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2009-06-24tracing/events: Don't increment @pos in s_start()Li Zefan
While testing syscall tracepoints posted by Jason, I found 3 entries were missing when reading available_events. The output size of available_events is < 4 pages, which means we lost 1 entry per page. The cause is, it's wrong to increment @pos in s_start(). Actually there's another bug here -- reading avaiable_events/set_events can race with module unload: # cat available_events | s_start() | s_stop() | | # rmmod foo.ko s_start() | call = list_entry(m->private) | @call might be freed and accessing it will lead to crash. Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A4186DD.6090405@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-09tracing: add protection around module events unloadSteven Rostedt
When reading the trace buffer, there is a race that when a module is unloaded it removes events that is stilled referenced in the buffers. This patch adds the protection around the unloading of the events from modules and the reading of the trace buffers. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-26ftrace: clean up of using ftrace_event_enable_disable()Zhaolei
Always use ftrace_event_enable_disable() to enable/disable an event so that we can factorize out the event toggling code. [ Impact: factorize and cleanup event tracing code ] Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26ftrace: Add task_comm support for trace_eventZhaolei
If we enable a trace event alone without any tracer running (such as function tracer, sched switch tracer, etc...) it can't output enough task command information. We need to use the tracing_{start/stop}_cmdline_record() helpers which are designed to keep track of cmdlines for any tasks that were scheduled during the tracing. Before this patch: # echo 1 > debugfs/tracing/events/sched/sched_switch/enable # cat debugfs/tracing/trace # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <...>-2289 [000] 526276.724790: sched_switch: task bash:2289 [120] ==> sshd:2287 [120] <...>-2287 [000] 526276.725231: sched_switch: task sshd:2287 [120] ==> bash:2289 [120] <...>-2289 [000] 526276.725452: sched_switch: task bash:2289 [120] ==> sshd:2287 [120] <...>-2287 [000] 526276.727181: sched_switch: task sshd:2287 [120] ==> swapper:0 [140] <idle>-0 [000] 526277.032734: sched_switch: task swapper:0 [140] ==> events/0:5 [115] <...>-5 [000] 526277.032782: sched_switch: task events/0:5 [115] ==> swapper:0 [140] ... After this patch: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | bash-2269 [000] 527347.989229: sched_switch: task bash:2269 [120] ==> sshd:2267 [120] sshd-2267 [000] 527347.990960: sched_switch: task sshd:2267 [120] ==> bash:2269 [120] bash-2269 [000] 527347.991143: sched_switch: task bash:2269 [120] ==> sshd:2267 [120] sshd-2267 [000] 527347.992959: sched_switch: task sshd:2267 [120] ==> swapper:0 [140] <idle>-0 [000] 527348.531989: sched_switch: task swapper:0 [140] ==> events/0:5 [115] events/0-5 [000] 527348.532115: sched_switch: task events/0:5 [115] ==> swapper:0 [140] ... Changelog: v1->v2: Update Kconfig to select CONTEXT_SWITCH_TRACER in ENABLE_EVENT_TRACING v2->v3: v2 can solve problem that was caused by config EVENT_TRACING alone, but when CONFIG_FTRACE is off and CONFIG_TRACING is selected by other config, compile fail happened again. This version solves it. [ Impact: fix incomplete output of event tracing ] Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-20ftrace: fix check for return value of register_module_notifier in ↵Ming Lei
event_trace_init register_module_notifier() returns zero in the success case. So fix the inverted fail case check in trace events modules handler. [ Impact: fix spurious warning on ftrace initialization] Reported-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-08tracing: add trace_set_clr_event to export event enabling functionSteven Rostedt
Other parts of the kernel may need to be able to enable or disable specific events. Especially parts that create trace events. [ Impact: allow enabling of trace events by those that create the event ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-08tracing: initialize return value for __ftrace_set_clr_eventSteven Rostedt
Commit 8f31bfe538ebafac187d2d4465a92e1d9ee6d8c2 tracing/events: clean up for ftrace_set_clr_event() Moved out the code for ftrace_set_clr_event into a helper funciton but did not initialize the return value. As a result, we do not warn about a typo in the echoing of events in set_event. This patch restores the old warning: # echo foobar > set_event -bash: echo: write error: Invalid argument [ Impact: restore warning of invalid entries to set_event ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-08tracing/events: simplify system_enable_read()Li Zefan
A smarter way to figure out the output of an enable file. [ Impact: clean up ] Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A0399A5.2080603@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-08tracing/events: clean up for ftrace_set_clr_event()Li Zefan
Add a helper function __ftrace_set_clr_event(), and replace some ftrace_set_clr_event() calls with this helper, thus we don't need any kstrdup() or kmalloc(). As a side effect, this patch fixes an issue in self tests code, which is similar to the one fixed in commit d6bf81ef0f7474434c2a049e8bf3c9146a14dd96 ("tracing: append ":*" to internal setting of system events") It's a small issue and won't cause any bug in fact, but we should do things right anyway. [ Impact: prevent spurious event-enabling in tracing self-tests ] Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A03998E.3020503@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-07tracing: append ":*" to internal setting of system eventsSteven Rostedt
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>
2009-05-06tracing: add hierarchical enabling of eventsSteven Rostedt
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>
2009-05-06tracing: reset ring buffer when removing modules with eventsSteven Rostedt
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>
2009-05-06tracing/events: fix concurrent access to ftrace_events listLi Zefan
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>
2009-05-06tracing/events: fix memory leak when unloading moduleLi Zefan
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>
2009-04-29tracing/filters: a better event parserTom Zanussi
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>
2009-04-29tracing/filters: distinguish between signed and unsigned fieldsTom Zanussi
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>
2009-04-29tracing/filters: move preds into event_filter objectTom Zanussi
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>
2009-04-26tracing/events: make modules have their own file_operations structureSteven Rostedt
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>
2009-04-23tracing: add size checks for exported ftrace internal structuresSteven Rostedt
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>
2009-04-23tracing: increase size of number of possible eventsSteven Rostedt
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>
2009-04-22tracing/events: make struct trace_entry->type to be int typeLi Zefan
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>
2009-04-21tracing/filters: don't remove old filters when failed to write subsys->filterLi Zefan
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>
2009-04-20tracing: use nowakeup version of commit for function event trace testsSteven Rostedt
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>
2009-04-20tracing/events: call the correct event trace selftest init functionSteven Rostedt
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>
2009-04-17tracing/filters: add filter_mutex to protect filter predicatesTom Zanussi
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>
2009-04-17tracing/events: perform function tracing in event selftestsSteven Rostedt
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>
2009-04-17tracing/events/ring-buffer: expose format of ring buffer headers to usersSteven Rostedt
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>
2009-04-17tracing/events: add startup tests for eventsSteven Rostedt
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>
2009-04-14tracing/events: fix compile for modules disabledSteven Rostedt
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>
2009-04-14tracing/events: add support for modules to TRACE_EVENTSteven Rostedt
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>
2009-04-14tracing/events: add export symbols for trace events in modulesSteven Rostedt
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>
2009-04-14tracing/events: convert event call sites to use a link listSteven Rostedt
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>
2009-04-14tracing/filters: allow on-the-fly filter switchingTom Zanussi
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>
2009-04-14Merge branch 'linus' into tracing/coreIngo Molnar
Merge reason: merge latest tracing fixes to avoid conflicts in kernel/trace/trace_events_filter.c with upcoming change Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-14tracing/filters: add run-time field descriptions to TRACE_EVENT_FORMAT eventsTom Zanussi
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>
2009-04-12tracing/filters: return proper error code when writing filter fileLi Zefan
- 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>
2009-04-12tracing/filters: NIL-terminate user input filterLi Zefan
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>
2009-03-26tracing: filter fix for TRACE_EVENT_FORMAT eventsTom Zanussi
Impact: fix crash (hang) when using TRACE_EVENT_FORMAT filter files filters are only hooked up to the tracepoint events defined using TRACE_EVENT but not the tracers that use TRACE_EVENT_FORMAT, such as ftrace. Do not display the filter files at all for TRACE_EVENT_FORMAT events for the time being. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237878882.8339.61.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-24tracing/filters: use trace_seq_printf() to print filtersTom Zanussi
Impact: cleanup Instead of just using the trace_seq buffer to print the filters, use trace_seq_printf() as it was intended to be used. Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237878871.8339.59.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-24tracing/filters: free pred when clearing filtersTom Zanussi
Impact: fix (small) per trace filter modification memory leak Free the current pred when clearing the filters via the filter files. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237878851.8339.58.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-23tracing/filters: clean up filter_add_subsystem_pred()Tom Zanussi
Impact: cleanup, memory leak fix This patch cleans up filter_add_subsystem_pred(): - searches for the field before creating a copy of the pred - fixes memory leak in the case a predicate isn't applied - if -ENOMEM, makes sure there's no longer a reference to the pred so the caller can free the half-finished filter - changes the confusing i == MAX_FILTER_PRED - 1 comparison previously remarked upon This affects only per-subsystem event filtering. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237796808.7527.40.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-23tracing/events: make the filter files writableFrederic Weisbecker
We need the filter files to be writable, the current filter file permissions are only set readable. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <1237759847-21025-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-22tracing: add run-time field descriptions for event filtering, kfree fixIngo Molnar
Impact: fix potential kfree of random data in (rare) failure path Zero-initialize the field structure. Reported-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <1237710639.7703.46.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-22tracing: add per-subsystem filteringTom Zanussi
This patch adds per-subsystem filtering to the event tracing subsystem. It adds a 'filter' debugfs file to each subsystem directory. This file can be written to to set filters; reading from it will display the current set of filters set for that subsystem. Basically what it does is propagate the filter down to each event contained in the subsystem. If a particular event doesn't have a field with the name specified in the filter, it simply doesn't get set for that event. You can verify whether or not the filter was set for a particular event by looking at the filter file for that event. As with per-event filters, compound expressions are supported, echoing '0' to the subsystem's filter file clears all filters in the subsystem, etc. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237710677.7703.49.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-22tracing: add per-event filteringTom Zanussi
This patch adds per-event filtering to the event tracing subsystem. It adds a 'filter' debugfs file to each event directory. This file can be written to to set filters; reading from it will display the current set of filters set for that event. Basically, any field listed in the 'format' file for an event can be filtered on (including strings, but not yet other array types) using either matching ('==') or non-matching ('!=') 'predicates'. A 'predicate' can be either a single expression: # echo pid != 0 > filter # cat filter pid != 0 or a compound expression of up to 8 sub-expressions combined using '&&' or '||': # echo comm == Xorg > filter # echo "&& sig != 29" > filter # cat filter comm == Xorg && sig != 29 Only events having field values matching an expression will be available in the trace output; non-matching events are discarded. Note that a compound expression is built up by echoing each sub-expression separately - it's not the most efficient way to do things, but it keeps the parser simple and assumes that compound expressions will be relatively uncommon. In any case, a subsequent patch introducing a way to set filters for entire subsystems should mitigate any need to do this for lots of events. Setting a filter without an '&&' or '||' clears the previous filter completely and sets the filter to the new expression: # cat filter comm == Xorg && sig != 29 # echo comm != Xorg # cat filter comm != Xorg To clear a filter, echo 0 to the filter file: # echo 0 > filter # cat filter none The limit of 8 predicates for a compound expression is arbitrary - for efficiency, it's implemented as an array of pointers to predicates, and 8 seemed more than enough for any filter... Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237710665.7703.48.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-22tracing: add run-time field descriptions for event filteringTom Zanussi
This patch makes the field descriptions defined for event tracing available at run-time, for the event-filtering mechanism introduced in a subsequent patch. The common event fields are prepended with 'common_' in the format display, allowing them to be distinguished from the other fields that might internally have same name and can therefore be unambiguously used in filters. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237710639.7703.46.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-20ftrace: event profile hooksPeter Zijlstra
Impact: new tracing infrastructure feature Provide infrastructure to generate software perf counter events from tracepoints. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090319194233.557364871@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-20ftrace: provide an id file for each eventPeter Zijlstra
Since not every event has a format file to read the id from, expose it explicitly in a separate file. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090319194233.372534033@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-17tracing: fix leak in event_format_read()Tom Zanussi
Impact: fix memory leak If event_format_read() exits early due to nonzero ppos, the previous kmalloc doesn't get freed - might as well do the check before the kmalloc and avoid the problem. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237270859.8033.141.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-12tracing: have event_trace_printk use static tracerSteven Rostedt
Impact: speed up on event tracing The event_trace_printk is currently a wrapper function that calls trace_vprintk. Because it uses a variable for the fmt it misses out on the optimization of using the binary printk. This patch makes event_trace_printk into a macro wrapper to use the fmt as the same as the trace_printks. Signed-off-by: Steven Rostedt <srostedt@redhat.com>