linux/kernel/trace
Linus Torvalds 614cb2751d tracing: Limit the shooting in the foot of tp_printk
The "tp_printk" option redirects the trace event output to printk at boot
 up. This is useful when a machine crashes before boot where the trace events
 can not be retrieved by the in kernel ring buffer. But it can be "dangerous"
 because trace events can be located in high frequency locations such as
 interrupts and the scheduler, where a printk can slow it down that it live
 locks the machine (because by the time the printk finishes, the next event
 is triggered). Thus tp_printk must be used with care.
 
 It was discovered that the filter logic to trace events does not apply to
 the tp_printk events. This can cause a surprise and live lock when the user
 expects it to be filtered to limit the amount of events printed to the
 console when in fact it still prints everything.
 -----BEGIN PGP SIGNATURE-----
 
 iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYRwL+RQccm9zdGVkdEBn
 b29kbWlzLm9yZwAKCRAp5XQQmuv6qkRHAP9gvTYH1es9l4V5SNFEQ7+GEwknsaq7
 B5q4znVKQKgajQD/cd5Cm/alTIbxXdrQ9nxJ7lfffrvk46iqAb9PRX9vhAQ=
 =8QxT
 -----END PGP SIGNATURE-----

Merge tag 'trace-v5.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fix from Steven Rostedt:
 "Limit the shooting in the foot of tp_printk

  The "tp_printk" option redirects the trace event output to printk at
  boot up. This is useful when a machine crashes before boot where the
  trace events can not be retrieved by the in kernel ring buffer. But it
  can be "dangerous" because trace events can be located in high
  frequency locations such as interrupts and the scheduler, where a
  printk can slow it down that it live locks the machine (because by the
  time the printk finishes, the next event is triggered). Thus tp_printk
  must be used with care.

  It was discovered that the filter logic to trace events does not apply
  to the tp_printk events. This can cause a surprise and live lock when
  the user expects it to be filtered to limit the amount of events
  printed to the console when in fact it still prints everything"

* tag 'trace-v5.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Apply trace filters on all output channels
2021-08-17 09:47:18 -10:00
..
blktrace.c block-5.12-2021-02-27 2021-02-28 11:23:38 -08:00
bpf_trace.c bpf: Add lockdown check for probe_write_user helper 2021-08-10 10:10:10 +02:00
bpf_trace.h
error_report-traces.c tracing: add error_report_end trace point 2021-02-26 09:41:02 -08:00
fgraph.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
ftrace_internal.h
ftrace.c ftrace: Remove redundant initialization of variable ret 2021-07-23 08:46:02 -04:00
Kconfig tracing: define needed config DYNAMIC_FTRACE_WITH_ARGS 2021-08-12 13:35:57 -04:00
kprobe_event_gen_test.c
Makefile trace: Add osnoise tracer 2021-06-25 19:57:01 -04:00
power-traces.c
preemptirq_delay_test.c kernel: trace: preemptirq_delay_test: add cpu affinity 2021-02-02 17:02:07 -05:00
ring_buffer_benchmark.c
ring_buffer.c tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop. 2021-07-22 11:52:33 -04:00
rpm-traces.c
synth_event_gen_test.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_benchmark.c
trace_benchmark.h
trace_boot.c tracing/boot: Add per-group/all events enablement 2021-06-10 11:16:20 -04:00
trace_branch.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-18 09:10:00 -04:00
trace_dynevent.c tracing/dynevent: Fix a memory leak in an error handling path 2021-04-13 12:29:48 -04:00
trace_dynevent.h tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace_entries.h trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
trace_event_perf.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_events_filter_test.h
trace_events_filter.c tracing: Update create_system_filter() kernel-doc comment 2021-03-25 16:04:35 -04:00
trace_events_hist.c tracing / histogram: Fix NULL pointer dereference on strcmp() on NULL event name 2021-08-12 13:35:57 -04:00
trace_events_inject.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_events_synth.c tracing: Clean up alloc_synth_event() 2021-07-23 08:45:30 -04:00
trace_events_trigger.c tracing: Fix set_named_trigger_data() kernel-doc comment 2021-06-10 11:16:20 -04:00
trace_events.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_export.c
trace_functions_graph.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_functions.c tracing: Add "func_no_repeats" option for function tracing 2021-04-15 14:50:02 -04:00
trace_hwlat.c tracing: Quiet smp_processor_id() use in preemptable warning in hwlat 2021-08-05 09:27:31 -04:00
trace_irqsoff.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_kdb.c
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_mmiotrace.c tracing: Remove definition of DEBUG in trace_mmiotrace.c 2021-02-02 17:02:07 -05:00
trace_nop.c
trace_osnoise.c trace/osnoise: Print a stop tracing message 2021-08-12 13:35:56 -04:00
trace_output.c trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
trace_output.h
trace_preemptirq.c
trace_printk.c tracing: Add a verifier to check string pointers for trace events 2021-03-18 12:58:27 -04:00
trace_probe_tmpl.h tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_probe.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_probe.h tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_recursion_record.c
trace_sched_switch.c
trace_sched_wakeup.c tracing: Change variable type as bool for clean-up 2021-06-30 09:19:14 -04:00
trace_selftest_dynamic.c
trace_selftest.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_seq.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_stack.c
trace_stat.c
trace_stat.h
trace_synth.h tracing: Synthetic event field_pos is an index not a boolean 2021-07-23 08:43:04 -04:00
trace_syscalls.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_uprobe.c tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace.c tracing: Apply trace filters on all output channels 2021-08-16 11:01:52 -04:00
trace.h tracing: Apply trace filters on all output channels 2021-08-16 11:01:52 -04:00
tracing_map.c
tracing_map.h