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

From: Masami Hiramatsu
Date: Sun Jan 05 2014 - 20:16:41 EST


(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@xxxxxxxxxxxxxxx>

Looks good for me :)

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

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@xxxxxxxxxxx


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