Merge tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "New tracing features:

   - The ring buffer is no longer disabled when reading the trace file.

     The trace_pipe file was made to be used for live tracing and
     reading as it acted like the normal producer/consumer. As the trace
     file would not consume the data, the easy way of handling it was to
     just disable writes to the ring buffer.

     This came to a surprise to the BPF folks who complained about lost
     events due to reading. This is no longer an issue. If someone wants
     to keep the old disabling there's a new option "pause-on-trace"
     that can be set.

   - New set_ftrace_notrace_pid file. PIDs in this file will not be
     traced by the function tracer.

     Similar to set_ftrace_pid, which makes the function tracer only
     trace those tasks with PIDs in the file, the set_ftrace_notrace_pid
     does the reverse.

   - New set_event_notrace_pid file. PIDs in this file will cause events
     not to be traced if triggered by a task with a matching PID.

     Similar to the set_event_pid file but will not be traced. Note,
     sched_waking and sched_switch events may still be traced if one of
     the tasks referenced by those events contains a PID that is allowed
     to be traced.

  Tracing related features:

   - New bootconfig option, that is attached to the initrd file.

     If bootconfig is on the command line, then the initrd file is
     searched looking for a bootconfig appended at the end.

   - New GPU tracepoint infrastructure to help the gfx drivers to get
     off debugfs (acked by Greg Kroah-Hartman)

  And other minor updates and fixes"

* tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits)
  tracing: Do not allocate buffer in trace_find_next_entry() in atomic
  tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid
  selftests/ftrace: Add test to test new set_event_notrace_pid file
  selftests/ftrace: Add test to test new set_ftrace_notrace_pid file
  tracing: Create set_event_notrace_pid to not trace tasks
  ftrace: Create set_ftrace_notrace_pid to not trace tasks
  ftrace: Make function trace pid filtering a bit more exact
  ftrace/kprobe: Show the maxactive number on kprobe_events
  tracing: Have the document reflect that the trace file keeps tracing enabled
  ring-buffer/tracing: Have iterator acknowledge dropped events
  tracing: Do not disable tracing when reading the trace file
  ring-buffer: Do not disable recording when there is an iterator
  ring-buffer: Make resize disable per cpu buffer instead of total buffer
  ring-buffer: Optimize rb_iter_head_event()
  ring-buffer: Do not die if rb_iter_peek() fails more than thrice
  ring-buffer: Have rb_iter_head_event() handle concurrent writer
  ring-buffer: Add page_stamp to iterator for synchronization
  ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()
  ring-buffer: Have ring_buffer_empty() not depend on tracing stopped
  tracing: Save off entry when peeking at next entry
  ...

tools/testing/selftests/ftrace/test.d/event/event-no-pid.tc

@@ -0,0 +1,125 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event tracing - restricts events based on pid notrace filtering
+# flags: instance
+
+do_reset() {
+    echo > set_event
+    echo > set_event_pid
+    echo > set_event_notrace_pid
+    echo 0 > options/event-fork
+    echo 0 > events/enable
+    clear_trace
+    echo 1 > tracing_on
+}
+
+fail() { #msg
+    cat trace
+    do_reset
+    echo $1
+    exit_fail
+}
+
+count_pid() {
+    pid=$@
+    cat trace | grep -v '^#' | sed -e 's/[^-]*-\([0-9]*\).*/\1/' | grep $pid | wc -l
+}
+
+count_no_pid() {
+    pid=$1
+    cat trace | grep -v '^#' | sed -e 's/[^-]*-\([0-9]*\).*/\1/' | grep -v $pid | wc -l
+}
+
+enable_system() {
+    system=$1
+
+    if [ -d events/$system ]; then
+	echo 1 > events/$system/enable
+    fi
+}
+
+enable_events() {
+    echo 0 > tracing_on
+    # Enable common groups of events, as all events can allow for
+    # events to be traced via scheduling that we don't care to test.
+    enable_system syscalls
+    enable_system rcu
+    enable_system block
+    enable_system exceptions
+    enable_system irq
+    enable_system net
+    enable_system power
+    enable_system signal
+    enable_system sock
+    enable_system timer
+    enable_system thermal
+    echo 1 > tracing_on
+}
+
+if [ ! -f set_event -o ! -d events/sched ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f set_event_pid -o ! -f set_event_notrace_pid ]; then
+    echo "event pid notrace filtering is not supported"
+    exit_unsupported
+fi
+
+echo 0 > options/event-fork
+
+do_reset
+
+read mypid rest < /proc/self/stat
+
+echo $mypid > set_event_notrace_pid
+grep -q $mypid set_event_notrace_pid
+
+enable_events
+
+yield
+
+echo 0 > tracing_on
+
+cnt=`count_pid $mypid`
+if [ $cnt -ne 0 ]; then
+    fail "Filtered out task has events"
+fi
+
+cnt=`count_no_pid $mypid`
+if [ $cnt -eq 0 ]; then
+    fail "No other events were recorded"
+fi
+
+do_reset
+
+echo $mypid > set_event_notrace_pid
+echo 1 > options/event-fork
+
+enable_events
+
+yield &
+child=$!
+echo "child = $child"
+wait $child
+
+echo 0 > tracing_on
+
+cnt=`count_pid $mypid`
+if [ $cnt -ne 0 ]; then
+    fail "Filtered out task has events"
+fi
+
+cnt=`count_pid $child`
+if [ $cnt -ne 0 ]; then
+    fail "Child of filtered out taskhas events"
+fi
+
+cnt=`count_no_pid $mypid`
+if [ $cnt -eq 0 ]; then
+    fail "No other events were recorded"
+fi
+
+do_reset
+
+exit 0

tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc

@@ -0,0 +1,108 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: ftrace - function pid notrace filters
+# flags: instance
+
+# Make sure that function pid matching filter with notrace works.
+
+if ! grep -q function available_tracers; then
+    echo "no function tracer configured"
+    exit_unsupported
+fi
+
+if [ ! -f set_ftrace_notrace_pid ]; then
+    echo "set_ftrace_notrace_pid not found? Is function tracer not set?"
+    exit_unsupported
+fi
+
+if [ ! -f set_ftrace_filter ]; then
+    echo "set_ftrace_filter not found? Is function tracer not set?"
+    exit_unsupported
+fi
+
+do_function_fork=1
+
+if [ ! -f options/function-fork ]; then
+    do_function_fork=0
+    echo "no option for function-fork found. Option will not be tested."
+fi
+
+read PID _ < /proc/self/stat
+
+if [ $do_function_fork -eq 1 ]; then
+    # default value of function-fork option
+    orig_value=`grep function-fork trace_options`
+fi
+
+do_reset() {
+    if [ $do_function_fork -eq 0 ]; then
+	return
+    fi
+
+    echo > set_ftrace_notrace_pid
+    echo $orig_value > trace_options
+}
+
+fail() { # msg
+    do_reset
+    echo $1
+    exit_fail
+}
+
+do_test() {
+    disable_tracing
+
+    echo do_execve* > set_ftrace_filter
+    echo *do_fork >> set_ftrace_filter
+
+    echo $PID > set_ftrace_notrace_pid
+    echo function > current_tracer
+
+    if [ $do_function_fork -eq 1 ]; then
+	# don't allow children to be traced
+	echo nofunction-fork > trace_options
+    fi
+
+    enable_tracing
+    yield
+
+    count_pid=`cat trace | grep -v ^# | grep $PID | wc -l`
+    count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l`
+
+    # count_pid should be 0
+    if [ $count_pid -ne 0 -o $count_other -eq 0 ]; then
+	fail "PID filtering not working? traced task = $count_pid; other tasks = $count_other "
+    fi
+
+    disable_tracing
+    clear_trace
+
+    if [ $do_function_fork -eq 0 ]; then
+	return
+    fi
+
+    # allow children to be traced
+    echo function-fork > trace_options
+
+    # With pid in both set_ftrace_pid and set_ftrace_notrace_pid
+    # there should not be any tasks traced.
+
+    echo $PID > set_ftrace_pid
+
+    enable_tracing
+    yield
+
+    count_pid=`cat trace | grep -v ^# | grep $PID | wc -l`
+    count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l`
+
+    # both should be zero
+    if [ $count_pid -ne 0 -o $count_other -ne 0 ]; then
+	fail "PID filtering not following fork? traced task = $count_pid; other tasks = $count_other "
+    fi
+}
+
+do_test
+
+do_reset
+
+exit 0

tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc

@@ -41,7 +41,7 @@ fi
 
 echo '** ENABLE EVENTS'
 
-echo 1 > events/enable
+echo 1 > events/sched/enable
 
 echo '** ENABLE TRACING'
 enable_tracing