whenever a filter is removed or replaced, the filter_pred_* functions
currently in use by the affected ftrace_event_call are immediately
switched over to to the filter_pred_none() function, while the rest of
the filter_pred members are left intact, allowing any currently
executing filter_pred_* functions to finish up, using the values they're
currently using.
In the case of filter replacement, the new predicate values are copied
into the old predicates after the above step, and the filter_pred_none()
functions are replaced by the filter_pred_* functions for the new
filter. In this case, it is possible though very unlikely that a
previous filter_pred_* is still running even after the
filter_pred_none() switch and the switch to the new filter_pred_*. In
that case, however, because nothing has been deallocated in the
filter_pred, the worst that can happen is that the old filter_pred_*
function sees the new values and as a result produces either a false
positive or a false negative, depending on the values it finds.
So one downside to this method is that rarely, it can produce a bad
match during the filter switch, but it should be possible to live with
that, IMHO.
The other downside is that at least in this patch the predicate lists
are always pre-allocated, taking up memory from the start. They could
probably be allocated on first-use, and de-allocated when tracing is
completely stopped - if this patch makes sense, I could create another
one to do that later on.
Oh, and it also places a restriction on the size of __arrays in events,
currently set to 128, since they can't be larger than the now embedded
str_val arrays in the filter_pred struct.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: paulmck@linux.vnet.ibm.com
LKML-Reference: <1239610670.6660.49.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch changes filter_check_discard() to make use of the new
ring_buffer_discard_commit() function and modifies the current users to
call the old commit function in the non-discard case.
It also introduces a version of filter_check_discard() that uses the
global trace buffer (filter_current_check_discard()) for those cases.
v2 changes:
- fix compile error noticed by Ingo Molnar
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1239178554.10295.36.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add a new config option, CONFIG_EVENT_TRACING that gets selected
when CONFIG_TRACING is selected and adds everything needed by the stuff
in trace_export - basically all the event tracing support needed by e.g.
bprint, minus the actual events, which are only included if
CONFIG_EVENT_TRACER is selected.
So CONFIG_EVENT_TRACER can be used to turn on or off the generated events
(what I think of as the 'event tracer'), while CONFIG_EVENT_TRACING turns
on or off the base event tracing support used by both the event tracer and
the other things such as bprint that can't be configured out.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1239178441.10295.34.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The ring_buffer_discard_commit makes better usage of the ring_buffer
when an event has been discarded. It tries to remove it completely if
possible.
This patch converts the trace event filtering to use
ring_buffer_discard_commit instead of the ring_buffer_event_discard.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The ring_buffer_discard_commit is similar to ring_buffer_event_discard
but it can only be done on an event that has yet to be commited.
Unpredictable results can happen otherwise.
The main difference between ring_buffer_discard_commit and
ring_buffer_event_discard is that ring_buffer_discard_commit will try
to free the data in the ring buffer if nothing has addded data
after the reserved event. If something did, then it acts almost the
same as ring_buffer_event_discard followed by a
ring_buffer_unlock_commit.
Note, either ring_buffer_commit_discard and ring_buffer_unlock_commit
can be called on an event, not both.
This commit also exports both discard functions to be usable by
GPL modules.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Frederic Weisbecker suggested that the trace_special event shouldn't be
filterable; this patch adds a TRACE_EVENT_FORMAT_NOFILTER event macro
that allows an event format to be exported without having a filter
attached, and removes filtering from the trace_special event.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds run-time field descriptions to all the event formats
exported using TRACE_EVENT_FORMAT. It also hooks up all the tracers
that use them (i.e. the tracers in the 'ftrace subsystem') so they can
also have their output filtered by the event-filtering mechanism.
When I was testing this, there were a couple of things that fooled me
into thinking the filters weren't working, when actually they were -
I'll mention them here so others don't make the same mistakes (and file
bug reports. ;-)
One is that some of the tracers trace multiple events e.g. the
sched_switch tracer uses the context_switch and wakeup events, and if
you don't set filters on all of the traced events, the unfiltered output
from the events without filters on them can make it look like the
filtering as a whole isn't working properly, when actually it is doing
what it was asked to do - it just wasn't asked to do the right thing.
The other is that for the really high-volume tracers e.g. the function
tracer, the volume of filtered events can be so high that it pushes the
unfiltered events out of the ring buffer before they can be read so e.g.
cat'ing the trace file repeatedly shows either no output, or once in
awhile some output but that isn't there the next time you read the
trace, which isn't what you normally expect when reading the trace file.
If you read from the trace_pipe file though, you can catch them before
they disappear.
Changes from v1:
As suggested by Frederic Weisbecker:
- get rid of externs in functions
- added unlikely() to filter_check_discard()
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Before patch:
# tracer: power
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
[ 676.875865889] CSTATE: Going to C1 on cpu 0 for 0.005911463
[ 676.882938805] CSTATE: Going to C1 on cpu 0 for 0.104796532
...
After patch:
# tracer: power
#
# TIMESTAMP STATE EVENT
# | | |
[ 676.875865889] CSTATE: Going to C1 on cpu 0 for 0.005911463
[ 676.882938805] CSTATE: Going to C1 on cpu 0 for 0.104796532
...
v2: Use seq_puts instead of seq_printf
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <49E2E889.5000903@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
BLK_TC_PC events should be treated differently with BLK_TC_FS events.
Before this patch:
# echo 1 > /sys/block/sda/sda1/trace/enable
# echo pc > /sys/block/sda/sda1/trace/act_mask
# echo blk > /debugfs/tracing/current_tracer
# (generate some BLK_TC_PC events)
# cat trace
bash-2184 [000] 1774.275413: 8,7 I N [bash]
bash-2184 [000] 1774.275435: 8,7 D N [bash]
bash-2184 [000] 1774.275540: 8,7 I R [bash]
bash-2184 [000] 1774.275547: 8,7 D R [bash]
ksoftirqd/0-4 [000] 1774.275580: 8,7 C N 0 [0]
bash-2184 [000] 1774.275648: 8,7 I R [bash]
bash-2184 [000] 1774.275653: 8,7 D R [bash]
ksoftirqd/0-4 [000] 1774.275682: 8,7 C N 0 [0]
bash-2184 [000] 1774.275739: 8,7 I R [bash]
bash-2184 [000] 1774.275744: 8,7 D R [bash]
ksoftirqd/0-4 [000] 1774.275771: 8,7 C N 0 [0]
bash-2184 [000] 1774.275804: 8,7 I R [bash]
bash-2184 [000] 1774.275808: 8,7 D R [bash]
ksoftirqd/0-4 [000] 1774.275836: 8,7 C N 0 [0]
After this patch:
# cat trace
bash-2263 [000] 366.782149: 8,7 I N 0 (00 ..) [bash]
bash-2263 [000] 366.782323: 8,7 D N 0 (00 ..) [bash]
bash-2263 [000] 366.782557: 8,7 I R 8 (25 00 ..) [bash]
bash-2263 [000] 366.782560: 8,7 D R 8 (25 00 ..) [bash]
ksoftirqd/0-4 [000] 366.782582: 8,7 C N (25 00 ..) [0]
bash-2263 [000] 366.782648: 8,7 I R 8 (5a 00 3f 00) [bash]
bash-2263 [000] 366.782650: 8,7 D R 8 (5a 00 3f 00) [bash]
ksoftirqd/0-4 [000] 366.782669: 8,7 C N (5a 00 3f 00) [0]
bash-2263 [000] 366.782710: 8,7 I R 8 (5a 00 08 00) [bash]
bash-2263 [000] 366.782713: 8,7 D R 8 (5a 00 08 00) [bash]
ksoftirqd/0-4 [000] 366.782730: 8,7 C N (5a 00 08 00) [0]
bash-2263 [000] 366.783375: 8,7 I R 36 (5a 00 08 00) [bash]
bash-2263 [000] 366.783379: 8,7 D R 36 (5a 00 08 00) [bash]
ksoftirqd/0-4 [000] 366.783404: 8,7 C N (5a 00 08 00) [0]
This is what we do with PC events in user-space blktrace.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49D32387.9040106@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Not all events are pc (packet command) events. An event is a pc
event only if it has BLK_TC_PC bit set.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49D3236D.3090705@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: refactor code for future changes
Current kmemtrace.h is used both as header file of kmemtrace and kmem's
tracepoints definition.
Tracepoints' definition file may be used by other code, and should only have
definition of tracepoint.
We can separate include/trace/kmemtrace.h into 2 files:
include/linux/kmemtrace.h: header file for kmemtrace
include/trace/kmem.h: definition of kmem tracepoints
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Acked-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <49DEE68A.5040902@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
- propagate return value of filter_add_pred() to the user
- return -ENOSPC but not -ENOMEM or -EINVAL when the filter array
is full
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49E04CF0.3010105@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make sure messages from user space are NIL-terminated strings,
otherwise we could dump random memory while reading filter file.
Try this:
# echo 'parent_comm ==' > events/sched/sched_process_fork/filter
# cat events/sched/sched_process_fork/filter
parent_comm == �
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49E04C32.6060508@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When moving documents to Documentation/trace/, I forgot to
grep Kconfig to find out those references.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Pekka Paalanen <pq@iki.fi>
Cc: eduard.munteanu@linux360.ro
LKML-Reference: <49DE97EF.7080208@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge reason: pick up both v2.6.30-rc1 [which includes tracing/urgent fixes]
and pick up the current lineup of tracing/urgent fixes as well
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I got these from strace:
splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288
splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288
splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288
splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 16384
splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192
splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192
splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192
I wanted to splice_read 4096 bytes, but it returns 8192 or larger.
It is because the return value of tracing_buffers_splice_read()
does not include "zero out any left over data" bytes.
But tracing_buffers_read() includes these bytes, we make them
consistent.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <49D46674.9030804@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Cleanup
These two lines:
if (unlikely(*ppos))
return -ESPIPE;
in tracing_buffers_splice_read() are not needed, VFS layer
has disabled seek(2).
We remove these two lines, and then we can update file->f_pos.
And tracing_buffers_read() updates file->f_pos, this fix
make tracing_buffers_splice_read() updates file->f_pos too.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <49D46670.4010503@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Cleanup
Sometimes, we open trace_pipe_raw, but we don't read(2) it,
we just splice(2) it, thus, the page is not used.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <49D4666B.4010608@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: disable pread()
We set tracing_buffers_fops.llseek to no_llseek,
but we can still perform pread() to read this file.
That is not expected.
This fix uses nonseekable_open() to disable it.
tracing_buffers_fops.llseek is still set to no_llseek,
it mark this file is a "non-seekable device" and is used by
sys_splice(). See also do_splice() or manual of splice(2):
ERRORS
EINVAL Target file system doesn't support splicing;
neither of the descriptors refers to a pipe;
or offset given for non-seekable device.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <49D46668.8030806@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix kfree crash with non-standard act_mask string
If passing a string with leading white spaces to strstrip(),
the returned ptr != the original ptr.
This bug was introduced by me.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49DD694C.8020902@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix build warnings and possibe compat misbehavior on IA64
Building a kernel on ia64 might trigger these ugly build warnings:
CC arch/ia64/ia32/sys_ia32.o
In file included from arch/ia64/ia32/sys_ia32.c:55:
arch/ia64/ia32/ia32priv.h:290:1: warning: "elf_check_arch" redefined
In file included from include/linux/elf.h:7,
from include/linux/module.h:14,
from include/linux/ftrace.h:8,
from include/linux/syscalls.h:68,
from arch/ia64/ia32/sys_ia32.c:18:
arch/ia64/include/asm/elf.h:19:1: warning: this is the location of the previous definition
[...]
sys_ia32.c includes linux/syscalls.h which in turn includes linux/ftrace.h
to import the syscalls tracing prototypes.
But including ftrace.h can pull too much things for a low level file,
especially on ia64 where the ia32 private headers conflict with higher
level headers.
Now we isolate the syscall tracing headers in their own lightweight file.
Reported-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jason Baron <jbaron@redhat.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Michael Davidson <md@google.com>
LKML-Reference: <20090408184058.GB6017@nowhere>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=y
branch tracer: Fix for enabling branch profiling makes sparse unusable
ftrace: Correct a text align for event format output
Update /debug/tracing/README
tracing/ftrace: alloc the started cpumask for the trace file
tracing, x86: remove duplicated #include
ftrace: Add check of sched_stopped for probe_sched_wakeup
function-graph: add proper initialization for init task
tracing/ftrace: fix missing include string.h
tracing: fix incorrect return type of ns2usecs()
tracing: remove CALLER_ADDR2 from wakeup tracer
blktrace: fix pdu_len when tracing packet command requests
blktrace: small cleanup in blk_msg_write()
blktrace: NUL-terminate user space messages
tracing: move scripts/trace/power.pl to scripts/tracing/power.pl
Unify sched_switch and sched_wakeup's action to following logic:
Do record_cmdline when start_cmdline_record() is called.
Start tracing events when the tracer is started.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
LKML-Reference: <49D1C596.5050203@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Impact: cleanup
The variable ftrace_graph_active is only modified under the
ftrace_lock mutex, thus an atomic is not necessary for modification.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Impact: cleanup
Most of the tracing files creation follow the same pattern:
ret = debugfs_create_file(...)
if (!ret)
pr_warning("Couldn't create ... entry\n")
Unify it!
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1238109938-11840-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Impact: cleanup
Use USEC_PER_SEC and NSEC_PER_SEC instead of 1000000 and 1000000000.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <49CC7870.9000309@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Some of the tracers have been renamed, which was not updated in the in-kernel
run-time README file. Update it.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
LKML-Reference: <200903231158.32151.knikanth@suse.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix a crash while cat trace file
Currently we are using a cpumask to remind each cpu where a
trace occured. It lets us notice the user that a cpu just had
its first trace.
But on latest -tip we have the following crash once we cat the trace
file:
IP: [<c0270c4a>] print_trace_fmt+0x45/0xe7
*pde = 00000000
Oops: 0000 [#1] PREEMPT SMP
last sysfs file: /sys/class/net/eth0/carrier
Pid: 3897, comm: cat Not tainted (2.6.29-tip-02825-g0f22972-dirty #81)
EIP: 0060:[<c0270c4a>] EFLAGS: 00010297 CPU: 0
EIP is at print_trace_fmt+0x45/0xe7
EAX: 00000000 EBX: 00000000 ECX: c12d9e98 EDX: ccdb7010
ESI: d31f4000 EDI: 00322401 EBP: d31f3f10 ESP: d31f3efc
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process cat (pid: 3897, ti=d31f2000 task=d3b3cf20 task.ti=d31f2000)
Stack:
d31f4080 ccdb7010 d31f4000 d691fe70 ccdb7010 d31f3f24 c0270e5c d31f4000
d691fe70 d31f4000 d31f3f34 c02718e8 c12d9e98 d691fe70 d31f3f70 c02bfc33
00001000 09130000 d3b46e00 d691fe98 00000000 00000079 00000001 00000000
Call Trace:
[<c0270e5c>] ? print_trace_line+0x170/0x17c
[<c02718e8>] ? s_show+0xa7/0xbd
[<c02bfc33>] ? seq_read+0x24a/0x327
[<c02bf9e9>] ? seq_read+0x0/0x327
[<c02ab18b>] ? vfs_read+0x86/0xe1
[<c02ab289>] ? sys_read+0x40/0x65
[<c0202d8f>] ? sysenter_do_call+0x12/0x3c
Code: 00 00 00 89 45 ec f7 c7 00 20 00 00 89 55 f0 74 4e f6 86 98 10 00 00 02 74 45 8b 86 8c 10 00 00 8b 9e a8 10 00 00 e8 52 f3 ff ff <0f> a3 03 19 c0 85 c0 75 2b 8b 86 8c 10 00 00 8b 9e a8 10 00 00
EIP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 SS:ESP 0068:d31f3efc
CR2: 0000000000000000
---[ end trace aa9cf38e5ebed9dd ]---
This is because we alloc the iter->started cpumask on tracing_pipe_open but
not on tracing_open.
It hadn't been noticed until now because we need to have ring buffer overruns
to activate the starting of cpu buffer detection.
Also, we need a check to not print the messagge for the first trace on the file.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1238619188-6109-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The wakeup tracing in sched_switch does not stop when a user
disables tracing. This is because the probe_sched_wakeup() is missing
the check to prevent the wakeup from being traced.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
LKML-Reference: <49D1C543.3010307@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Building a kernel with tracing can raise the following warning on
tip/master:
kernel/trace/trace.c:1249: error: implicit declaration of function 'vbin_printf'
We are missing an include to string.h
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1238160130-7437-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix time output bug in 32bits system
ns2usecs() returns 'long', it's incorrect.
(In i386)
...
<idle>-0 [000] 521.442100: _spin_lock <-tick_do_update_jiffies64
<idle>-0 [000] 521.442101: do_timer <-tick_do_update_jiffies64
<idle>-0 [000] 521.442102: update_wall_time <-do_timer
<idle>-0 [000] 521.442102: update_xtime_cache <-update_wall_time
....
(It always print the time less than 2200 seconds besides ...)
Because 'long' is 32bits in i386. ( (1<<31) useconds is about 2200 seconds)
...
<idle>-0 [001] 4154502640.134759: rcu_bh_qsctr_inc <-__do_softirq
<idle>-0 [001] 4154502640.134760: _local_bh_enable <-__do_softirq
<idle>-0 [001] 4154502640.134761: idle_cpu <-irq_exit
...
(very large value)
Because 'long' is a signed type and it is 32bits in i386.
Changes in v2:
return 'unsigned long long' instead of 'cycle_t'
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <49D05D10.4030009@cn.fujitsu.com>
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Maneesh Soni was getting a crash when running the wakeup tracer.
We debugged it down to the recording of the function with the
CALLER_ADDR2 macro. This is used to get the location of the caller
to schedule.
But the problem comes when schedule is called by assmebly. In the case
that Maneesh had, retint_careful would call schedule. But retint_careful
does not set up a proper frame pointer. CALLER_ADDR2 is defined as
__builtin_return_address(2). This produces the following assembly in
the wakeup tracer code.
mov 0x0(%rbp),%rcx <--- get the frame pointer of the caller
mov %r14d,%r8d
mov 0xf2de8e(%rip),%rdi
mov 0x8(%rcx),%rsi <-- this is __builtin_return_address(1)
mov 0x28(%rdi,%rax,8),%rbx
mov (%rcx),%rax <-- get the frame pointer of the caller's caller
mov %r12,%rcx
mov 0x8(%rax),%rdx <-- this is __builtin_return_address(2)
At the reading of 0x8(%rax) Maneesh's machine would take a fault.
The reason is that retint_careful did not set up the return address
and the content of %rax here was zero.
To verify this, I sent Maneesh a patch to create a frame pointer
in retint_careful. He ran the test again but this time he would take
the same type of fault from sysret_careful. The retint_careful was no
longer an issue, but there are other callers that still have issues.
Instead of adding frame pointers for all callers to schedule (in possibly
all archs), it is much safer to simply not use CALLER_ADDR2. This
loses out on knowing what called schedule, but the function tracer
will help there if needed.
Reported-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge reason: this used to be a tracing/blktrace-v2 devel topic still
cooking during the merge window - has propagated to fixes
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The hw-branch-tracer uses debug store functions from an on_each_cpu()
context, which is simply wrong since the functions may sleep.
Add _noirq variants for most functions, which may be called with
interrupts disabled.
Separate per-cpu and per-task tracing and allow per-cpu tracing to be
controlled from any cpu.
Make the hw-branch-tracer use the new debug store interface, synchronize
with hotplug cpu event using get/put_online_cpus(), and remove the
unnecessary spinlock.
Make the ptrace bts and the ds selftest code use the new interface.
Defer the ds selftest.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Cc: roland@redhat.com
Cc: eranian@googlemail.com
Cc: oleg@redhat.com
Cc: juan.villacis@intel.com
Cc: ak@linux.jf.intel.com
LKML-Reference: <20090403144555.658136000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'kmemtrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
kmemtrace: trace kfree() calls with NULL or zero-length objects
kmemtrace: small cleanups
kmemtrace: restore original tracing data binary format, improve ABI
kmemtrace: kmemtrace_alloc() must fill type_id
kmemtrace: use tracepoints
kmemtrace, rcu: don't include unnecessary headers, allow kmemtrace w/ tracepoints
kmemtrace, rcu: fix rcupreempt.c data structure dependencies
kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies
kmemtrace, rcu: fix linux/rcutree.h and linux/rcuclassic.h dependencies
kmemtrace, mm: fix slab.h dependency problem in mm/failslab.c
kmemtrace, kbuild: fix slab.h dependency problem in lib/decompress_unlzma.c
kmemtrace, kbuild: fix slab.h dependency problem in lib/decompress_bunzip2.c
kmemtrace, kbuild: fix slab.h dependency problem in lib/decompress_inflate.c
kmemtrace, squashfs: fix slab.h dependency problem in squasfs
kmemtrace, befs: fix slab.h dependency problem
kmemtrace, security: fix linux/key.h header file dependencies
kmemtrace, fs: fix linux/fdtable.h header file dependencies
kmemtrace, fs: uninline simple_transaction_set()
kmemtrace, fs, security: move alloc_secdata() and free_secdata() to linux/security.h
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits)
tracing, net: fix net tree and tracing tree merge interaction
tracing, powerpc: fix powerpc tree and tracing tree interaction
ring-buffer: do not remove reader page from list on ring buffer free
function-graph: allow unregistering twice
trace: make argument 'mem' of trace_seq_putmem() const
tracing: add missing 'extern' keywords to trace_output.h
tracing: provide trace_seq_reserve()
blktrace: print out BLK_TN_MESSAGE properly
blktrace: extract duplidate code
blktrace: fix memory leak when freeing struct blk_io_trace
blktrace: fix blk_probes_ref chaos
blktrace: make classic output more classic
blktrace: fix off-by-one bug
blktrace: fix the original blktrace
blktrace: fix a race when creating blk_tree_root in debugfs
blktrace: fix timestamp in binary output
tracing, Text Edit Lock: cleanup
tracing: filter fix for TRACE_EVENT_FORMAT events
ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
x86: kretprobe-booster interrupt emulation code fix
...
Fix up trivial conflicts in
arch/parisc/include/asm/ftrace.h
include/linux/memory.h
kernel/extable.c
kernel/module.c
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (28 commits)
trivial: Update my email address
trivial: NULL noise: drivers/mtd/tests/mtd_*test.c
trivial: NULL noise: drivers/media/dvb/frontends/drx397xD_fw.h
trivial: Fix misspelling of "Celsius".
trivial: remove unused variable 'path' in alloc_file()
trivial: fix a pdlfush -> pdflush typo in comment
trivial: jbd header comment typo fix for JBD_PARANOID_IOFAIL
trivial: wusb: Storage class should be before const qualifier
trivial: drivers/char/bsr.c: Storage class should be before const qualifier
trivial: h8300: Storage class should be before const qualifier
trivial: fix where cgroup documentation is not correctly referred to
trivial: Give the right path in Documentation example
trivial: MTD: remove EOL from MODULE_DESCRIPTION
trivial: Fix typo in bio_split()'s documentation
trivial: PWM: fix of #endif comment
trivial: fix typos/grammar errors in Kconfig texts
trivial: Fix misspelling of firmware
trivial: cgroups: documentation typo and spelling corrections
trivial: Update contact info for Jochen Hein
trivial: fix typo "resgister" -> "register"
...
Impact: output all of packet commands - not just the first 4 / 8 bytes
Since commit d7e3c3249e ("block: add
large command support"), struct request->cmd has been changed from
unsinged char cmd[BLK_MAX_CDB] to unsigned char *cmd.
v1 -> v2: by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
- make sure rq->cmd_len is always intialized, and then we can use
rq->cmd_len instead of BLK_MAX_CDB.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49D4507E.2060602@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix corrupted blkparse output
Make sure messages from user space are NUL-terminated strings,
otherwise we could dump random memory to the block trace file.
Additionally, I've limited the message to BLK_TN_MAX_MSG-1
characters, because the last character would be stripped by
vscnprintf anyway.
Signed-off-by: Carl Henrik Lunde <chlunde@ping.uio.no>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "Alan D. Brunelle" <alan.brunelle@hp.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20090403122714.GT5178@kernel.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When kmemtrace was ported to ftrace, the marker strings were taken as
an indication of how the traced data was being exposed to the userspace.
However, the actual format had been binary, not text.
This restores the original binary format, while also adding an origin CPU
field (since ftrace doesn't expose the data per-CPU to userspace), and
re-adding the timestamp field. It also drops arch-independent field
sizing where it didn't make sense, so pointers won't always be 64 bits
wide like they used to.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
LKML-Reference: <161be9ca8a27b432c4a6ab79f47788c4521652ae.1237813499.git.eduard.munteanu@linux360.ro>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix trace output
kmemtrace_alloc() was not filling type_id, which allowed garbage to make
it into tracing data.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
LKML-Reference: <284dba2732a144849d5aa82258fe0de2ad8dcb0b.1237813499.git.eduard.munteanu@linux360.ro>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kmemtrace now uses tracepoints instead of markers. We no longer need to
use format specifiers to pass arguments.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
[ folded: Use the new TP_PROTO and TP_ARGS to fix the build. ]
[ folded: fix build when CONFIG_KMEMTRACE is disabled. ]
[ folded: define tracepoints when CONFIG_TRACEPOINTS is enabled. ]
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <ae61c0f37156db8ec8dc0d5778018edde60a92e3.1237813499.git.eduard.munteanu@linux360.ro>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: prevent possible memory leak
The reader page of the ring buffer is special. Although it points
into the ring buffer, it is not part of the actual buffer. It is
a page used by the reader to swap with a page in the ring buffer.
Once the swap is made, the new reader page is again outside the
buffer.
Even though the reader page points into the buffer, it is really
pointing to residual data. Note, this data is used by the reader.
reader page
|
v
(prev) +---+ (next)
+----------| |----------+
| +---+ |
v v
+---+ +---+ +---+
-->| |------->| |------->| |--->
<--| |<-------| |<-------| |<---
+---+ +---+ +---+
^ ^ ^
\ | /
------- Buffer---------
If we perform a list_del_init() on the reader page we will actually remove
the last page the reader swapped with and not the reader page itself.
This will cause that page to not be freed, and thus is a memory leak.
Luckily, the only user of the ring buffer so far is ftrace. And ftrace
will not free its ring buffer after it allocates it. There is no current
possible memory leak. But once there are other users, or if ftrace
dynamically creates and frees its ring buffer, then this would be a
memory leak.
This patch fixes the leak for future cases.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix to permanent disabling of function graph tracer
There should be nothing to prevent a tracer from unregistering a
function graph callback more than once. This can simplify error paths.
But currently, the counter does not account for mulitple unregistering
of the function graph callback. If it happens, the function graph
tracer will be permanently disabled.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix build warning
I passed a const value to trace_seq_putmem(), and I got compile warning.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Many declarations within trace_output.h are missing the 'extern' keyword
in an inconsistent manner. This adds 'extern' where it should be.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
trace_seq_reserve() allows a caller to reserve space in a trace_seq and
write directly into it. This makes it easier to export binary data to
userspace via the tracing interface, by simply filling in a struct.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
blk_trace_event_print() and blk_tracer_print_line() share most of the code.
text data bss dec hex filename
8605 393 12 9010 2332 kernel/trace/blktrace.o.orig
text data bss dec hex filename
8555 393 12 8960 2300 kernel/trace/blktrace.o
This patch also prepares for the next patch, that prints out BLK_TN_MESSAGE.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix mixed ioctl and ftrace-plugin blktrace use memory leak
When mixing the use of ioctl-based blktrace and ftrace-based blktrace,
we can leak memory in this way:
# btrace /dev/sda > /dev/null &
# echo 0 > /sys/block/sda/sda1/trace/enable
now we leak bt->dropped_file, bt->msg_file, bt->rchan...
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix mixed ioctl and ftrace-plugin blktrace use refcount bugs
ioctl-based blktrace allocates bt and registers tracepoints when
ioctl(BLKTRACESETUP), and do all cleanups when ioctl(BLKTRACETEARDOWN).
while ftrace-based blktrace allocates/frees bt when:
# echo 1/0 > /sys/block/sda/sda1/trace/enable
and registers/unregisters tracepoints when:
# echo blk/nop > /debugfs/tracing/current_tracer
or
# echo 1/0 > /debugfs/tracing/tracing_enable
The separatation of allocation and registeration causes 2 problems:
1. current user-space blktrace still calls ioctl(TEARDOWN) when
ioctl(SETUP) failed:
# echo 1 > /sys/block/sda/sda1/trace/enable
# blktrace /dev/sda
BLKTRACESETUP: Device or resource busy
^C
and now blk_probes_ref == -1
2. Another way to make blk_probes_ref == -1:
# plugin sdb && mount sdb1
# echo 1 > /sys/block/sdb/sdb1/trace/enable
# remove sdb
This patch does the allocation and registeration when writing
sdaX/trace/enable.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
'what' is used as the index of array what2act, so it can't >= the array size.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently the original blktrace, which is using relay and is used via
ioctl, is broken. You can use ftrace to see the output of blktrace,
but user-space blktrace is unusable.
It's broken by "blktrace: add ftrace plugin"
(c71a896154)
- if (unlikely(bt->trace_state != Blktrace_running))
+ if (unlikely(bt->trace_state != Blktrace_running || !blk_tracer_enabled))
return;
With this patch, both ioctl and ftrace can be used, but of course you
can't use both of them at the same time.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
