2022-10-18 08:09:24

by Song Chen

Subject: [PATCH] trace/kprobe: remove duplicated call of ring_buffer_event_data

Function __kprobe_trace_func calls ring_buffer_event_data to get
a ring buffer, however, it has been done in above call
trace_event_buffer_reserve.

So remove one of them.

Signed-off-by: Song Chen <[email protected]>
---
kernel/trace/trace_kprobe.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 23f7f0ec4f4c..dfd5809a4a65 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1394,7 +1394,6 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
return;

fbuffer.regs = regs;
- entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
entry->ip = (unsigned long)tk->rp.kp.addr;
store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);

--
2.25.1

2022-10-18 14:12:31

by Steven Rostedt

Subject: Re: [PATCH] trace/kprobe: remove duplicated call of ring_buffer_event_data

[ Added Masami who's the new co-maintainer, and this is his code ]

On Tue, 18 Oct 2022 15:13:06 +0800
Song Chen <[email protected]> wrote:

> Function __kprobe_trace_func calls ring_buffer_event_data to get
> a ring buffer, however, it has been done in above call
> trace_event_buffer_reserve.
>
> So remove one of them.
>

May as well add:

Fixes: 5e6cd84e2f8bd ("tracing/kprobes: Do not open code event reserve logic")

Reviewed-by: Steven Rostedt (Google) <[email protected]>

-- Steve


> Signed-off-by: Song Chen <[email protected]>
> ---
> kernel/trace/trace_kprobe.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 23f7f0ec4f4c..dfd5809a4a65 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1394,7 +1394,6 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
> return;
>
> fbuffer.regs = regs;
> - entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
> entry->ip = (unsigned long)tk->rp.kp.addr;
> store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
>

2022-10-18 16:21:26

by Masami Hiramatsu

Subject: Re: [PATCH] trace/kprobe: remove duplicated call of ring_buffer_event_data

Hi,

On Tue, 18 Oct 2022 09:59:32 -0400
Steven Rostedt <[email protected]> wrote:

>
> [ Added Masami who's the new co-maintainer, and this is his code ]
>
> On Tue, 18 Oct 2022 15:13:06 +0800
> Song Chen <[email protected]> wrote:
>
> > Function __kprobe_trace_func calls ring_buffer_event_data to get
> > a ring buffer, however, it has been done in above call
> > trace_event_buffer_reserve.
> >
> > So remove one of them.
> >
>
> May as well add:
>
> Fixes: 5e6cd84e2f8bd ("tracing/kprobes: Do not open code event reserve logic")
>
> Reviewed-by: Steven Rostedt (Google) <[email protected]>

Oops, and we have another line in __kretprobe_trace_func() too.

Song, can you update this patch to fix the __kretprobe_trace_func() too?

Thank you,

>
> -- Steve
>
>
> > Signed-off-by: Song Chen <[email protected]>
> > ---
> > kernel/trace/trace_kprobe.c | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> > index 23f7f0ec4f4c..dfd5809a4a65 100644
> > --- a/kernel/trace/trace_kprobe.c
> > +++ b/kernel/trace/trace_kprobe.c
> > @@ -1394,7 +1394,6 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
> > return;
> >
> > fbuffer.regs = regs;
> > - entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
> > entry->ip = (unsigned long)tk->rp.kp.addr;
> > store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
> >
>


--
Masami Hiramatsu (Google) <[email protected]>

2022-10-19 01:38:49

by Song Chen

Subject: Re: [PATCH] trace/kprobe: remove duplicated call of ring_buffer_event_data

Hi,

在 2022/10/18 23:22, Masami Hiramatsu (Google) 写道:
> Hi,
>
> On Tue, 18 Oct 2022 09:59:32 -0400
> Steven Rostedt <[email protected]> wrote:
>
>>
>> [ Added Masami who's the new co-maintainer, and this is his code ]
>>
>> On Tue, 18 Oct 2022 15:13:06 +0800
>> Song Chen <[email protected]> wrote:
>>
>>> Function __kprobe_trace_func calls ring_buffer_event_data to get
>>> a ring buffer, however, it has been done in above call
>>> trace_event_buffer_reserve.
>>>
>>> So remove one of them.
>>>
>>
>> May as well add:
>>
>> Fixes: 5e6cd84e2f8bd ("tracing/kprobes: Do not open code event reserve logic")
>>
>> Reviewed-by: Steven Rostedt (Google) <[email protected]>
>
> Oops, and we have another line in __kretprobe_trace_func() too.
>
> Song, can you update this patch to fix the __kretprobe_trace_func() too?
>
> Thank you,
>

will do

Song
>>
>> -- Steve
>>
>>
>>> Signed-off-by: Song Chen <[email protected]>
>>> ---
>>> kernel/trace/trace_kprobe.c | 1 -
>>> 1 file changed, 1 deletion(-)
>>>
>>> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
>>> index 23f7f0ec4f4c..dfd5809a4a65 100644
>>> --- a/kernel/trace/trace_kprobe.c
>>> +++ b/kernel/trace/trace_kprobe.c
>>> @@ -1394,7 +1394,6 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
>>> return;
>>>
>>> fbuffer.regs = regs;
>>> - entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
>>> entry->ip = (unsigned long)tk->rp.kp.addr;
>>> store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
>>>
>>
>
>