From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@redhat.com>,
Alan Maguire <alan.maguire@oracle.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Sven Schnelle <svens@linux.ibm.com>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH] tracing: BTF testing for kprobe-events
Date: Thu, 23 Sep 2021 21:39:43 +0900 [thread overview]
Message-ID: <163240078318.34105.12819521680435948398.stgit@devnote2> (raw)
Hi Steve,
Here I share my testing patch of the BTF for kprobe events.
Currently this only allow user to specify '$$args' for
tracing all arguments of the function. This is only
avaialbe if
- the probe point is on the function entry
- the kernel is compiled with BTF (CONFIG_DEBUG_INFO_BTF)
- the kernel is enables BPF (CONFIG_BPF_SYSCALL)
And Special thanks to Sven! Most of BTF handling part of
this patch comes from his patch [1]
[1] https://stackframe.org/0001-ftrace-arg-hack.patch
What I thought while coding this were;
- kernel/bpf/btf.c can be moved under lib/ so that
the other subsystems can reuse it, independent
from BPF. (Also, this should depends on CONFIG_DEBUG_INFO_BTF)
- some more utility functions can be exposed.
e.g. I copied btf_type_int() from btf.c
- If there are more comments for the BTF APIs, it will
be more useful...
- Overall, the BTF is easy to understand for who
already understand DWARF. Great work!
- I think I need 'ptr' and 'bool' types for fetcharg types.
Anyway, this is just for testing. I have to add some
more cleanup, features and documentations, etc.
Thank you,
---
Masami Hiramatsu (1):
tracing/kprobe: Support $$args for function entry
kernel/trace/trace_kprobe.c | 60 ++++++++++++++++++++++++-
kernel/trace/trace_probe.c | 105 +++++++++++++++++++++++++++++++++++++++++++
kernel/trace/trace_probe.h | 5 ++
3 files changed, 168 insertions(+), 2 deletions(-)
--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>
next reply other threads:[~2021-09-23 12:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 12:39 Masami Hiramatsu [this message]
2021-09-23 12:39 ` [RFC PATCH] tracing/kprobe: Support $$args for function entry Masami Hiramatsu
2021-09-24 17:51 ` Alan Maguire
2021-09-25 14:15 ` Masami Hiramatsu
2021-10-11 22:23 ` [RFC PATCH] tracing: BTF testing for kprobe-events Steven Rostedt
2021-10-13 12:52 ` Masami Hiramatsu
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