This patch fixes a bug exhibited by the following scenario:
1. fd1 = perf_event_open with attr.config = ID1
2. attach bpf program prog1 to fd1
3. fd2 = perf_event_open with attr.config = ID1
<this will be successful>
4. user program closes fd2 and prog1 is detached from the tracepoint.
5. user program with fd1 does not work properly as tracepoint
no output any more.
The issue happens at step 4. Multiple perf_event_open can be called
successfully, but only one bpf prog pointer in the tp_event. In the
current logic, any fd release for the same tp_event will free
the tp_event->prog.
The fix is to free tp_event->prog only when the closing fd
corresponds to the one which registered the program.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull tracing updates from Steven Rostedt:
"Nothing new in development for this release. These are mostly fixes
that were found during development of changes for the next merge
window and fixes that were sent to me late in the last cycle"
* tag 'trace-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Apply trace_clock changes to instance max buffer
tracing: Fix clear of RECORDED_TGID flag when disabling trace event
tracing: Add barrier to trace_printk() buffer nesting modification
ftrace: Fix memleak when unregistering dynamic ops when tracing disabled
ftrace: Fix selftest goto location on error
ftrace: Zero out ftrace hashes when a module is removed
tracing: Only have rmmod clear buffers that its events were active in
ftrace: Fix debug preempt config name in stack_tracer_{en,dis}able
Currently, when a module event is enabled, when that module is removed, it
clears all ring buffers. This is to prevent another module from being loaded
and having one of its trace event IDs from reusing a trace event ID of the
removed module. This could cause undesirable effects as the trace event of
the new module would be using its own processing algorithms to process raw
data of another event. To prevent this, when a module is loaded, if any of
its events have been used (signified by the WAS_ENABLED event call flag,
which is never cleared), all ring buffers are cleared, just in case any one
of them contains event data of the removed event.
The problem is, there's no reason to clear all ring buffers if only one (or
less than all of them) uses one of the events. Instead, only clear the ring
buffers that recorded the events of a module that is being removed.
To do this, instead of keeping the WAS_ENABLED flag with the trace event
call, move it to the per instance (per ring buffer) event file descriptor.
The event file descriptor maps each event to a separate ring buffer
instance. Then when the module is removed, only the ring buffers that
activated one of the module's events get cleared. The rest are not touched.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When running perf on the ftrace:function tracepoint, there is a bug
which can be reproduced by:
perf record -e ftrace:function -a sleep 20 &
perf record -e ftrace:function ls
perf script
ls 10304 [005] 171.853235: ftrace:function:
perf_output_begin
ls 10304 [005] 171.853237: ftrace:function:
perf_output_begin
ls 10304 [005] 171.853239: ftrace:function:
task_tgid_nr_ns
ls 10304 [005] 171.853240: ftrace:function:
task_tgid_nr_ns
ls 10304 [005] 171.853242: ftrace:function:
__task_pid_nr_ns
ls 10304 [005] 171.853244: ftrace:function:
__task_pid_nr_ns
We can see that all the function traces are doubled.
The problem is caused by the inconsistency of the register
function perf_ftrace_event_register() with the probe function
perf_ftrace_function_call(). The former registers one probe
for every perf_event. And the latter handles all perf_events
on the current cpu. So when two perf_events on the current cpu,
the traces of them will be doubled.
So this patch adds an extra parameter "event" for perf_tp_event,
only send sample data to this event when it's not NULL.
Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: alexander.shishkin@linux.intel.com
Cc: huawei.libin@huawei.com
Link: http://lkml.kernel.org/r/1503668977-12526-1-git-send-email-zhouchengming1@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Inorder to support recording of tgid, the following changes are made:
* Introduce a new API (tracing_record_taskinfo) to additionally record the tgid
along with the task's comm at the same time. This has has the benefit of not
setting trace_cmdline_save before all the information for a task is saved.
* Add a new API tracing_record_taskinfo_sched_switch to record task information
for 2 tasks at a time (previous and next) and use it from sched_switch probe.
* Preserve the old API (tracing_record_cmdline) and create it as a wrapper
around the new one so that existing callers aren't affected.
* Reuse the existing sched_switch and sched_wakeup probes to record tgid
information and add a new option 'record-tgid' to enable recording of tgid
When record-tgid option isn't enabled to being with, we take care to make sure
that there's isn't memory or runtime overhead.
Link: http://lkml.kernel.org/r/20170627020155.5139-1-joelaf@google.com
Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Tested-by: Michael Sartain <mikesart@gmail.com>
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Currently trace_handle_return() looks like this:
static inline enum print_line_t trace_handle_return(struct trace_seq *s)
{
return trace_seq_has_overflowed(s) ?
TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
}
Where trace_seq_overflowed(s) is:
static inline bool trace_seq_has_overflowed(struct trace_seq *s)
{
return s->full || seq_buf_has_overflowed(&s->seq);
}
And seq_buf_has_overflowed(&s->seq) is:
static inline bool
seq_buf_has_overflowed(struct seq_buf *s)
{
return s->len > s->size;
}
Making trace_handle_return() into:
return (s->full || (s->seq->len > s->seq->size)) ?
TRACE_TYPE_PARTIAL_LINE :
TRACE_TYPE_HANDLED;
One would think this is not an issue to keep as an inline. But because this
is used in the TRACE_EVENT() macro, it is extended for every tracepoint in
the system. Taking a look at a single tracepoint x86_irq_vector (was the
first one I randomly chosen). As trace_handle_return is used in the
TRACE_EVENT() macro of trace_raw_output_##call() we disassemble
trace_raw_output_x86_irq_vector and do a diff:
- is the original
+ is the out-of-line code
I removed identical lines that were different just due to different
addresses.
--- /tmp/irq-vec-orig 2017-03-16 09:12:48.569384851 -0400
+++ /tmp/irq-vec-ool 2017-03-16 09:13:39.378153385 -0400
@@ -6,27 +6,23 @@
53 push %rbx
48 89 fb mov %rdi,%rbx
4c 8b a7 c0 20 00 00 mov 0x20c0(%rdi),%r12
e8 f7 72 13 00 callq ffffffff81155c80 <trace_raw_output_prep>
83 f8 01 cmp $0x1,%eax
74 05 je ffffffff8101e993 <trace_raw_output_x86_irq_vector+0x23>
5b pop %rbx
41 5c pop %r12
5d pop %rbp
c3 retq
41 8b 54 24 08 mov 0x8(%r12),%edx
- 48 8d bb 98 10 00 00 lea 0x1098(%rbx),%rdi
+ 48 81 c3 98 10 00 00 add $0x1098,%rbx
- 48 c7 c6 7b 8a a0 81 mov $0xffffffff81a08a7b,%rsi
+ 48 c7 c6 ab 8a a0 81 mov $0xffffffff81a08aab,%rsi
- e8 c5 85 13 00 callq ffffffff81156f70 <trace_seq_printf>
=== here's the start of the main difference ===
+ 48 89 df mov %rbx,%rdi
+ e8 62 7e 13 00 callq ffffffff81156810 <trace_seq_printf>
- 8b 93 b8 20 00 00 mov 0x20b8(%rbx),%edx
- 31 c0 xor %eax,%eax
- 85 d2 test %edx,%edx
- 75 11 jne ffffffff8101e9c8 <trace_raw_output_x86_irq_vector+0x58>
- 48 8b 83 a8 20 00 00 mov 0x20a8(%rbx),%rax
- 48 39 83 a0 20 00 00 cmp %rax,0x20a0(%rbx)
- 0f 93 c0 setae %al
+ 48 89 df mov %rbx,%rdi
+ e8 4a c5 12 00 callq ffffffff8114af00 <trace_handle_return>
5b pop %rbx
- 0f b6 c0 movzbl %al,%eax
=== end ===
41 5c pop %r12
5d pop %rbp
c3 retq
If you notice, the original has 22 bytes of text more than the out of line
version. As this is for every TRACE_EVENT() defined in the system, this can
become quite large.
text data bss dec hex filename
8690305 5450490 1298432 15439227 eb957b vmlinux-orig
8681725 5450490 1298432 15430647 eb73f7 vmlinux-handle
This change has a total of 8580 bytes in savings.
$ objdump -dr /tmp/vmlinux-orig | grep '^[0-9a-f]* <trace_raw_output' | wc -l
324
That's 324 tracepoints. But this does not include modules (which contain
many more tracepoints). For an allyesconfig build:
$ objdump -dr vmlinux-allyes-orig | grep '^[0-9a-f]* <trace_raw_output' | wc -l
1401
That's 1401 tracepoints giving us:
text data bss dec hex filename
137920629 140221067 53264384 331406080 13c0db00 vmlinux-allyes-orig
137827709 140221067 53264384 331313160 13bf7008 vmlinux-allyes-handle
92920 bytes in savings!!!
Link: http://lkml.kernel.org/r/20170315021431.13107-2-andi@firstfloor.org
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Patch series "DAX tracepoints, mm argument simplification", v4.
This contains both my DAX tracepoint code and Dave Jiang's MM argument
simplifications. Dave's code was written with my tracepoint code as a
baseline, so it seemed simplest to keep them together in a single series.
This patch (of 7):
Add __print_flags_u64() and the helper trace_print_flags_seq_u64() in the
same spirit as __print_symbolic_u64() and trace_print_symbols_seq_u64().
These functions allow us to print symbols associated with flags that are
64 bits wide even on 32 bit machines.
These will be used by the DAX code so that we can print the flags set in a
pfn_t such as PFN_SG_CHAIN, PFN_SG_LAST, PFN_DEV and PFN_MAP.
Without this new function I was getting errors like the following when
compiling for i386:
include/linux/pfn_t.h:13:22: warning: large integer implicitly truncated to unsigned type [-Woverflow]
#define PFN_SG_CHAIN (1ULL << (BITS_PER_LONG_LONG - 1))
^
Link: http://lkml.kernel.org/r/1484085142-2297-2-git-send-email-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Steven suggested to improve trace_print_hex_seq() a bit after commit
2acae0d5b0 ("trace: add variant without spacing in trace_print_hex_seq")
in two ways: i) by adding a kdoc comment for the helper function
itself and ii) by renaming 'spacing' argument into 'concatenate'
to better denote that we don't add spaces between each hex bytes.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
For upcoming tracepoint support for BPF, we want to dump the program's
tag. Format should be similar to __print_hex(), but without spacing.
Add a __print_hex_str() variant for exactly that purpose that reuses
trace_print_hex_seq().
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull tracing updates from Steven Rostedt:
"This includes two new updates for the ftrace infrastructure.
- With the changing of the code for filtering events by pid, from a
list of pids to a bitmask, we can now easily implement following
forks. With a new tracing option "event-fork" which, when set,
will have tasks with pids in set_event_pid, when they fork, to have
their child pids added to set_event_pid and the child will be
traced as well.
Note, if "event-fork" is set and a task with its pid in
set_event_pid exits, its pid will be removed from set_event_pid
- The addition of Tom Zanussi's hist triggers. This includes a very
thorough documentatino on how to use the hist triggers with events.
This introduces a quick and easy way to get histogram data from
events and their fields.
Some other cleanups and updates were added as well. Like Masami
Hiramatsu added test cases for the event trigger and hist triggers.
Also I added a speed up of filtering by using a temp buffer when
filters are set"
* tag 'trace-v4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (45 commits)
tracing: Use temp buffer when filtering events
tracing: Remove TRACE_EVENT_FL_USE_CALL_FILTER logic
tracing: Remove unused function trace_current_buffer_lock_reserve()
tracing: Remove one use of trace_current_buffer_lock_reserve()
tracing: Have trace_buffer_unlock_commit() call the _regs version with NULL
tracing: Remove unused function trace_current_buffer_discard_commit()
tracing: Move trace_buffer_unlock_commit{_regs}() to local header
tracing: Fold filter_check_discard() into its only user
tracing: Make filter_check_discard() local
tracing: Move event_trigger_unlock_commit{_regs}() to local header
tracing: Don't use the address of the buffer array name in copy_from_user
tracing: Handle tracing_map_alloc_elts() error path correctly
tracing: Add check for NULL event field when creating hist field
tracing: checking for NULL instead of IS_ERR()
tracing: Do not inherit event-fork option for instances
tracing: Fix unsigned comparison to zero in hist trigger code
kselftests/ftrace: Add a test for log2 modifier of hist trigger
tracing: Add hist trigger 'log2' modifier
kselftests/ftrace: Add hist trigger testcases
kselftests/ftrace : Add event trigger testcases
...
The functions trace_buffer_unlock_commit() and the _regs() version are only
used within the kernel/trace directory. Move them to the local header and
remove the export as well.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Nothing outside of the tracing directory calls filter_check_discard() or
check_filter_check_discard(). They should not be called by modules. Move
their prototypes into the local tracing header and remove their
EXPORT_SYMBOL() macros.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The functions event_trigger_unlock_commit() and
event_trigger_unlock_commit_regs() are no longer used outside the tracing
system. Move them out of the generic headers and into the local one.
Along with __event_trigger_test_discard() that is only used by them.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
move trace_call_bpf() into helper function to minimize the size
of perf_trace_*() tracepoint handlers.
text data bss dec hex filename
10541679 5526646 2945024 19013349 1221ee5 vmlinux_before
10509422 5526646 2945024 18981092 121a0e4 vmlinux_after
It may seem that perf_fetch_caller_regs() can also be moved,
but that is incorrect, since ip/sp will be wrong.
bpf+tracepoint performance is not affected, since
perf_swevent_put_recursion_context() is now inlined.
export_symbol_gpl can also be dropped.
No measurable change in normal perf tracepoints.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to enable_event/disable_event triggers, these triggers enable
and disable the aggregation of events into maps rather than enabling
and disabling their writing into the trace buffer.
They can be used to automatically start and stop hist triggers based
on a matching filter condition.
If there's a paused hist trigger on system:event, the following would
start it when the filter condition was hit:
# echo enable_hist:system:event [ if filter] > event/trigger
And the following would disable a running system:event hist trigger:
# echo disable_hist:system:event [ if filter] > event/trigger
See Documentation/trace/events.txt for real examples.
Link: http://lkml.kernel.org/r/f812f086e52c8b7c8ad5443487375e03c96a601f.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
'hist' triggers allow users to continually aggregate trace events,
which can then be viewed afterwards by simply reading a 'hist' file
containing the aggregation in a human-readable format.
The basic idea is very simple and boils down to a mechanism whereby
trace events, rather than being exhaustively dumped in raw form and
viewed directly, are automatically 'compressed' into meaningful tables
completely defined by the user.
This is done strictly via single-line command-line commands and
without the aid of any kind of programming language or interpreter.
A surprising number of typical use cases can be accomplished by users
via this simple mechanism. In fact, a large number of the tasks that
users typically do using the more complicated script-based tracing
tools, at least during the initial stages of an investigation, can be
accomplished by simply specifying a set of keys and values to be used
in the creation of a hash table.
The Linux kernel trace event subsystem happens to provide an extensive
list of keys and values ready-made for such a purpose in the form of
the event format files associated with each trace event. By simply
consulting the format file for field names of interest and by plugging
them into the hist trigger command, users can create an endless number
of useful aggregations to help with investigating various properties
of the system. See Documentation/trace/events.txt for examples.
hist triggers are implemented on top of the existing event trigger
infrastructure, and as such are consistent with the existing triggers
from a user's perspective as well.
The basic syntax follows the existing trigger syntax. Users start an
aggregation by writing a 'hist' trigger to the event of interest's
trigger file:
# echo hist:keys=xxx [ if filter] > event/trigger
Once a hist trigger has been set up, by default it continually
aggregates every matching event into a hash table using the event key
and a value field named 'hitcount'.
To view the aggregation at any point in time, simply read the 'hist'
file in the same directory as the 'trigger' file:
# cat event/hist
The detailed syntax provides additional options for user control, and
is described exhaustively in Documentation/trace/events.txt and in the
virtual tracing/README file in the tracing subsystem.
Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
during bpf program loading remember the last byte of ctx access
and at the time of attaching the program to tracepoint check that
the program doesn't access bytes beyond defined in tracepoint fields
This also disallows access to __dynamic_array fields, but can be
relaxed in the future.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
split allows to move expensive update of 'struct trace_entry' to later phase.
Repurpose unused 1st argument of perf_tp_event() to indicate event type.
While splitting use temp variable 'rctx' instead of '*rctx' to avoid
unnecessary loads done by the compiler due to -fno-strict-aliasing
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull tracing updates from Steven Rostedt:
"Nothing major this round. Mostly small clean ups and fixes.
Some visible changes:
- A new flag was added to distinguish traces done in NMI context.
- Preempt tracer now shows functions where preemption is disabled but
interrupts are still enabled.
Other notes:
- Updates were done to function tracing to allow better performance
with perf.
- Infrastructure code has been added to allow for a new histogram
feature for recording live trace event histograms that can be
configured by simple user commands. The feature itself was just
finished, but needs a round in linux-next before being pulled.
This only includes some infrastructure changes that will be needed"
* tag 'trace-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (22 commits)
tracing: Record and show NMI state
tracing: Fix trace_printk() to print when not using bprintk()
tracing: Remove redundant reset per-CPU buff in irqsoff tracer
x86: ftrace: Fix the misleading comment for arch/x86/kernel/ftrace.c
tracing: Fix crash from reading trace_pipe with sendfile
tracing: Have preempt(irqs)off trace preempt disabled functions
tracing: Fix return while holding a lock in register_tracer()
ftrace: Use kasprintf() in ftrace_profile_tracefs()
ftrace: Update dynamic ftrace calls only if necessary
ftrace: Make ftrace_hash_rec_enable return update bool
tracing: Fix typoes in code comment and printk in trace_nop.c
tracing, writeback: Replace cgroup path to cgroup ino
tracing: Use flags instead of bool in trigger structure
tracing: Add an unreg_all() callback to trigger commands
tracing: Add needs_rec flag to event triggers
tracing: Add a per-event-trigger 'paused' field
tracing: Add get_syscall_name()
tracing: Add event record param to trigger_ops.func()
tracing: Make event trigger functions available
tracing: Make ftrace_event_field checking functions available
...
