From: Masami Hiramatsu <mhiramat@kernel.org>
To: Omar Sandoval <osandov@osandov.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Namhyung Kim <namhyung@gmail.com>,
linux-kernel@vger.kernel.org, kernel-team@fb.com,
Omar Sandoval <osandov@fb.com>
Subject: Re: [PATCH v2 1/3] tracing: document "string_size" [ku]probe type
Date: Tue, 7 Jun 2016 15:29:11 +0900 [thread overview]
Message-ID: <20160607152911.976e1c922ae334f8b8675c86@kernel.org> (raw)
In-Reply-To: <afa35ca13fd30802d0d307a71570f8fc46e919a4.1464916142.git.osandov@fb.com>
On Thu, 2 Jun 2016 18:11:01 -0700
Omar Sandoval <osandov@osandov.com> wrote:
> From: Omar Sandoval <osandov@fb.com>
>
> It has been undocumented since it was introduced in commit e09c8614b329
> ("tracing/kprobes: Support "string" type").
Ah, actually, string_size is a support fetch function for string.
So please ignore it. Or would you have any idea to use it?
Thank you,
>
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
> Documentation/trace/kprobetrace.txt | 11 ++++++-----
> Documentation/trace/uprobetracer.txt | 9 +++++----
> 2 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
> index d68ea5fc812b..4b3f5293b7bf 100644
> --- a/Documentation/trace/kprobetrace.txt
> +++ b/Documentation/trace/kprobetrace.txt
> @@ -43,8 +43,8 @@ Synopsis of kprobe_events
> +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
> NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
> FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
> - (u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield
> - are supported.
> + (u8/u16/u32/u64/s8/s16/s32/s64), "string", "string_size", and
> + bitfield are supported.
>
> (*) only for return probe.
> (**) this is useful for fetching a field of data structures.
> @@ -54,9 +54,10 @@ Types
> Several types are supported for fetch-args. Kprobe tracer will access memory
> by given type. Prefix 's' and 'u' means those types are signed and unsigned
> respectively. Traced arguments are shown in decimal (signed) or hex (unsigned).
> -String type is a special type, which fetches a "null-terminated" string from
> -kernel space. This means it will fail and store NULL if the string container
> -has been paged out.
> +"string" is a special type which fetches a null-terminated string from kernel
> +space. This means it will fail and store NULL if the string container has been
> +paged out. "string_size" is the length of a null-terminated string including
> +the NUL byte.
> Bitfield is another special type, which takes 3 parameters, bit-width, bit-
> offset, and container-size (usually 32). The syntax is;
>
> diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt
> index f1cf9a34ad9d..7e0480263c2f 100644
> --- a/Documentation/trace/uprobetracer.txt
> +++ b/Documentation/trace/uprobetracer.txt
> @@ -39,8 +39,8 @@ Synopsis of uprobe_tracer
> +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
> NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
> FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
> - (u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield
> - are supported.
> + (u8/u16/u32/u64/s8/s16/s32/s64), "string",
> + "string_size", and bitfield are supported.
>
> (*) only for return probe.
> (**) this is useful for fetching a field of data structures.
> @@ -50,8 +50,9 @@ Types
> Several types are supported for fetch-args. Uprobe tracer will access memory
> by given type. Prefix 's' and 'u' means those types are signed and unsigned
> respectively. Traced arguments are shown in decimal (signed) or hex (unsigned).
> -String type is a special type, which fetches a "null-terminated" string from
> -user space.
> +"string" is a special type which fetches a null-terminated string from user
> +space. "string_size" is the length of a null-terminated string including the
> +NUL byte.
> Bitfield is another special type, which takes 3 parameters, bit-width, bit-
> offset, and container-size (usually 32). The syntax is;
>
> --
> 2.8.3
>
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2016-06-07 6:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-03 1:11 [PATCH v2 0/3] tracing: expose current->comm to [ku]probe events Omar Sandoval
2016-06-03 1:11 ` [PATCH v2 1/3] tracing: document "string_size" [ku]probe type Omar Sandoval
2016-06-07 6:29 ` Masami Hiramatsu [this message]
2016-06-03 1:11 ` [PATCH v2 2/3] tracing: expose current->comm to [ku]probe events Omar Sandoval
2016-06-07 7:24 ` Masami Hiramatsu
2016-06-07 13:40 ` Namhyung Kim
2016-06-03 1:11 ` [PATCH v2 3/3] tracing: make "string" the default type for [ku]probe event $comm Omar Sandoval
2016-06-07 8:02 ` Masami Hiramatsu
2016-06-07 13:41 ` Namhyung Kim
2016-06-08 13:43 ` Steven Rostedt
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