Patch "tracing: Do not let synth_events block other dyn_event systems during create" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tracing: Do not let synth_events block other dyn_event systems during create

to the 5.15-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-do-not-let-synth_events-block-other-dyn_even.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 9c608dfc3f117e01e7f09aac60f58fb724c40c3b
Author: Beau Belgrave <beaub@xxxxxxxxxxxxxxxxxxx>
Date:   Thu Sep 30 15:38:21 2021 -0700

    tracing: Do not let synth_events block other dyn_event systems during create
    
    [ Upstream commit 4f67cca70c0f615e9cfe6ac42244f3416ec60877 ]
    
    synth_events is returning -EINVAL if the dyn_event create command does
    not contain ' \t'. This prevents other systems from getting called back.
    synth_events needs to return -ECANCELED in these cases when the command
    is not targeting the synth_event system.
    
    Link: https://lore.kernel.org/linux-trace-devel/20210930223821.11025-1-beaub@xxxxxxxxxxxxxxxxxxx
    
    Fixes: c9e759b1e8456 ("tracing: Rework synthetic event command parsing")
    Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
    Signed-off-by: Beau Belgrave <beaub@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 22db3ce95e74f..8c26092db8dee 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -2053,6 +2053,13 @@ static int create_synth_event(const char *raw_command)
 
 	last_cmd_set(raw_command);
 
+	name = raw_command;
+
+	/* Don't try to process if not our system */
+	if (name[0] != 's' || name[1] != ':')
+		return -ECANCELED;
+	name += 2;
+
 	p = strpbrk(raw_command, " \t");
 	if (!p) {
 		synth_err(SYNTH_ERR_INVALID_CMD, 0);
@@ -2061,12 +2068,6 @@ static int create_synth_event(const char *raw_command)
 
 	fields = skip_spaces(p);
 
-	name = raw_command;
-
-	if (name[0] != 's' || name[1] != ':')
-		return -ECANCELED;
-	name += 2;
-
 	/* This interface accepts group name prefix */
 	if (strchr(name, '/')) {
 		len = str_has_prefix(name, SYNTH_SYSTEM "/");