[PATCH 0/2] tracing: Fix config dependency and trigger parser

[PATCH 0/2] tracing: Fix config dependency and trigger parser

[Masami Hiramatsu]

Hi,

These are some fixes which I found recentry on ftrace.

 - Since the boot-time tracing synthetic event feature is decoupled
   from trigger recenty, it should use CONFIG_SYNTH_EVENT.
 - The parser of event trigger seems rejecting some redundant
   spaces. But it is hard users to find the wrong point. Such
   spaces should be accepted.

BTW, I also found the trigger parser accepts some inputs which
may not correctly formatted, e.g.

 # echo "traceon 1" > events/ftrace/print/trigger

(from the document, it must be "traceon:1")
But I think this does not decrease the usability.

Thank you,

---

Masami Hiramatsu (2):
      tracing/boot: Fix config dependency for synthedic event
      tracing: Fix event trigger to accept redundant spaces


 kernel/trace/trace_boot.c           |    2 +-
 kernel/trace/trace_events_trigger.c |   21 +++++++++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

[PATCH 1/2] tracing/boot: Fix config dependency for synthedic event

[Masami Hiramatsu]

Since commit 726721a51838 ("tracing: Move synthetic events to
a separate file") decoupled synthetic event from histogram,
boot-time tracing also has to check CONFIG_SYNTH_EVENT instead
of CONFIG_HIST_TRIGGERS.

Fixes: 726721a51838 ("tracing: Move synthetic events to a separate file")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace_boot.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 9de29bb45a27..8b5490cb02bb 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -120,7 +120,7 @@ trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
 }
 #endif
 
-#ifdef CONFIG_HIST_TRIGGERS
+#ifdef CONFIG_SYNTH_EVENTS
 static int __init
 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
 {

[PATCH 2/2] tracing: Fix event trigger to accept redundant spaces

[Masami Hiramatsu]

Fix the event trigger to accept redundant spaces in
the trigger input.

For example, these return -EINVAL

echo " traceon" > events/ftrace/print/trigger
echo "traceon  if common_pid == 0" > events/ftrace/print/trigger
echo "disable_event:kmem:kmalloc " > events/ftrace/print/trigger

But these are hard to find what is wrong.

To fix this issue, use skip_spaces() to remove spaces
in front of actual tokens, and set NULL if there is no
token.

Fixes: 85f2b08268c0 ("tracing: Add basic event trigger framework")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace_events_trigger.c |   21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 3a74736da363..f725802160c0 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -216,11 +216,17 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file)
 
 int trigger_process_regex(struct trace_event_file *file, char *buff)
 {
-	char *command, *next = buff;
+	char *command, *next;
 	struct event_command *p;
 	int ret = -EINVAL;
 
+	next = buff = skip_spaces(buff);
 	command = strsep(&next, ": \t");
+	if (next) {
+		next = skip_spaces(next);
+		if (!*next)
+			next = NULL;
+	}
 	command = (command[0] != '!') ? command : command + 1;
 
 	mutex_lock(&trigger_cmd_mutex);
@@ -630,8 +636,14 @@ event_trigger_callback(struct event_command *cmd_ops,
 	int ret;
 
 	/* separate the trigger from the filter (t:n [if filter]) */
-	if (param && isdigit(param[0]))
+	if (param && isdigit(param[0])) {
 		trigger = strsep(&param, " \t");
+		if (param) {
+			param = skip_spaces(param);
+			if (!*param)
+				param = NULL;
+		}
+	}
 
 	trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 
@@ -1368,6 +1380,11 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
 	trigger = strsep(&param, " \t");
 	if (!trigger)
 		return -EINVAL;
+	if (param) {
+		param = skip_spaces(param);
+		if (!*param)
+			param = NULL;
+	}
 
 	system = strsep(&trigger, ":");
 	if (!trigger)

Re: [PATCH 0/2] tracing: Fix config dependency and trigger parser

[Tom Zanussi]

Hi Masami,

On Sat, 2020-06-20 at 12:45 +0900, Masami Hiramatsu wrote:
> Hi,
> 
> These are some fixes which I found recentry on ftrace.
> 
>  - Since the boot-time tracing synthetic event feature is decoupled
>    from trigger recenty, it should use CONFIG_SYNTH_EVENT.

Oops, yeah, I missed this one in the update, thanks for finding it.

>  - The parser of event trigger seems rejecting some redundant
>    spaces. But it is hard users to find the wrong point. Such
>    spaces should be accepted.
> 

Agreed, your patch makes things much better, thanks.

You can add my reviewed-by for both patches.

Reviewed-by: Tom Zanussi <zanussi@kernel.org>

Thanks,

Tom

> BTW, I also found the trigger parser accepts some inputs which
> may not correctly formatted, e.g.
> 
>  # echo "traceon 1" > events/ftrace/print/trigger
> 
> (from the document, it must be "traceon:1")
> But I think this does not decrease the usability.
> 
> Thank you,
> 
> ---
> 
> Masami Hiramatsu (2):
>       tracing/boot: Fix config dependency for synthedic event
>       tracing: Fix event trigger to accept redundant spaces
> 
> 
>  kernel/trace/trace_boot.c           |    2 +-
>  kernel/trace/trace_events_trigger.c |   21 +++++++++++++++++++--
>  2 files changed, 20 insertions(+), 3 deletions(-)
> 
> --
> Masami Hiramatsu (Linaro) <mhiramat@kernel.org>