This is a note to let you know that I've just added the patch titled
tracing: Simplify creation and deletion of synthetic events
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-simplify-creation-and-deletion-of-synthetic-events.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable+bounces-43478-greg=kroah.com@xxxxxxxxxxxxxxx Thu May 9 04:30:13 2024
From: George Guo <dongtai.guo@xxxxxxxxx>
Date: Thu, 9 May 2024 10:29:19 +0800
Subject: tracing: Simplify creation and deletion of synthetic events
To: gregkh@xxxxxxxxxxxxxxxxxxx, rostedt@xxxxxxxxxxx, mhiramat@xxxxxxxxxx, tom.zanussi@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx, George Guo <guodongtai@xxxxxxxxxx>
Message-ID: <20240509022931.3513365-2-dongtai.guo@xxxxxxxxx>
From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
commit faacb361f271be4baf2d807e2eeaba87e059225f upstream.
Since the event_mutex and synth_event_mutex ordering issue
is gone, we can skip existing event check when adding or
deleting events, and some redundant code in error path.
This changes release_all_synth_events() to abort the process
when it hits any error and returns the error code. It succeeds
only if it has no error.
Link: http://lkml.kernel.org/r/154140847194.17322.17960275728005067803.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Tested-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: George Guo <guodongtai@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace_events_hist.c | 53 +++++++++++++--------------------------
1 file changed, 18 insertions(+), 35 deletions(-)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1028,18 +1028,6 @@ struct hist_var_data {
struct hist_trigger_data *hist_data;
};
-static void add_or_delete_synth_event(struct synth_event *event, int delete)
-{
- if (delete)
- free_synth_event(event);
- else {
- if (!find_synth_event(event->name))
- list_add(&event->list, &synth_event_list);
- else
- free_synth_event(event);
- }
-}
-
static int create_synth_event(int argc, char **argv)
{
struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
@@ -1072,15 +1060,16 @@ static int create_synth_event(int argc,
if (event) {
if (delete_event) {
if (event->ref) {
- event = NULL;
ret = -EBUSY;
goto out;
}
- list_del(&event->list);
- goto out;
- }
- event = NULL;
- ret = -EEXIST;
+ ret = unregister_synth_event(event);
+ if (!ret) {
+ list_del(&event->list);
+ free_synth_event(event);
+ }
+ } else
+ ret = -EEXIST;
goto out;
} else if (delete_event) {
ret = -ENOENT;
@@ -1120,29 +1109,21 @@ static int create_synth_event(int argc,
event = NULL;
goto err;
}
+ ret = register_synth_event(event);
+ if (!ret)
+ list_add(&event->list, &synth_event_list);
+ else
+ free_synth_event(event);
out:
- if (event) {
- if (delete_event) {
- ret = unregister_synth_event(event);
- add_or_delete_synth_event(event, !ret);
- } else {
- ret = register_synth_event(event);
- add_or_delete_synth_event(event, ret);
- }
- }
mutex_unlock(&synth_event_mutex);
mutex_unlock(&event_mutex);
return ret;
err:
- mutex_unlock(&synth_event_mutex);
- mutex_unlock(&event_mutex);
-
for (i = 0; i < n_fields; i++)
free_synth_field(fields[i]);
- free_synth_event(event);
- return ret;
+ goto out;
}
static int release_all_synth_events(void)
@@ -1161,10 +1142,12 @@ static int release_all_synth_events(void
}
list_for_each_entry_safe(event, e, &synth_event_list, list) {
- list_del(&event->list);
-
ret = unregister_synth_event(event);
- add_or_delete_synth_event(event, !ret);
+ if (!ret) {
+ list_del(&event->list);
+ free_synth_event(event);
+ } else
+ break;
}
mutex_unlock(&synth_event_mutex);
mutex_unlock(&event_mutex);
Patches currently in stable-queue which might be from kroah.com@xxxxxxxxxxxxxxx are
queue-4.19/tracing-consolidate-trace_add-remove_event_call-back-to-the-nolock-functions.patch
queue-4.19/tracing-split-up-onmatch-action-data.patch
queue-4.19/tracing-remove-unnecessary-var_ref-destroy-in-track_data_destroy.patch
queue-4.19/tracing-use-str_has_prefix-helper-for-histogram-code.patch
queue-4.19/tracing-simplify-creation-and-deletion-of-synthetic-events.patch
queue-4.19/tracing-refactor-hist-trigger-action-code.patch
queue-4.19/string.h-add-str_has_prefix-helper-function.patch
queue-4.19/tracing-remove-unneeded-synth_event_mutex.patch
queue-4.19/tracing-add-unified-dynamic-event-framework.patch
queue-4.19/tracing-use-dyn_event-framework-for-synthetic-events.patch
queue-4.19/tracing-use-str_has_prefix-instead-of-using-fixed-sizes.patch
queue-4.19/tracing-generalize-hist-trigger-onmax-and-save-action.patch
queue-4.19/tracing-have-the-historgram-use-the-result-of-str_has_prefix-for-len-of-prefix.patch
