[PATCH] tracing/kprobes: Add trace event trigger invocations

[PATCH] tracing/kprobes: Add trace event trigger invocations

[Tom Zanussi]

Add code to the kprobe/kretprobe event functions that will invoke any
event triggers associated with a probe's ftrace_event_file.

The code to do this is very similar to the invocation code already
used to invoke the triggers associated with static events and
essentially replaces the existing soft-disable checks with a superset
that preserves the original behavior but adds the bits needed to
support event triggers.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 kernel/trace/trace_kprobe.c | 42 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index dae9541..1ee13eb 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -812,12 +812,20 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
 	struct ring_buffer *buffer;
 	int size, dsize, pc;
 	unsigned long irq_flags;
+	unsigned long eflags;
+	enum event_trigger_type __tt = ETT_NONE;
 	struct ftrace_event_call *call = &tp->call;
 
 	WARN_ON(call != ftrace_file->event_call);
 
-	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
-		return;
+	eflags = ftrace_file->flags;
+
+	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
+		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
+			event_triggers_call(ftrace_file, NULL);
+		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
+			return;
+	}
 
 	local_save_flags(irq_flags);
 	pc = preempt_count();
@@ -835,9 +843,16 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
 	entry->ip = (unsigned long)tp->rp.kp.addr;
 	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
 
-	if (!filter_check_discard(ftrace_file, entry, buffer, event))
+	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
+		__tt = event_triggers_call(ftrace_file, entry);
+
+	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
+		ring_buffer_discard_commit(buffer, event);
+	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
 		trace_buffer_unlock_commit_regs(buffer, event,
 						irq_flags, pc, regs);
+	if (__tt)
+		event_triggers_post_call(ftrace_file, __tt);
 }
 
 static __kprobes void
@@ -860,12 +875,20 @@ __kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
 	struct ring_buffer *buffer;
 	int size, pc, dsize;
 	unsigned long irq_flags;
+	unsigned long eflags;
+	enum event_trigger_type __tt = ETT_NONE;
 	struct ftrace_event_call *call = &tp->call;
 
 	WARN_ON(call != ftrace_file->event_call);
 
-	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
-		return;
+	eflags = ftrace_file->flags;
+
+	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
+		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
+			event_triggers_call(ftrace_file, NULL);
+		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
+			return;
+	}
 
 	local_save_flags(irq_flags);
 	pc = preempt_count();
@@ -884,9 +907,16 @@ __kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
 	entry->ret_ip = (unsigned long)ri->ret_addr;
 	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
 
-	if (!filter_check_discard(ftrace_file, entry, buffer, event))
+	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
+		__tt = event_triggers_call(ftrace_file, entry);
+
+	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
+		ring_buffer_discard_commit(buffer, event);
+	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
 		trace_buffer_unlock_commit_regs(buffer, event,
 						irq_flags, pc, regs);
+	if (__tt)
+		event_triggers_post_call(ftrace_file, __tt);
 }
 
 static __kprobes void
-- 
1.8.3.1

Re: [PATCH] tracing/kprobes: Add trace event trigger invocations

[Masami Hiramatsu]

(2013/12/29 11:24), Tom Zanussi wrote:
> Add code to the kprobe/kretprobe event functions that will invoke any
> event triggers associated with a probe's ftrace_event_file.
> 
> The code to do this is very similar to the invocation code already
> used to invoke the triggers associated with static events and
> essentially replaces the existing soft-disable checks with a superset
> that preserves the original behavior but adds the bits needed to
> support event triggers.
> 
> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>

Looks good for me :)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thank you!

> ---
>  kernel/trace/trace_kprobe.c | 42 ++++++++++++++++++++++++++++++++++++------
>  1 file changed, 36 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index dae9541..1ee13eb 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -812,12 +812,20 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
>  	struct ring_buffer *buffer;
>  	int size, dsize, pc;
>  	unsigned long irq_flags;
> +	unsigned long eflags;
> +	enum event_trigger_type __tt = ETT_NONE;
>  	struct ftrace_event_call *call = &tp->call;
>  
>  	WARN_ON(call != ftrace_file->event_call);
>  
> -	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> -		return;
> +	eflags = ftrace_file->flags;
> +
> +	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
> +		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
> +			event_triggers_call(ftrace_file, NULL);
> +		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
> +			return;
> +	}
>  
>  	local_save_flags(irq_flags);
>  	pc = preempt_count();
> @@ -835,9 +843,16 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
>  	entry->ip = (unsigned long)tp->rp.kp.addr;
>  	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
>  
> -	if (!filter_check_discard(ftrace_file, entry, buffer, event))
> +	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
> +		__tt = event_triggers_call(ftrace_file, entry);
> +
> +	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> +		ring_buffer_discard_commit(buffer, event);
> +	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
>  		trace_buffer_unlock_commit_regs(buffer, event,
>  						irq_flags, pc, regs);
> +	if (__tt)
> +		event_triggers_post_call(ftrace_file, __tt);
>  }
>  
>  static __kprobes void
> @@ -860,12 +875,20 @@ __kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
>  	struct ring_buffer *buffer;
>  	int size, pc, dsize;
>  	unsigned long irq_flags;
> +	unsigned long eflags;
> +	enum event_trigger_type __tt = ETT_NONE;
>  	struct ftrace_event_call *call = &tp->call;
>  
>  	WARN_ON(call != ftrace_file->event_call);
>  
> -	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> -		return;
> +	eflags = ftrace_file->flags;
> +
> +	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
> +		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
> +			event_triggers_call(ftrace_file, NULL);
> +		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
> +			return;
> +	}
>  
>  	local_save_flags(irq_flags);
>  	pc = preempt_count();
> @@ -884,9 +907,16 @@ __kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
>  	entry->ret_ip = (unsigned long)ri->ret_addr;
>  	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
>  
> -	if (!filter_check_discard(ftrace_file, entry, buffer, event))
> +	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
> +		__tt = event_triggers_call(ftrace_file, entry);
> +
> +	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> +		ring_buffer_discard_commit(buffer, event);
> +	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
>  		trace_buffer_unlock_commit_regs(buffer, event,
>  						irq_flags, pc, regs);
> +	if (__tt)
> +		event_triggers_post_call(ftrace_file, __tt);
>  }
>  
>  static __kprobes void
> 


-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

Re: [PATCH] tracing/kprobes: Add trace event trigger invocations

[Steven Rostedt]

On Sat, 28 Dec 2013 20:24:08 -0600
Tom Zanussi <tom.zanussi@linux.intel.com> wrote:

> Add code to the kprobe/kretprobe event functions that will invoke any
> event triggers associated with a probe's ftrace_event_file.
> 
> The code to do this is very similar to the invocation code already
> used to invoke the triggers associated with static events and
> essentially replaces the existing soft-disable checks with a superset
> that preserves the original behavior but adds the bits needed to
> support event triggers.
> 
> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> ---
>  kernel/trace/trace_kprobe.c | 42 ++++++++++++++++++++++++++++++++++++------
>  1 file changed, 36 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index dae9541..1ee13eb 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -812,12 +812,20 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
>  	struct ring_buffer *buffer;
>  	int size, dsize, pc;
>  	unsigned long irq_flags;
> +	unsigned long eflags;
> +	enum event_trigger_type __tt = ETT_NONE;

What's the significance of the "__" in the variable?

Looks as if you copied it from the ftrace_raw_event_* macro. The "__"
there is usually recommended because it is a macro and we try to avoid
namespace collisions by adding the "__".

This is a proper function, please remove the "__" from it.

Thanks,

-- Steve


>  	struct ftrace_event_call *call = &tp->call;
>  
>  	WARN_ON(call != ftrace_file->event_call);
>  
> -	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> -		return;
> +	eflags = ftrace_file->flags;
> +
> +	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
> +		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
> +			event_triggers_call(ftrace_file, NULL);
> +		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
> +			return;
> +	}
>  
>  	local_save_flags(irq_flags);
>  	pc = preempt_count();

Re: [PATCH] tracing/kprobes: Add trace event trigger invocations

[Tom Zanussi]

On Mon, 2014-01-06 at 11:10 -0500, Steven Rostedt wrote:
> On Sat, 28 Dec 2013 20:24:08 -0600
> Tom Zanussi <tom.zanussi@linux.intel.com> wrote:
> 
> > Add code to the kprobe/kretprobe event functions that will invoke any
> > event triggers associated with a probe's ftrace_event_file.
> > 
> > The code to do this is very similar to the invocation code already
> > used to invoke the triggers associated with static events and
> > essentially replaces the existing soft-disable checks with a superset
> > that preserves the original behavior but adds the bits needed to
> > support event triggers.
> > 
> > Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> > ---
> >  kernel/trace/trace_kprobe.c | 42 ++++++++++++++++++++++++++++++++++++------
> >  1 file changed, 36 insertions(+), 6 deletions(-)
> > 
> > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> > index dae9541..1ee13eb 100644
> > --- a/kernel/trace/trace_kprobe.c
> > +++ b/kernel/trace/trace_kprobe.c
> > @@ -812,12 +812,20 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
> >  	struct ring_buffer *buffer;
> >  	int size, dsize, pc;
> >  	unsigned long irq_flags;
> > +	unsigned long eflags;
> > +	enum event_trigger_type __tt = ETT_NONE;
> 
> What's the significance of the "__" in the variable?
> 
> Looks as if you copied it from the ftrace_raw_event_* macro. The "__"
> there is usually recommended because it is a macro and we try to avoid
> namespace collisions by adding the "__".
> 
> This is a proper function, please remove the "__" from it.
> 

Right, it was just for consistency with the other invocations.  Updates
to this and the syscall invocations which also do the same thing, coming
up...

Tom

> Thanks,
> 
> -- Steve
> 
> 
> >  	struct ftrace_event_call *call = &tp->call;
> >  
> >  	WARN_ON(call != ftrace_file->event_call);
> >  
> > -	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> > -		return;
> > +	eflags = ftrace_file->flags;
> > +
> > +	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
> > +		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
> > +			event_triggers_call(ftrace_file, NULL);
> > +		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
> > +			return;
> > +	}
> >  
> >  	local_save_flags(irq_flags);
> >  	pc = preempt_count();