From patchwork Mon May 1 15:08:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13227565 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35757C77B73 for ; Mon, 1 May 2023 15:08:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231728AbjEAPIw (ORCPT ); Mon, 1 May 2023 11:08:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232231AbjEAPIv (ORCPT ); Mon, 1 May 2023 11:08:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7EC710C4; Mon, 1 May 2023 08:08:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 409B461D94; Mon, 1 May 2023 15:08:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16B86C433EF; Mon, 1 May 2023 15:08:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1682953728; bh=yy/VRMw6a0z+Y3rWWDFPZXl5xhnE27mdtMQd62YK4ck=; h=From:To:Cc:Subject:Date:From; b=caZb1UYa+5N3BPAUd8QrhR55YVqq3iP8fiXzSR0U/K0UqNK4sejoq30QIyeScb2li e0CIqCmxjUrxeoC+LunyAZYLKw2JGjrpdSOK16kQCaOROYm1XLVGBZf/qwn60KHjqM OJ4ywt94U2OgZnJ43ndecN5M5ywPex2eXR3oeSUFgPZ8k5zIQyzxaPPem2WmOCLbif N9dTxPLH8nbLwUWJJ4nHLgjeKoDgMXyMxBRhEBQtDk7tDyvYIH7Ih7BYBQeUKVKqbX lBBmhksFMBgLqtcR/B1QqzfcptHmWYjB8prrEAO/s6dNLCmNkllfSq/mO2ja5LtsBQ kQzWPmGh2vejg== From: "Masami Hiramatsu (Google)" To: linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Steven Rostedt , mhiramat@kernel.org, Florent Revest , Mark Rutland , Will Deacon , Mathieu Desnoyers , Martin KaFai Lau , bpf@vger.kernel.org Subject: [PATCH v9 00/11] tracing: Add fprobe events Date: Tue, 2 May 2023 00:08:45 +0900 Message-ID: <168295372484.3157983.731333785390494141.stgit@mhiramat.roam.corp.google.com> X-Mailer: git-send-email 2.40.1.495.gc816e09b53d-goog User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Hi, Here is the 8th version of improve fprobe and add a basic fprobe event support for ftrace (tracefs) and perf. Here is the previous version. https://lore.kernel.org/all/168255826500.2565678.17719875734305974633.stgit@mhiramat.roam.corp.google.com/ This version is a minor update for fixing wrong indentation [8/11] and update kconfig help message[6/11]. You can also get this series from: git://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git topic/fprobe-event-ext With this fprobe events, we can continue to trace function entry/exit even if the CONFIG_KPROBES_ON_FTRACE is not available. Since CONFIG_KPROBES_ON_FTRACE requires the CONFIG_DYNAMIC_FTRACE_WITH_REGS, it is not available if the architecture only supports CONFIG_DYNAMIC_FTRACE_WITH_ARGS (e.g. arm64). And that means kprobe events can not probe function entry/exit effectively on such architecture. But this problem can be solved if the dynamic events supports fprobe events because fprobe events doesn't use kprobe but ftrace via fprobe. FPROBE EVENTS ============= Fprobe events allows user to add new events on the entry and exit of kernel functions (which can be ftraced). Unlike kprobe events, the fprobe events can only probe the function entry and exit, and it can only trace the function args, return value, and stacks. (no registers) For probing function body, users can continue to use the kprobe events. The tracepoint probe events (tprobe events) also allows user to add new events dynamically on the tracepoint. Most of the tracepoint already has trace-events, so this feature is useful if you only want to know a specific parameter, or trace the tracepoints which has no trace-events (e.g. sched_*_tp tracepoints only exposes the tracepoints.) The fprobe events syntax is; f[:[GRP/][EVENT]] FUNCTION [FETCHARGS] f[MAXACTIVE][:[GRP/][EVENT]] FUNCTION%return [FETCHARGS] And tracepoint probe events syntax is; t[:[GRP/][EVENT]] TRACEPOINT [FETCHARGS] This series includes BTF argument support for fprobe/tracepoint events, and kprobe events. This allows us to fetch a specific function parameter by name, and all parameters by '$$args'. Note that enabling this feature, you need to enable CONFIG_BPF_SYSCALL and confirm that your arch supports CONFIG_HAVE_FUNCTION_ARG_ACCESS_API. E.g. # echo 't kfree ptr' >> dynamic_events # echo 'f kfree object' >> dynamic_events # cat dynamic_events t:tracepoints/kfree kfree ptr=ptr f:fprobes/kfree__entry kfree object=object # echo 1 > events/fprobes/enable # echo 1 > events/tracepoints/enable # echo > trace # head -n 20 trace | tail # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | tail-84 [000] ..... 1324.561958: kfree__entry: (kfree+0x4/0x140) object=0xffff888006383c00 tail-84 [000] ...1. 1324.561961: kfree: (__probestub_kfree+0x4/0x10) ptr=0xffff888006383c00 tail-84 [000] ..... 1324.561988: kfree__entry: (kfree+0x4/0x140) object=0x0 tail-84 [000] ...1. 1324.561988: kfree: (__probestub_kfree+0x4/0x10) ptr=0x0 tail-84 [000] ..... 1324.561989: kfree__entry: (kfree+0x4/0x140) object=0xffff88800671e600 tail-84 [000] ...1. 1324.561989: kfree: (__probestub_kfree+0x4/0x10) ptr=0xffff88800671e600 tail-84 [000] ..... 1324.562368: kfree__entry: (kfree+0x4/0x140) object=0xffff8880065e0580 tail-84 [000] ...1. 1324.562369: kfree: (__probestub_kfree+0x4/0x10) ptr=0xffff8880065e0580 Thank you, --- Masami Hiramatsu (Google) (11): fprobe: Pass return address to the handlers tracing/probes: Add fprobe events for tracing function entry and exit. selftests/ftrace: Add fprobe related testcases tracing/probes: Add tracepoint support on fprobe_events tracing/probes: Move event parameter fetching code to common parser tracing/probes: Support function parameters if BTF is available tracing/probes: Add $$args meta argument for all function args tracing/probes: Add BTF retval type support selftests/ftrace: Add tracepoint probe test case selftests/ftrace: Add BTF arguments test cases Documentation: tracing/probes: Add fprobe event tracing document Documentation/trace/fprobetrace.rst | 187 +++ Documentation/trace/index.rst | 1 include/linux/fprobe.h | 11 include/linux/rethook.h | 2 include/linux/trace_events.h | 3 include/linux/tracepoint-defs.h | 1 include/linux/tracepoint.h | 5 kernel/kprobes.c | 1 kernel/trace/Kconfig | 26 kernel/trace/Makefile | 1 kernel/trace/bpf_trace.c | 6 kernel/trace/fprobe.c | 17 kernel/trace/rethook.c | 3 kernel/trace/trace.c | 13 kernel/trace/trace.h | 11 kernel/trace/trace_eprobe.c | 44 - kernel/trace/trace_fprobe.c | 1194 ++++++++++++++++++++ kernel/trace/trace_kprobe.c | 33 - kernel/trace/trace_probe.c | 504 +++++++- kernel/trace/trace_probe.h | 43 + kernel/trace/trace_uprobe.c | 8 lib/test_fprobe.c | 10 samples/fprobe/fprobe_example.c | 6 .../ftrace/test.d/dynevent/add_remove_btfarg.tc | 54 + .../ftrace/test.d/dynevent/add_remove_fprobe.tc | 26 .../ftrace/test.d/dynevent/add_remove_tprobe.tc | 27 .../ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 99 ++ .../ftrace/test.d/dynevent/tprobe_syntax_errors.tc | 82 + .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 13 29 files changed, 2291 insertions(+), 140 deletions(-) create mode 100644 Documentation/trace/fprobetrace.rst create mode 100644 kernel/trace/trace_fprobe.c create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe.tc create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_tprobe.tc create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc -- Masami Hiramatsu (Google)