From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: "yebin (H)" <yebin10@huawei.com>
Cc: <rostedt@goodmis.org>, <mathieu.desnoyers@efficios.com>,
<linux-trace-kernel@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 3/7] tracing/probes: support '%pd' type for print struct dentry's name
Date: Wed, 24 Jan 2024 21:27:38 +0900 [thread overview]
Message-ID: <20240124212738.04b1beee70ccf5b5148b2ac8@kernel.org> (raw)
In-Reply-To: <65B079F2.4000802@huawei.com>
On Wed, 24 Jan 2024 10:46:10 +0800
"yebin (H)" <yebin10@huawei.com> wrote:
>
>
> On 2024/1/23 22:40, Masami Hiramatsu (Google) wrote:
> > On Tue, 23 Jan 2024 17:21:35 +0800
> > Ye Bin <yebin10@huawei.com> wrote:
> >
> >> Similar to '%pd' for printk, use '%pd' for print struct dentry's name.
> >>
> >> Signed-off-by: Ye Bin <yebin10@huawei.com>
> >> ---
> >> kernel/trace/trace_kprobe.c | 6 ++++++
> >> kernel/trace/trace_probe.h | 1 +
> >> 2 files changed, 7 insertions(+)
> >>
> >> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> >> index c4c6e0e0068b..00b74530fbad 100644
> >> --- a/kernel/trace/trace_kprobe.c
> >> +++ b/kernel/trace/trace_kprobe.c
> >> @@ -779,6 +779,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
> >> char buf[MAX_EVENT_NAME_LEN];
> >> char gbuf[MAX_EVENT_NAME_LEN];
> >> char abuf[MAX_BTF_ARGS_LEN];
> >> + char dbuf[MAX_DENTRY_ARGS_LEN];
> > Hmm, no, I don't like to expand stack anymore. Please allocate it
> > from heap.
> Do I need to change the other buffers on the stacks to allocate memory
> from heap?
No, that is not needed for this series, but if you want, you can :)
> >> struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
> >>
> >> switch (argv[0][0]) {
> >> @@ -930,6 +931,11 @@ static int __trace_kprobe_create(int argc, const char *argv[])
> >> argv = new_argv;
> >> }
> >>
> >> + ret = traceprobe_expand_dentry_args(argc, argv, dbuf,
> >> + MAX_DENTRY_ARGS_LEN);
> >> + if (ret)
> >> + goto out;
> > And calling this here will not cover the trace_fprobe.
> >
> > Could you call this from traceprobe_expand_meta_args() instead of
> > calling it directly from trace_kprobe? Then it can be used from
> > fprobe_event too.
> >
> > Thank you,
> At first I wanted to implement the extension logic in
> traceprobe_expand_meta_args(),
> but I found that the code was difficult to understand when I started
> writing.
Yeah, I also found that is a bit different usage.
> If fprobe_event
> wants to support this function, is traceprobe_expand_dentry_args() also
> called?
Yes, it is for expanding '$arg*' into '$arg1 $arg2 ...'
> Or re-encapsulate
> an interface to include the logic of different extensions. In this way,
> the same buffer is used for
> the entire extension process, and the extension function needs to return
> the information about
> the length of the buffer.
OK, I confirmed that will be too much complicated. Then can you just call
it from where the traceprobe_expand_meta_args() is called, which is
__trace_fprobe_create()@trace_fprobe.c ?
But those should be simplified later.
Thank you,
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2024-01-24 12:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-23 9:21 [PATCH v4 0/7] support '%pd' and '%pD' for print file name Ye Bin
2024-01-23 9:21 ` [PATCH v4 1/7] string.h: add str_has_suffix() helper for test string ends with specify string Ye Bin
2024-01-23 9:21 ` [PATCH v4 2/7] tracing/probes: add traceprobe_expand_dentry_args() helper Ye Bin
2024-01-23 14:26 ` Masami Hiramatsu
2024-01-23 9:21 ` [PATCH v4 3/7] tracing/probes: support '%pd' type for print struct dentry's name Ye Bin
2024-01-23 14:40 ` Masami Hiramatsu
2024-01-24 2:46 ` yebin (H)
2024-01-24 12:27 ` Masami Hiramatsu [this message]
2024-01-23 9:21 ` [PATCH v4 4/7] tracing/probes: support '%pD' type for print struct file's name Ye Bin
2024-01-23 9:21 ` [PATCH v4 5/7] tracing: add new type "%pd/%pD" in readme_msg[] Ye Bin
2024-01-23 9:21 ` [PATCH v4 6/7] Documentation: tracing: add new type '%pd' and '%pD' for kprobe Ye Bin
2024-01-23 13:07 ` Masami Hiramatsu
2024-01-23 9:21 ` [PATCH v4 7/7] selftests/ftrace: add test cases for VFS type "%pd" and "%pD" Ye Bin
2024-01-24 1:32 ` Masami Hiramatsu
2024-01-24 1:53 ` yebin (H)
2024-01-24 3:21 ` yebin (H)
2024-01-24 23:30 ` Masami Hiramatsu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240124212738.04b1beee70ccf5b5148b2ac8@kernel.org \
--to=mhiramat@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=rostedt@goodmis.org \
--cc=yebin10@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).