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* [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure
@ 2018-07-25 14:20 Artem Savkov
  2018-07-25 14:30 ` Steven Rostedt
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Artem Savkov @ 2018-07-25 14:20 UTC (permalink / raw)
  To: Steven Rostedt, Masami Hiramatsu
  Cc: Ingo Molnar, linux-kernel, Josh Poimboeuf, Artem Savkov

If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe
it returns an error, but does not unset the tp flags it set previously.
This results in a probe being considered enabled and failures like being
unable to remove the probe through kprobe_events file since probes_open()
expects every probe to be disabled.

Signed-off-by: Artem Savkov <asavkov@redhat.com>
---
 kernel/trace/trace_kprobe.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 21f718472942..27ace4513c43 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -400,11 +400,10 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
 static int
 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 {
+	struct event_file_link *link;
 	int ret = 0;
 
 	if (file) {
-		struct event_file_link *link;
-
 		link = kmalloc(sizeof(*link), GFP_KERNEL);
 		if (!link) {
 			ret = -ENOMEM;
@@ -424,6 +423,16 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 		else
 			ret = enable_kprobe(&tk->rp.kp);
 	}
+
+	if (ret) {
+		if (file) {
+			list_del_rcu(&link->list);
+			kfree(link);
+			tk->tp.flags &= ~TP_FLAG_TRACE;
+		} else {
+			tk->tp.flags &= ~TP_FLAG_PROFILE;
+		}
+	}
  out:
 	return ret;
 }
-- 
2.13.6


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure
  2018-07-25 14:20 [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure Artem Savkov
@ 2018-07-25 14:30 ` Steven Rostedt
  2018-07-25 15:35 ` Josh Poimboeuf
  2018-07-25 15:41 ` Masami Hiramatsu
  2 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2018-07-25 14:30 UTC (permalink / raw)
  To: Masami Hiramatsu; +Cc: Artem Savkov, Ingo Molnar, linux-kernel, Josh Poimboeuf

On Wed, 25 Jul 2018 16:20:38 +0200
Artem Savkov <asavkov@redhat.com> wrote:

> If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe
> it returns an error, but does not unset the tp flags it set previously.
> This results in a probe being considered enabled and failures like being
> unable to remove the probe through kprobe_events file since probes_open()
> expects every probe to be disabled.
> 
> Signed-off-by: Artem Savkov <asavkov@redhat.com>

Masami,

Can you ack this?

Thanks!

-- Steve

> ---
>  kernel/trace/trace_kprobe.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 21f718472942..27ace4513c43 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -400,11 +400,10 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
>  static int
>  enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
>  {
> +	struct event_file_link *link;
>  	int ret = 0;
>  
>  	if (file) {
> -		struct event_file_link *link;
> -
>  		link = kmalloc(sizeof(*link), GFP_KERNEL);
>  		if (!link) {
>  			ret = -ENOMEM;
> @@ -424,6 +423,16 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
>  		else
>  			ret = enable_kprobe(&tk->rp.kp);
>  	}
> +
> +	if (ret) {
> +		if (file) {
> +			list_del_rcu(&link->list);
> +			kfree(link);
> +			tk->tp.flags &= ~TP_FLAG_TRACE;
> +		} else {
> +			tk->tp.flags &= ~TP_FLAG_PROFILE;
> +		}
> +	}
>   out:
>  	return ret;
>  }


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure
  2018-07-25 14:20 [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure Artem Savkov
  2018-07-25 14:30 ` Steven Rostedt
@ 2018-07-25 15:35 ` Josh Poimboeuf
  2018-07-25 15:43   ` Steven Rostedt
  2018-07-25 15:41 ` Masami Hiramatsu
  2 siblings, 1 reply; 6+ messages in thread
From: Josh Poimboeuf @ 2018-07-25 15:35 UTC (permalink / raw)
  To: Artem Savkov; +Cc: Steven Rostedt, Masami Hiramatsu, Ingo Molnar, linux-kernel

On Wed, Jul 25, 2018 at 04:20:38PM +0200, Artem Savkov wrote:
> If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe
> it returns an error, but does not unset the tp flags it set previously.
> This results in a probe being considered enabled and failures like being
> unable to remove the probe through kprobe_events file since probes_open()
> expects every probe to be disabled.
> 
> Signed-off-by: Artem Savkov <asavkov@redhat.com>

Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>

-- 
Josh

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure
  2018-07-25 14:20 [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure Artem Savkov
  2018-07-25 14:30 ` Steven Rostedt
  2018-07-25 15:35 ` Josh Poimboeuf
@ 2018-07-25 15:41 ` Masami Hiramatsu
  2018-07-25 15:42   ` Steven Rostedt
  2 siblings, 1 reply; 6+ messages in thread
From: Masami Hiramatsu @ 2018-07-25 15:41 UTC (permalink / raw)
  To: Artem Savkov; +Cc: Steven Rostedt, Ingo Molnar, linux-kernel, Josh Poimboeuf

On Wed, 25 Jul 2018 16:20:38 +0200
Artem Savkov <asavkov@redhat.com> wrote:

> If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe
> it returns an error, but does not unset the tp flags it set previously.
> This results in a probe being considered enabled and failures like being
> unable to remove the probe through kprobe_events file since probes_open()
> expects every probe to be disabled.
> 

Looks good to me.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thanks!

> Signed-off-by: Artem Savkov <asavkov@redhat.com>
> ---
>  kernel/trace/trace_kprobe.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 21f718472942..27ace4513c43 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -400,11 +400,10 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
>  static int
>  enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
>  {
> +	struct event_file_link *link;
>  	int ret = 0;
>  
>  	if (file) {
> -		struct event_file_link *link;
> -
>  		link = kmalloc(sizeof(*link), GFP_KERNEL);
>  		if (!link) {
>  			ret = -ENOMEM;
> @@ -424,6 +423,16 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
>  		else
>  			ret = enable_kprobe(&tk->rp.kp);
>  	}
> +
> +	if (ret) {
> +		if (file) {
> +			list_del_rcu(&link->list);
> +			kfree(link);
> +			tk->tp.flags &= ~TP_FLAG_TRACE;
> +		} else {
> +			tk->tp.flags &= ~TP_FLAG_PROFILE;
> +		}
> +	}
>   out:
>  	return ret;
>  }
> -- 
> 2.13.6
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure
  2018-07-25 15:41 ` Masami Hiramatsu
@ 2018-07-25 15:42   ` Steven Rostedt
  0 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2018-07-25 15:42 UTC (permalink / raw)
  To: Masami Hiramatsu; +Cc: Artem Savkov, Ingo Molnar, linux-kernel, Josh Poimboeuf

On Thu, 26 Jul 2018 00:41:13 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> On Wed, 25 Jul 2018 16:20:38 +0200
> Artem Savkov <asavkov@redhat.com> wrote:
> 
> > If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe
> > it returns an error, but does not unset the tp flags it set previously.
> > This results in a probe being considered enabled and failures like being
> > unable to remove the probe through kprobe_events file since probes_open()
> > expects every probe to be disabled.
> >   
> 
> Looks good to me.
> 
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thanks Masami,

-- Steve


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure
  2018-07-25 15:35 ` Josh Poimboeuf
@ 2018-07-25 15:43   ` Steven Rostedt
  0 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2018-07-25 15:43 UTC (permalink / raw)
  To: Josh Poimboeuf; +Cc: Artem Savkov, Masami Hiramatsu, Ingo Molnar, linux-kernel

On Wed, 25 Jul 2018 10:35:57 -0500
Josh Poimboeuf <jpoimboe@redhat.com> wrote:

> On Wed, Jul 25, 2018 at 04:20:38PM +0200, Artem Savkov wrote:
> > If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe
> > it returns an error, but does not unset the tp flags it set previously.
> > This results in a probe being considered enabled and failures like being
> > unable to remove the probe through kprobe_events file since probes_open()
> > expects every probe to be disabled.
> > 
> > Signed-off-by: Artem Savkov <asavkov@redhat.com>  
> 
> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
> 

Thanks Josh!

Queued up and currently being tested.

-- Steve

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, back to index

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-07-25 14:20 [PATCH v2] tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure Artem Savkov
2018-07-25 14:30 ` Steven Rostedt
2018-07-25 15:35 ` Josh Poimboeuf
2018-07-25 15:43   ` Steven Rostedt
2018-07-25 15:41 ` Masami Hiramatsu
2018-07-25 15:42   ` Steven Rostedt

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