Merge tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "New:

   - The Real Time Linux Analysis (RTLA) tool is added to the tools
     directory.

   - Can safely filter on user space pointers with: field.ustring ~
     "match-string"

   - eprobes can now be filtered like any other event.

   - trace_marker(_raw) now uses stream_open() to allow multiple threads
     to safely write to it. Note, this could possibly break existing
     user space, but we will not know until we hear about it, and then
     can revert the change if need be.

   - New field in events to display when bottom halfs are disabled.

   - Sorting of the ftrace functions are now done at compile time
     instead of at bootup.

  Infrastructure changes to support future efforts:

   - Added __rel_loc type for trace events. Similar to __data_loc but
     the offset to the dynamic data is based off of the location of the
     descriptor and not the beginning of the event. Needed for user
     defined events.

   - Some simplification of event trigger code.

   - Make synthetic events process its callback better to not hinder
     other event callbacks that are registered. Needed for user defined
     events.

  And other small fixes and cleanups"

* tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits)
  tracing: Add ustring operation to filtering string pointers
  rtla: Add rtla timerlat hist documentation
  rtla: Add rtla timerlat top documentation
  rtla: Add rtla timerlat documentation
  rtla: Add rtla osnoise hist documentation
  rtla: Add rtla osnoise top documentation
  rtla: Add rtla osnoise man page
  rtla: Add Documentation
  rtla/timerlat: Add timerlat hist mode
  rtla: Add timerlat tool and timelart top mode
  rtla/osnoise: Add the hist mode
  rtla/osnoise: Add osnoise top mode
  rtla: Add osnoise tool
  rtla: Helper functions for rtla
  rtla: Real-Time Linux Analysis tool
  tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails
  tracing: Remove duplicate warnings when calling trace_create_file()
  tracing/kprobes: 'nmissed' not showed correctly for kretprobe
  tracing: Add test for user space strings when filtering on string pointers
  tracing: Have syscall trace events use trace_event_buffer_lock_reserve()
  ...

17 files changed, 719 insertions, 0 deletions

diff --git a/Documentation/tools/rtla/Makefile b/Documentation/tools/rtla/Makefile
new file mode 100644
index 000000000000..9f2b84af1a6c
--- /dev/null
+++ b/Documentation/tools/rtla/Makefile
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# Based on bpftool's Documentation Makefile
+
+INSTALL		?= install
+RM		?= rm -f
+RMDIR		?= rmdir --ignore-fail-on-non-empty
+
+PREFIX		?= /usr/share
+MANDIR		?= $(PREFIX)/man
+MAN1DIR		= $(MANDIR)/man1
+
+MAN1_RST	= $(wildcard rtla*.rst)
+
+_DOC_MAN1	= $(patsubst %.rst,%.1,$(MAN1_RST))
+DOC_MAN1	= $(addprefix $(OUTPUT),$(_DOC_MAN1))
+
+RST2MAN_DEP	:= $(shell command -v rst2man 2>/dev/null)
+RST2MAN_OPTS	+= --verbose
+
+$(OUTPUT)%.1: %.rst
+ifndef RST2MAN_DEP
+	$(error "rst2man not found, but required to generate man pages")
+endif
+	rst2man $(RST2MAN_OPTS) $< > $@
+
+man1: $(DOC_MAN1)
+man: man1
+
+clean:
+	$(RM) $(DOC_MAN1)
+
+install: man
+	$(INSTALL) -d -m 755 $(DESTDIR)$(MAN1DIR)
+	$(INSTALL) -m 644 $(DOC_MAN1) $(DESTDIR)$(MAN1DIR)
+
+uninstall:
+	$(RM) $(addprefix $(DESTDIR)$(MAN1DIR)/,$(_DOC_MAN1))
+	$(RMDIR) $(DESTDIR)$(MAN1DIR)
+
+.PHONY: man man1 clean install uninstall
+.DEFAULT_GOAL := man
diff --git a/Documentation/tools/rtla/common_appendix.rst b/Documentation/tools/rtla/common_appendix.rst
new file mode 100644
index 000000000000..b494084acccd
--- /dev/null
+++ b/Documentation/tools/rtla/common_appendix.rst
@@ -0,0 +1,12 @@
+REPORTING BUGS
+==============
+Report bugs to <lkml@vger.kernel.org>
+
+LICENSE
+=======
+**rtla** is Free Software licensed under the GNU GPLv2
+
+COPYING
+=======
+Copyright \(C) 2021 Red Hat, Inc. Free use of this software is granted under
+the terms of the GNU Public License (GPL).
diff --git a/Documentation/tools/rtla/common_hist_options.rst b/Documentation/tools/rtla/common_hist_options.rst
new file mode 100644
index 000000000000..0266cd08a6c9
--- /dev/null
+++ b/Documentation/tools/rtla/common_hist_options.rst
@@ -0,0 +1,23 @@
+**-b**, **--bucket-size** *N*
+
+        Set the histogram bucket size (default *1*).
+
+**-e**, **--entries** *N*
+
+        Set the number of entries of the histogram (default 256).
+
+**--no-header**
+
+        Do not print header.
+
+**--no-summary**
+
+        Do not print summary.
+
+**--no-index**
+
+        Do not print index.
+
+**--with-zeros**
+
+        Print zero only entries.
diff --git a/Documentation/tools/rtla/common_options.rst b/Documentation/tools/rtla/common_options.rst
new file mode 100644
index 000000000000..721790ad984e
--- /dev/null
+++ b/Documentation/tools/rtla/common_options.rst
@@ -0,0 +1,28 @@
+**-c**, **--cpus** *cpu-list*
+
+        Set the osnoise tracer to run the sample threads in the cpu-list.
+
+**-d**, **--duration** *time[s|m|h|d]*
+
+        Set the duration of the session.
+
+**-D**, **--debug**
+
+        Print debug info.
+
+**-t**, **--trace**\[*=file*]
+
+        Save the stopped trace to [*file|osnoise_trace.txt*].
+
+**-P**, **--priority** *o:prio|r:prio|f:prio|d:runtime:period*
+
+        Set scheduling parameters to the osnoise tracer threads, the format to set the priority are:
+
+        - *o:prio* - use SCHED_OTHER with *prio*;
+        - *r:prio* - use SCHED_RR with *prio*;
+        - *f:prio* - use SCHED_FIFO with *prio*;
+        - *d:runtime[us|ms|s]:period[us|ms|s]* - use SCHED_DEADLINE with *runtime* and *period* in nanoseconds.
+
+**-h**, **--help**
+
+        Print help menu.
diff --git a/Documentation/tools/rtla/common_osnoise_description.rst b/Documentation/tools/rtla/common_osnoise_description.rst
new file mode 100644
index 000000000000..8973c5df888f
--- /dev/null
+++ b/Documentation/tools/rtla/common_osnoise_description.rst
@@ -0,0 +1,8 @@
+The **rtla osnoise** tool is an interface for the *osnoise* tracer. The
+*osnoise* tracer dispatches a kernel thread per-cpu. These threads read the
+time in a loop while with preemption, softirq and IRQs enabled, thus
+allowing all the sources of operating systme noise during its execution.
+The *osnoise*'s tracer threads take note of the delta between each time
+read, along with an interference counter of all sources of interference.
+At the end of each period, the *osnoise* tracer displays a summary of
+the results.
diff --git a/Documentation/tools/rtla/common_osnoise_options.rst b/Documentation/tools/rtla/common_osnoise_options.rst
new file mode 100644
index 000000000000..d556883e4e26
--- /dev/null
+++ b/Documentation/tools/rtla/common_osnoise_options.rst
@@ -0,0 +1,17 @@
+**-p**, **--period** *us*
+
+        Set the *osnoise* tracer period in microseconds.
+
+**-r**, **--runtime** *us*
+
+        Set the *osnoise* tracer runtime in microseconds.
+
+**-s**, **--stop** *us*
+
+        Stop the trace if a single sample is higher than the argument in microseconds.
+        If **-T** is set, it will also save the trace to the output.
+
+**-S**, **--stop-total** *us*
+
+        Stop the trace if the total sample is higher than the argument in microseconds.
+        If **-T** is set, it will also save the trace to the output.
diff --git a/Documentation/tools/rtla/common_timerlat_description.rst b/Documentation/tools/rtla/common_timerlat_description.rst
new file mode 100644
index 000000000000..321201cb8597
--- /dev/null
+++ b/Documentation/tools/rtla/common_timerlat_description.rst
@@ -0,0 +1,10 @@
+The **rtla timerlat** tool is an interface for the *timerlat* tracer. The
+*timerlat* tracer dispatches a kernel thread per-cpu. These threads
+set a periodic timer to wake themselves up and go back to sleep. After
+the wakeup, they collect and generate useful information for the
+debugging of operating system timer latency.
+
+The *timerlat* tracer outputs information in two ways. It periodically
+prints the timer latency at the timer *IRQ* handler and the *Thread*
+handler. It also enable the trace of the most relevant information via
+**osnoise:** tracepoints.
diff --git a/Documentation/tools/rtla/common_timerlat_options.rst b/Documentation/tools/rtla/common_timerlat_options.rst
new file mode 100644
index 000000000000..e9c1bfd55d48
--- /dev/null
+++ b/Documentation/tools/rtla/common_timerlat_options.rst
@@ -0,0 +1,16 @@
+**-p**, **--period** *us*
+
+        Set the *timerlat* tracer period in microseconds.
+
+**-i**, **--irq** *us*
+
+        Stop trace if the *IRQ* latency is higher than the argument in us.
+
+**-T**, **--thread** *us*
+
+        Stop trace if the *Thread* latency is higher than the argument in us.
+
+**-s**, **--stack** *us*
+
+        Save the stack trace at the *IRQ* if a *Thread* latency is higher than the
+        argument in us.
diff --git a/Documentation/tools/rtla/common_top_options.rst b/Documentation/tools/rtla/common_top_options.rst
new file mode 100644
index 000000000000..f48878938f84
--- /dev/null
+++ b/Documentation/tools/rtla/common_top_options.rst
@@ -0,0 +1,3 @@
+**-q**, **--quiet**
+
+        Print only a summary at the end of the session.
diff --git a/Documentation/tools/rtla/rtla-osnoise-hist.rst b/Documentation/tools/rtla/rtla-osnoise-hist.rst
new file mode 100644
index 000000000000..52298ddd8701
--- /dev/null
+++ b/Documentation/tools/rtla/rtla-osnoise-hist.rst
@@ -0,0 +1,66 @@
+===================
+rtla-osnoise-hist
+===================
+------------------------------------------------------
+Display a histogram of the osnoise tracer samples
+------------------------------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla osnoise hist** [*OPTIONS*]
+
+DESCRIPTION
+===========
+.. include:: common_osnoise_description.rst
+
+The **rtla osnoise hist** tool collects all **osnoise:sample_threshold**
+occurrence in a histogram, displaying the results in a user-friendly way.
+The tool also allows many configurations of the *osnoise* tracer and the
+collection of the tracer output.
+
+OPTIONS
+=======
+.. include:: common_osnoise_options.rst
+
+.. include:: common_hist_options.rst
+
+.. include:: common_options.rst
+
+EXAMPLE
+=======
+In the example below, *osnoise* tracer threads are set to run with real-time
+priority *FIFO:1*, on CPUs *0-11*, for *900ms* at each period (*1s* by
+default). The reason for reducing the runtime is to avoid starving the
+**rtla** tool. The tool is also set to run for *one minute*. The output
+histogram is set to group outputs in buckets of *10us* and *25* entries::
+
+  [root@f34 ~/]# rtla osnoise hist -P F:1 -c 0-11 -r 900000 -d 1M -b 10 -e 25
+  # RTLA osnoise histogram
+  # Time unit is microseconds (us)
+  # Duration:   0 00:01:00
+  Index   CPU-000   CPU-001   CPU-002   CPU-003   CPU-004   CPU-005   CPU-006   CPU-007   CPU-008   CPU-009   CPU-010   CPU-011
+  0         42982     46287     51779     53740     52024     44817     49898     36500     50408     50128     49523     52377
+  10        12224      8356      2912       878      2667     10155      4573     18894      4214      4836      5708      2413
+  20            8         5        12         2        13        24        20        41        29        53        39        39
+  30            1         1         0         0        10         3         6        19        15        31        30        38
+  40            0         0         0         0         0         4         2         7         2         3         8        11
+  50            0         0         0         0         0         0         0         0         0         1         1         2
+  over:         0         0         0         0         0         0         0         0         0         0         0         0
+  count:    55215     54649     54703     54620     54714     55003     54499     55461     54668     55052     55309     54880
+  min:          0         0         0         0         0         0         0         0         0         0         0         0
+  avg:          0         0         0         0         0         0         0         0         0         0         0         0
+  max:         30        30        20        20        30        40        40        40        40        50        50        50
+
+SEE ALSO
+========
+**rtla-osnoise**\(1), **rtla-osnoise-top**\(1)
+
+*osnoise* tracer documentation: <https://www.kernel.org/doc/html/latest/trace/osnoise-tracer.html>
+
+AUTHOR
+======
+Written by Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.rst
diff --git a/Documentation/tools/rtla/rtla-osnoise-top.rst b/Documentation/tools/rtla/rtla-osnoise-top.rst
new file mode 100644
index 000000000000..5d75d1394516
--- /dev/null
+++ b/Documentation/tools/rtla/rtla-osnoise-top.rst
@@ -0,0 +1,61 @@
+===================
+rtla-osnoise-top
+===================
+-----------------------------------------------
+Display a summary of the operating system noise
+-----------------------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla osnoise top** [*OPTIONS*]
+
+DESCRIPTION
+===========
+.. include:: common_osnoise_description.rst
+
+**rtla osnoise top** collects the periodic summary from the *osnoise* tracer,
+including the counters of the occurrence of the interference source,
+displaying the results in a user-friendly format.
+
+The tool also allows many configurations of the *osnoise* tracer and the
+collection of the tracer output.
+
+OPTIONS
+=======
+.. include:: common_osnoise_options.rst
+
+.. include:: common_top_options.rst
+
+.. include:: common_options.rst
+
+EXAMPLE
+=======
+In the example below, the **rtla osnoise top** tool is set to run with a
+real-time priority *FIFO:1*, on CPUs *0-3*, for *900ms* at each period
+(*1s* by default). The reason for reducing the runtime is to avoid starving
+the rtla tool. The tool is also set to run for *one minute* and to display
+a summary of the report at the end of the session::
+
+  [root@f34 ~]# rtla osnoise top -P F:1 -c 0-3 -r 900000 -d 1M -q
+                                          Operating System Noise
+  duration:   0 00:01:00 | time is in us
+  CPU Period       Runtime        Noise  % CPU Aval   Max Noise   Max Single          HW          NMI          IRQ      Softirq       Thread
+    0 #59         53100000       304896    99.42580        6978           56         549            0        53111         1590           13
+    1 #59         53100000       338339    99.36282        8092           24         399            0        53130         1448           31
+    2 #59         53100000       290842    99.45227        6582           39         855            0        53110         1406           12
+    3 #59         53100000       204935    99.61405        6251           33         290            0        53156         1460           12
+
+SEE ALSO
+========
+
+**rtla-osnoise**\(1), **rtla-osnoise-hist**\(1)
+
+Osnoise tracer documentation: <https://www.kernel.org/doc/html/latest/trace/osnoise-tracer.html>
+
+AUTHOR
+======
+Written by Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.rst
diff --git a/Documentation/tools/rtla/rtla-osnoise.rst b/Documentation/tools/rtla/rtla-osnoise.rst
new file mode 100644
index 000000000000..c129b206ce34
--- /dev/null
+++ b/Documentation/tools/rtla/rtla-osnoise.rst
@@ -0,0 +1,59 @@
+===============
+rtla-osnoise
+===============
+------------------------------------------------------------------
+Measure the operating system noise
+------------------------------------------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla osnoise** [*MODE*] ...
+
+DESCRIPTION
+===========
+
+.. include:: common_osnoise_description.rst
+
+The *osnoise* tracer outputs information in two ways. It periodically prints
+a summary of the noise of the operating system, including the counters of
+the occurrence of the source of interference. It also provides information
+for each noise via the **osnoise:** tracepoints. The **rtla osnoise top**
+mode displays information about the periodic summary from the *osnoise* tracer.
+The **rtla osnoise hist** mode displays information about the noise using
+the **osnoise:** tracepoints. For further details, please refer to the
+respective man page.
+
+MODES
+=====
+**top**
+
+        Prints the summary from osnoise tracer.
+
+**hist**
+
+        Prints a histogram of osnoise samples.
+
+If no MODE is given, the top mode is called, passing the arguments.
+
+OPTIONS
+=======
+
+**-h**, **--help**
+
+        Display the help text.
+
+For other options, see the man page for the corresponding mode.
+
+SEE ALSO
+========
+**rtla-osnoise-top**\(1), **rtla-osnoise-hist**\(1)
+
+Osnoise tracer documentation: <https://www.kernel.org/doc/html/latest/trace/osnoise-tracer.html>
+
+AUTHOR
+======
+Written by Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.rst
diff --git a/Documentation/tools/rtla/rtla-timerlat-hist.rst b/Documentation/tools/rtla/rtla-timerlat-hist.rst
new file mode 100644
index 000000000000..e12eae1f3301
--- /dev/null
+++ b/Documentation/tools/rtla/rtla-timerlat-hist.rst
@@ -0,0 +1,106 @@
+=====================
+rtla-timerlat-hist
+=====================
+------------------------------------------------
+Histograms of the operating system timer latency
+------------------------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla timerlat hist** [*OPTIONS*] ...
+
+DESCRIPTION
+===========
+
+.. include:: common_timerlat_description.rst
+
+The **rtla timerlat hist** displays a histogram of each tracer event
+occurrence. This tool uses the periodic information, and the
+**osnoise:** tracepoints are enabled when using the **-T** option.
+
+OPTIONS
+=======
+
+.. include:: common_timerlat_options.rst
+
+.. include:: common_hist_options.rst
+
+.. include:: common_options.rst
+
+EXAMPLE
+=======
+In the example below, **rtla timerlat hist** is set to run for *10* minutes,
+in the cpus *0-4*, *skipping zero* only lines. Moreover, **rtla timerlat
+hist** will change the priority of the *timelat* threads to run under
+*SCHED_DEADLINE* priority, with a *10us* runtime every *1ms* period. The
+*1ms* period is also passed to the *timerlat* tracer::
+
+  [root@alien ~]# timerlat hist -d 10m -c 0-4 -P d:100us:1ms -p 1ms
+  # RTLA timerlat histogram
+  # Time unit is microseconds (us)
+  # Duration:   0 00:10:00
+  Index   IRQ-000   Thr-000   IRQ-001   Thr-001   IRQ-002   Thr-002   IRQ-003   Thr-003   IRQ-004   Thr-004
+  0        276489         0    206089         0    466018         0    481102         0    205546         0
+  1        318327     35487    388149     30024     94531     48382     83082     71078    388026     55730
+  2          3282    122584      4019    126527     28231    109012     23311     89309      4568     98739
+  3           940     11815       837      9863      6209     16227      6895     17196       910      9780
+  4           444     17287       424     11574      2097     38443      2169     36736       462     13476
+  5           206     43291       255     25581      1223    101908      1304    101137       236     28913
+  6           132    101501        96     64584       635    213774       757    215471        99     73453
+  7            74    169347        65    124758       350     57466       441     53639        69    148573
+  8            53     85183        31    156751       229      9052       306      9026        39    139907
+  9            22     10387        12     42762       161      2554       225      2689        19     26192
+  10           13      1898         8      5770       114      1247       128      1405        13      3772
+  11            9       560         9       924        71       686        76       765         8       713
+  12            4       256         2       360        50       411        64       474         3       278
+  13            2       167         2       172        43       256        53       350         4       180
+  14            1        88         1       116        15       198        42       223         0       115
+  15            2        63         3        94        11       139        20       150         0        58
+  16            2        37         0        56         5        78        10       102         0        39
+  17            0        18         0        28         4        57         8        80         0        15
+  18            0         8         0        17         2        50         6        56         0        12
+  19            0         9         0         5         0        19         0        48         0        18
+  20            0         4         0         8         0        11         2        27         0         4
+  21            0         2         0         3         1         9         1        18         0         6
+  22            0         1         0         3         1         7         0         3         0         5
+  23            0         2         0         4         0         2         0         7         0         2
+  24            0         2         0         2         1         3         0         3         0         5
+  25            0         0         0         1         0         1         0         1         0         3
+  26            0         1         0         0         0         2         0         2         0         0
+  27            0         0         0         3         0         1         0         0         0         1
+  28            0         0         0         3         0         0         0         1         0         0
+  29            0         0         0         2         0         2         0         1         0         3
+  30            0         1         0         0         0         0         0         0         0         0
+  31            0         1         0         0         0         0         0         2         0         2
+  32            0         0         0         1         0         2         0         0         0         0
+  33            0         0         0         2         0         0         0         0         0         1
+  34            0         0         0         0         0         0         0         0         0         2
+  35            0         1         0         1         0         0         0         0         0         1
+  36            0         1         0         0         0         1         0         1         0         0
+  37            0         0         0         1         0         0         0         0         0         0
+  40            0         0         0         0         0         1         0         1         0         0
+  41            0         0         0         0         0         0         0         0         0         1
+  42            0         0         0         0         0         0         0         0         0         1
+  44            0         0         0         0         0         1         0         0         0         0
+  46            0         0         0         0         0         0         0         1         0         0
+  47            0         0         0         0         0         0         0         0         0         1
+  50            0         0         0         0         0         0         0         0         0         1
+  54            0         0         0         1         0         0         0         0         0         0
+  58            0         0         0         1         0         0         0         0         0         0
+  over:         0         0         0         0         0         0         0         0         0         0
+  count:   600002    600002    600002    600002    600002    600002    600002    600002    600002    600002
+  min:          0         1         0         1         0         1         0         1         0         1
+  avg:          0         5         0         5         0         4         0         4         0         5
+  max:         16        36        15        58        24        44        21        46        13        50
+
+SEE ALSO
+========
+**rtla-timerlat**\(1), **rtla-timerlat-top**\(1)
+
+*timerlat* tracer documentation: <https://www.kernel.org/doc/html/latest/trace/timerlat-tracer.html>
+
+AUTHOR
+======
+Written by Daniel Bristot de Oliveira <bristot@kernel.org>
diff --git a/Documentation/tools/rtla/rtla-timerlat-top.rst b/Documentation/tools/rtla/rtla-timerlat-top.rst
new file mode 100644
index 000000000000..1c321de1c171
--- /dev/null
+++ b/Documentation/tools/rtla/rtla-timerlat-top.rst
@@ -0,0 +1,145 @@
+====================
+rtla-timerlat-top
+====================
+-------------------------------------------
+Measures the operating system timer latency
+-------------------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla timerlat top** [*OPTIONS*] ...
+
+DESCRIPTION
+===========
+
+.. include:: common_timerlat_description.rst
+
+The **rtla timerlat top** displays a summary of the periodic output
+from the *timerlat* tracer. It also provides information for each
+operating system noise via the **osnoise:** tracepoints that can be
+seem with the option **-T**.
+
+OPTIONS
+=======
+
+.. include:: common_timerlat_options.rst
+
+.. include:: common_top_options.rst
+
+.. include:: common_options.rst
+
+EXAMPLE
+=======
+
+In the example below, the *timerlat* tracer is set to capture the stack trace at
+the IRQ handler, printing it to the buffer if the *Thread* timer latency is
+higher than *30 us*. It is also set to stop the session if a *Thread* timer
+latency higher than *30 us* is hit. Finally, it is set to save the trace
+buffer if the stop condition is hit::
+
+  [root@alien ~]# rtla timerlat top -s 30 -t 30 -T
+                   Timer Latency
+    0 00:00:59   |          IRQ Timer Latency (us)        |         Thread Timer Latency (us)
+  CPU COUNT      |      cur       min       avg       max |      cur       min       avg       max
+    0 #58634     |        1         0         1        10 |       11         2        10        23
+    1 #58634     |        1         0         1         9 |       12         2         9        23
+    2 #58634     |        0         0         1        11 |       10         2         9        23
+    3 #58634     |        1         0         1        11 |       11         2         9        24
+    4 #58634     |        1         0         1        10 |       11         2         9        26
+    5 #58634     |        1         0         1         8 |       10         2         9        25
+    6 #58634     |       12         0         1        12 |       30         2        10        30 <--- CPU with spike
+    7 #58634     |        1         0         1         9 |       11         2         9        23
+    8 #58633     |        1         0         1         9 |       11         2         9        26
+    9 #58633     |        1         0         1         9 |       10         2         9        26
+   10 #58633     |        1         0         1        13 |       11         2         9        28
+   11 #58633     |        1         0         1        13 |       12         2         9        24
+   12 #58633     |        1         0         1         8 |       10         2         9        23
+   13 #58633     |        1         0         1        10 |       10         2         9        22
+   14 #58633     |        1         0         1        18 |       12         2         9        27
+   15 #58633     |        1         0         1        10 |       11         2         9        28
+   16 #58633     |        0         0         1        11 |        7         2         9        26
+   17 #58633     |        1         0         1        13 |       10         2         9        24
+   18 #58633     |        1         0         1         9 |       13         2         9        22
+   19 #58633     |        1         0         1        10 |       11         2         9        23
+   20 #58633     |        1         0         1        12 |       11         2         9        28
+   21 #58633     |        1         0         1        14 |       11         2         9        24
+   22 #58633     |        1         0         1         8 |       11         2         9        22
+   23 #58633     |        1         0         1        10 |       11         2         9        27
+  timerlat hit stop tracing
+  saving trace to timerlat_trace.txt
+  [root@alien bristot]# tail -60 timerlat_trace.txt
+  [...]
+      timerlat/5-79755   [005] .......   426.271226: #58634 context thread timer_latency     10823 ns
+              sh-109404  [006] dnLh213   426.271247: #58634 context    irq timer_latency     12505 ns
+              sh-109404  [006] dNLh313   426.271258: irq_noise: local_timer:236 start 426.271245463 duration 12553 ns
+              sh-109404  [006] d...313   426.271263: thread_noise:       sh:109404 start 426.271245853 duration 4769 ns
+      timerlat/6-79756   [006] .......   426.271264: #58634 context thread timer_latency     30328 ns
+      timerlat/6-79756   [006] ....1..   426.271265: <stack trace>
+  => timerlat_irq
+  => __hrtimer_run_queues
+  => hrtimer_interrupt
+  => __sysvec_apic_timer_interrupt
+  => sysvec_apic_timer_interrupt
+  => asm_sysvec_apic_timer_interrupt
+  => _raw_spin_unlock_irqrestore			<---- spinlock that disabled interrupt.
+  => try_to_wake_up
+  => autoremove_wake_function
+  => __wake_up_common
+  => __wake_up_common_lock
+  => ep_poll_callback
+  => __wake_up_common
+  => __wake_up_common_lock
+  => fsnotify_add_event
+  => inotify_handle_inode_event
+  => fsnotify
+  => __fsnotify_parent
+  => __fput
+  => task_work_run
+  => exit_to_user_mode_prepare
+  => syscall_exit_to_user_mode
+  => do_syscall_64
+  => entry_SYSCALL_64_after_hwframe
+  => 0x7265000001378c
+  => 0x10000cea7
+  => 0x25a00000204a
+  => 0x12e302d00000000
+  => 0x19b51010901b6
+  => 0x283ce00726500
+  => 0x61ea308872
+  => 0x00000fe3
+            bash-109109  [007] d..h...   426.271265: #58634 context    irq timer_latency      1211 ns
+      timerlat/6-79756   [006] .......   426.271267: timerlat_main: stop tracing hit on cpu 6
+
+In the trace, it is possible the notice that the *IRQ* timer latency was
+already high, accounting *12505 ns*. The IRQ delay was caused by the
+*bash-109109* process that disabled IRQs in the wake-up path
+(*_try_to_wake_up()* function). The duration of the IRQ handler that woke
+up the timerlat thread, informed with the **osnoise:irq_noise** event, was
+also high and added more *12553 ns* to the Thread latency. Finally, the
+**osnoise:thread_noise** added by the currently running thread (including
+the scheduling overhead) added more *4769 ns*. Summing up these values,
+the *Thread* timer latency accounted for *30328 ns*.
+
+The primary reason for this high value is the wake-up path that was hit
+twice during this case: when the *bash-109109* was waking up a thread
+and then when the *timerlat* thread was awakened. This information can
+then be used as the starting point of a more fine-grained analysis.
+
+Note that **rtla timerlat** was dispatched without changing *timerlat* tracer
+threads' priority. That is generally not needed because these threads hava
+priority *FIFO:95* by default, which is a common priority used by real-time
+kernel developers to analyze scheduling delays.
+
+SEE ALSO
+--------
+**rtla-timerlat**\(1), **rtla-timerlat-hist**\(1)
+
+*timerlat* tracer documentation: <https://www.kernel.org/doc/html/latest/trace/timerlat-tracer.html>
+
+AUTHOR
+------
+Written by Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.rst
diff --git a/Documentation/tools/rtla/rtla-timerlat.rst b/Documentation/tools/rtla/rtla-timerlat.rst
new file mode 100644
index 000000000000..44a49e6f302b
--- /dev/null
+++ b/Documentation/tools/rtla/rtla-timerlat.rst
@@ -0,0 +1,57 @@
+================
+rtla-timerlat
+================
+-------------------------------------------
+Measures the operating system timer latency
+-------------------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla timerlat** [*MODE*] ...
+
+DESCRIPTION
+===========
+
+.. include:: common_timerlat_description.rst
+
+The *timerlat* tracer outputs information in two ways. It periodically
+prints the timer latency at the timer *IRQ* handler and the *Thread* handler.
+It also provides information for each noise via the **osnoise:** tracepoints.
+The **rtla timerlat top** mode displays a summary of the periodic output
+from the *timerlat* tracer. The **rtla hist hist** mode displays a histogram
+of each tracer event occurrence. For further details, please refer to the
+respective man page.
+
+MODES
+=====
+**top**
+
+        Prints the summary from *timerlat* tracer.
+
+**hist**
+
+        Prints a histogram of timerlat samples.
+
+If no *MODE* is given, the top mode is called, passing the arguments.
+
+OPTIONS
+=======
+**-h**, **--help**
+
+        Display the help text.
+
+For other options, see the man page for the corresponding mode.
+
+SEE ALSO
+========
+**rtla-timerlat-top**\(1), **rtla-timerlat-hist**\(1)
+
+*timerlat* tracer documentation: <https://www.kernel.org/doc/html/latest/trace/timerlat-tracer.html>
+
+AUTHOR
+======
+Written by Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.rst
diff --git a/Documentation/tools/rtla/rtla.rst b/Documentation/tools/rtla/rtla.rst
new file mode 100644
index 000000000000..fc0d233efcd5
--- /dev/null
+++ b/Documentation/tools/rtla/rtla.rst
@@ -0,0 +1,48 @@
+=========
+rtla
+=========
+--------------------------------
+Real-time Linux Analysis tool
+--------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla** *COMMAND* [*OPTIONS*]
+
+DESCRIPTION
+===========
+The **rtla** is a meta-tool that includes a set of commands that aims to
+analyze the real-time properties of Linux. But instead of testing Linux
+as a black box, **rtla** leverages kernel tracing capabilities to provide
+precise information about the properties and root causes of unexpected
+results.
+
+COMMANDS
+========
+**osnoise**
+
+        Gives information about the operating system noise (osnoise).
+
+**timerlat**
+
+        Measures the IRQ and thread timer latency.
+
+OPTIONS
+=======
+**-h**, **--help**
+
+        Display the help text.
+
+For other options, see the man page for the corresponding command.
+
+SEE ALSO
+========
+**rtla-osnoise**\(1), **rtla-timerlat**\(1)
+
+AUTHOR
+======
+Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.rst
diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
index 8ddb9b09451c..c47f381d0c00 100644
--- a/Documentation/trace/events.rst
+++ b/Documentation/trace/events.rst
@@ -198,6 +198,15 @@ The glob (~) accepts a wild card character (\*,?) and character classes
   prev_comm ~ "*sh*"
   prev_comm ~ "ba*sh"
 
+If the field is a pointer that points into user space (for example
+"filename" from sys_enter_openat), then you have to append ".ustring" to the
+field name::
+
+  filename.ustring ~ "password"
+
+As the kernel will have to know how to retrieve the memory that the pointer
+is at from user space.
+
 5.2 Setting filters
 -------------------
 
@@ -230,6 +239,16 @@ Currently the caret ('^') for an error always appears at the beginning of
 the filter string; the error message should still be useful though
 even without more accurate position info.
 
+5.2.1 Filter limitations
+------------------------
+
+If a filter is placed on a string pointer ``(char *)`` that does not point
+to a string on the ring buffer, but instead points to kernel or user space
+memory, then, for safety reasons, at most 1024 bytes of the content is
+copied onto a temporary buffer to do the compare. If the copy of the memory
+faults (the pointer points to memory that should not be accessed), then the
+string compare will be treated as not matching.
+
 5.3 Clearing filters
 --------------------