[PATCH 0/4] tools/bootconfig: Preserve tracing settings during export

[PATCH 0/4] tools/bootconfig: Preserve tracing settings during export

[Eduardo Mucelli Rezende Oliveira]

Hi Masami,

Here are four more fixes for ftrace2bconf.sh, based on bootconfig/fixes.
They address settings that change or fail to restore after export:

- Event filters containing punctuation are quoted as one bootconfig value.
- Generic trigger counts are written in the syntax accepted by tracefs.
- Histogram variable tracking starts fresh for each tracing instance.
- Paused histograms keep their paused state when restored.

The base includes the trigger-filter and underscore fixes you picked up.
The new sed expression also uses POSIX syntax, following your feedback.

I tested each fix and the full series in temporary tracefs instances on
my Ubuntu machine, running kernel 7.0.0-38-generic, with recording
disabled. The patch emails include the individual reproduction details.
The fixture checks also cover each step of the series.

Feedback is welcome.

Thanks,
Eduardo

Eduardo Mucelli Rezende Oliveira (4):
  tools/bootconfig: Quote event filters in ftrace2bconf.sh
  tools/bootconfig: Export replayable event trigger counts
  tools/bootconfig: Reset histogram variable tracking for each instance
  tools/bootconfig: Preserve paused histograms in ftrace2bconf.sh

 tools/bootconfig/scripts/ftrace2bconf.sh | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)


base-commit: 1dc6d173c43e10a1d0ee36b43d0d2f371f4d262a
-- 
2.53.0

[PATCH 1/4] tools/bootconfig: Quote event filters in ftrace2bconf.sh

[Eduardo Mucelli Rezende Oliveira]

ftrace2bconf.sh emits event filters without enclosing bootconfig quotes.
A filter such as prev_comm == "a,b" is therefore parsed as an array,
while a # truncates the value and a semicolon or closing brace can make
the exported configuration invalid.

Quote filters containing bootconfig delimiters so that the complete
expression remains one value. Choose the enclosing quote in the same
way as the bootconfig utility. Leave filters without delimiters as they
are, including expressions that contain both kinds of quote.

Fixes: 2b86062a34a8 ("tools/bootconfig: Add a script to generates bootconfig from ftrace")
Signed-off-by: Eduardo Mucelli Rezende Oliveira <edumucelli@gmail.com>
---
I tested event filters containing a comma, semicolon, # and closing
brace in a temporary tracefs instance on my Ubuntu machine, running
kernel 7.0.0-38-generic, with recording disabled.

The original export split or truncated these filters, or produced a
config that could not be parsed. With the fix, each expression remained
one value and was restored unchanged. A filter containing an ordinary
space worked in both versions.

 tools/bootconfig/scripts/ftrace2bconf.sh | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/bootconfig/scripts/ftrace2bconf.sh b/tools/bootconfig/scripts/ftrace2bconf.sh
index b01297217cf3..8c5889d0420c 100755
--- a/tools/bootconfig/scripts/ftrace2bconf.sh
+++ b/tools/bootconfig/scripts/ftrace2bconf.sh
@@ -126,6 +126,14 @@ per_event_options() { # event-dir
 	fi
 	val=`cat $evdir/filter`
 	if [ "$val" != "none" ]; then
+		case "$val" in
+		*[',;#}']*)
+			case "$val" in
+			*\"*) val="'$val'";;
+			*) val="\"$val\"";;
+			esac
+			;;
+		esac
 		emit_kv $PREFIX.event.$group.$event.filter = "$val"
 	fi
 }
-- 
2.53.0

[PATCH 2/4] tools/bootconfig: Export replayable event trigger counts

[Eduardo Mucelli Rezende Oliveira]

Tracefs displays generic event trigger counts as :unlimited or :count=N.
ftrace2bconf.sh copies these annotations into the exported action, but
the trigger input syntax requires an omitted count or :N. Replaying an
exported traceoff or enable_event action therefore fails.

Remove :unlimited and convert :count=N to :N in the command token before
emitting the action. Keep the filter text unchanged and leave histogram
commands alone, where count can be a variable name.

Fixes: 2b86062a34a8 ("tools/bootconfig: Add a script to generates bootconfig from ftrace")
Signed-off-by: Eduardo Mucelli Rezende Oliveira <edumucelli@gmail.com>
---
I tested traceoff with an unlimited count, traceoff:7 with a filter,
and enable_event with a finite count and filter in a temporary tracefs
instance on my Ubuntu machine, running kernel 7.0.0-38-generic, with
recording disabled.

The original exported count annotations were rejected during replay.
With the fix, the triggers and their filters were restored correctly.
A histogram defining a variable named count also worked unchanged.

 tools/bootconfig/scripts/ftrace2bconf.sh | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/bootconfig/scripts/ftrace2bconf.sh b/tools/bootconfig/scripts/ftrace2bconf.sh
index 8c5889d0420c..82c4fe021fb7 100755
--- a/tools/bootconfig/scripts/ftrace2bconf.sh
+++ b/tools/bootconfig/scripts/ftrace2bconf.sh
@@ -118,6 +118,15 @@ per_event_options() { # event-dir
 	grep -v "^#" $evdir/trigger |
 		sed -e 's/ \[active\]$//' -e 's/ \[paused\]$//' |
 		while IFS= read -r action; do
+		action_cmd=${action%% *}
+		action_rest=${action#"$action_cmd"}
+		case "$action_cmd" in
+		hist:*) ;;
+		*:unlimited)
+			action="${action_cmd%:unlimited}$action_rest";;
+		*:count=*)
+			action="${action_cmd%:count=*}:${action_cmd##*:count=}$action_rest";;
+		esac
 		emit_kv $PREFIX.event.$group.$event.actions += "'$action'"
 	done
 
-- 
2.53.0

[PATCH 3/4] tools/bootconfig: Reset histogram variable tracking for each instance

[Eduardo Mucelli Rezende Oliveira]

Histogram variables are scoped to a trace instance, but ftrace2bconf.sh
keeps DEFINED_VARS across calls to event_options(). If an earlier instance
has defined ts0, a later instance can export a consumer of its own ts0
before exporting that instance's provider. Replaying the configuration
then fails because the local variable has not been defined yet.

Initialize the variable resolver state when starting each instance so
that its consumers are deferred until their local providers are exported.

Fixes: 2b86062a34a8 ("tools/bootconfig: Add a script to generates bootconfig from ftrace")
Signed-off-by: Eduardo Mucelli Rezende Oliveira <edumucelli@gmail.com>
---
I reproduced this with two temporary tracefs instances on my Ubuntu
machine, running kernel 7.0.0-38-generic, with recording disabled. Both
instances defined a histogram variable with the same name. In the second
instance, a consumer sorted before its local provider.

The original exporter put that consumer first and replay failed with an
undefined variable. With the fix, the local provider was exported first
and all three histograms were restored correctly.

 tools/bootconfig/scripts/ftrace2bconf.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/bootconfig/scripts/ftrace2bconf.sh b/tools/bootconfig/scripts/ftrace2bconf.sh
index 82c4fe021fb7..6d36219eb997 100755
--- a/tools/bootconfig/scripts/ftrace2bconf.sh
+++ b/tools/bootconfig/scripts/ftrace2bconf.sh
@@ -84,8 +84,6 @@ synth_event_options() {
 }
 
 # Variables resolver
-DEFINED_VARS=
-UNRESOLVED_EVENTS=
 
 defined_vars() { # event-dir
 	grep "^hist" $1/trigger | grep -o ':[a-zA-Z0-9_]*='
@@ -159,6 +157,8 @@ retry_unresolved() {
 
 event_options() {
 	# PREFIX and INSTANCE must be set
+	DEFINED_VARS=
+	UNRESOLVED_EVENTS=
 	if [ $PREFIX = "ftrace" ]; then
 		# define the dynamic events
 		kprobe_event_options
-- 
2.53.0

[PATCH 4/4] tools/bootconfig: Preserve paused histograms in ftrace2bconf.sh

[Eduardo Mucelli Rezende Oliveira]

The trigger file reports a paused histogram with a trailing [paused]
annotation. Removing that annotation without adding a pause parameter
exports the histogram as an active trigger. Replaying the exported
configuration therefore enables aggregation that was previously paused.

Add the pause parameter after the hist prefix before removing the display
annotation. This keeps the parameter before any filter expression and
preserves both the paused state and the filter.

Fixes: 2b86062a34a8 ("tools/bootconfig: Add a script to generates bootconfig from ftrace")
Signed-off-by: Eduardo Mucelli Rezende Oliveira <edumucelli@gmail.com>
---
I tested paused histograms with and without a filter, plus an active
histogram, in a temporary tracefs instance on my Ubuntu machine, running
kernel 7.0.0-38-generic, with recording disabled.

The original exporter restored the paused histograms as active. With
the fix, both paused histograms kept their state and filters, and the
active histogram still restored as active. One filter contained the
literal string [paused], which was preserved as well.

 tools/bootconfig/scripts/ftrace2bconf.sh | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/bootconfig/scripts/ftrace2bconf.sh b/tools/bootconfig/scripts/ftrace2bconf.sh
index 6d36219eb997..93879181dab9 100755
--- a/tools/bootconfig/scripts/ftrace2bconf.sh
+++ b/tools/bootconfig/scripts/ftrace2bconf.sh
@@ -114,7 +114,8 @@ per_event_options() { # event-dir
 		DEFINED_VARS="$DEFINED_VARS "`defined_vars $evdir`
 	fi
 	grep -v "^#" $evdir/trigger |
-		sed -e 's/ \[active\]$//' -e 's/ \[paused\]$//' |
+		sed -e '/^hist:.* \[paused\]$/s/^hist:/hist:pause:/' \
+			-e 's/ \[active\]$//' -e 's/ \[paused\]$//' |
 		while IFS= read -r action; do
 		action_cmd=${action%% *}
 		action_rest=${action#"$action_cmd"}
-- 
2.53.0