linux/kernel/trace
Steven Rostedt (VMware) aba4b5c22c ftrace: Save module init functions kallsyms symbols for tracing
If function tracing is active when the module init functions are freed, then
store them to be referenced by kallsyms. As module init functions can now be
traced on module load, they were useless:

 ># echo ':mod:snd_seq' > set_ftrace_filter
 ># echo function > current_tracer
 ># modprobe snd_seq
 ># cat trace
 # tracer: function
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
         modprobe-2786  [000] ....  3189.037874: 0xffffffffa0860000 <-do_one_initcall
         modprobe-2786  [000] ....  3189.037876: 0xffffffffa086004d <-0xffffffffa086000f
         modprobe-2786  [000] ....  3189.037876: 0xffffffffa086010d <-0xffffffffa0860018
         modprobe-2786  [000] ....  3189.037877: 0xffffffffa086011a <-0xffffffffa0860021
         modprobe-2786  [000] ....  3189.037877: 0xffffffffa0860080 <-0xffffffffa086002a
         modprobe-2786  [000] ....  3189.039523: 0xffffffffa0860400 <-0xffffffffa0860033
         modprobe-2786  [000] ....  3189.039523: 0xffffffffa086038a <-0xffffffffa086041c
         modprobe-2786  [000] ....  3189.039591: 0xffffffffa086038a <-0xffffffffa0860436
         modprobe-2786  [000] ....  3189.039657: 0xffffffffa086038a <-0xffffffffa0860450
         modprobe-2786  [000] ....  3189.039719: 0xffffffffa0860127 <-0xffffffffa086003c
         modprobe-2786  [000] ....  3189.039742: snd_seq_create_kernel_client <-0xffffffffa08601f6

When the output is shown, the kallsyms for the module init functions have
already been freed, and the output of the trace can not convert them to
their function names.

Now this looks like this:

 # tracer: function
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
         modprobe-2463  [002] ....   174.243237: alsa_seq_init <-do_one_initcall
         modprobe-2463  [002] ....   174.243239: client_init_data <-alsa_seq_init
         modprobe-2463  [002] ....   174.243240: snd_sequencer_memory_init <-alsa_seq_init
         modprobe-2463  [002] ....   174.243240: snd_seq_queues_init <-alsa_seq_init
         modprobe-2463  [002] ....   174.243240: snd_sequencer_device_init <-alsa_seq_init
         modprobe-2463  [002] ....   174.244860: snd_seq_info_init <-alsa_seq_init
         modprobe-2463  [002] ....   174.244861: create_info_entry <-snd_seq_info_init
         modprobe-2463  [002] ....   174.244936: create_info_entry <-snd_seq_info_init
         modprobe-2463  [002] ....   174.245003: create_info_entry <-snd_seq_info_init
         modprobe-2463  [002] ....   174.245072: snd_seq_system_client_init <-alsa_seq_init
         modprobe-2463  [002] ....   174.245094: snd_seq_create_kernel_client <-snd_seq_system_client_init

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-10-05 17:57:33 -04:00
..
blktrace.c blktrace: Fix potential deadlock between delete & sysfs ops 2017-09-25 08:56:05 -06:00
bpf_trace.c bpf: fix bpf_trace_printk on 32 bit archs 2017-08-15 17:32:15 -07:00
ftrace.c ftrace: Save module init functions kallsyms symbols for tracing 2017-10-05 17:57:33 -04:00
Kconfig tracing: Rename update the enum_map file 2017-06-13 17:13:06 -04:00
Makefile perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS 2017-03-01 10:26:39 +01:00
power-traces.c cpufreq: schedutil: New governor based on scheduler utilization data 2016-04-02 01:09:12 +02:00
ring_buffer_benchmark.c ring-buffer: Have ring_buffer_alloc_read_page() return error on offline CPU 2017-08-02 14:23:02 -04:00
ring_buffer.c ring-buffer: Rewrite trace_recursive_(un)lock() to be simpler 2017-10-04 11:36:58 -04:00
rpm-traces.c
trace_benchmark.c tracing: Have the trace_event benchmark thread call cond_resched_rcu_qs() 2017-04-17 15:21:19 -04:00
trace_benchmark.h tracing: Have the reg function allow to fail 2016-12-09 09:13:30 -05:00
trace_branch.c tracing: Add the constant count for branch tracer 2017-01-19 08:57:41 -05:00
trace_clock.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h> 2017-03-02 08:42:27 +01:00
trace_entries.h trace: make trace_hwlat timestamp y2038 safe 2017-05-08 17:15:15 -07:00
trace_event_perf.c perf/ftrace: Fix double traces of perf on ftrace:function 2017-08-29 13:29:29 +02:00
trace_events_filter_test.h
trace_events_filter.c mm: treewide: remove GFP_TEMPORARY allocation flag 2017-09-13 18:53:16 -07:00
trace_events_hist.c tracing: Reimplement log2 2017-10-04 13:10:39 -04:00
trace_events_trigger.c sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h> 2017-03-02 08:42:38 +01:00
trace_events.c tracing: Reverse the order of trace_types_lock and event_mutex 2017-10-04 11:36:56 -04:00
trace_export.c tracing: ftrace_event_is_function() can return boolean 2015-11-02 14:28:05 -05:00
trace_functions_graph.c treewide: make "nr_cpu_ids" unsigned 2017-09-08 18:26:48 -07:00
trace_functions.c ftrace: Fix regression with module command in stack_trace_filter 2017-06-29 10:05:45 -04:00
trace_hwlat.c trace: make trace_hwlat timestamp y2038 safe 2017-05-08 17:15:15 -07:00
trace_irqsoff.c clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
trace_kdb.c tracing: Move trace_flags from global to a trace_array field 2015-09-30 15:22:55 -04:00
trace_kprobe.c tracing: Make traceprobe parsing code reusable 2017-10-04 13:06:44 -04:00
trace_mmiotrace.c tracing: Ignore mmiotrace from kernel commandline 2017-09-19 12:36:01 -04:00
trace_nop.c tracing: Fix typoes in code comment and printk in trace_nop.c 2016-03-08 11:23:57 -05:00
trace_output.c sched/tracing: Use common task-state helpers 2017-09-29 11:02:45 +02:00
trace_output.h tracing: Turn seq_print_user_ip() into a static function 2015-09-28 10:16:12 -04:00
trace_printk.c tracing: Handle NULL formats in hold_module_trace_bprintk_format() 2016-06-20 09:46:12 -04:00
trace_probe.c tracing: Make traceprobe parsing code reusable 2017-10-04 13:06:44 -04:00
trace_probe.h tracing: Make traceprobe parsing code reusable 2017-10-04 13:06:44 -04:00
trace_sched_switch.c tracing: Add support for recording tgid of tasks 2017-06-27 13:30:28 -04:00
trace_sched_wakeup.c sched/tracing: Use common task-state helpers 2017-09-29 11:02:45 +02:00
trace_selftest_dynamic.c
trace_selftest.c tracing: Remove obsolete sched_switch tracer selftest 2017-10-04 11:36:54 -04:00
trace_seq.c tracing: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:37 -08:00
trace_stack.c tracing: Remove RCU work arounds from stack tracer 2017-09-23 16:50:20 -04:00
trace_stat.c kernel/...: convert pr_warning to pr_warn 2016-03-22 15:36:02 -07:00
trace_stat.h
trace_syscalls.c perf/bpf: fix a clang compilation issue 2017-09-11 14:28:45 -07:00
trace_uprobe.c tracing: Make traceprobe parsing code reusable 2017-10-04 13:06:44 -04:00
trace.c tracing: Make traceprobe parsing code reusable 2017-10-04 13:06:44 -04:00
trace.h tracing: Make traceprobe parsing code reusable 2017-10-04 13:06:44 -04:00
tracing_map.c tracing: Remove lookups from tracing_map hitcount 2017-10-04 13:05:42 -04:00
tracing_map.h tracing: Increase tracing map KEYS_MAX size 2017-10-04 13:06:25 -04:00