From patchwork Mon Dec 19 09:33:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Donglin Peng X-Patchwork-Id: 13076390 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 DD8FBC4332F for ; Mon, 19 Dec 2022 09:33:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231179AbiLSJde (ORCPT ); Mon, 19 Dec 2022 04:33:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbiLSJde (ORCPT ); Mon, 19 Dec 2022 04:33:34 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11CF1BC2E; Mon, 19 Dec 2022 01:33:33 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id 82so5818372pgc.0; Mon, 19 Dec 2022 01:33:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=OggAim5Je4Yr+Sjs36owBqPiq8ydpoA77qdczuzrMkM=; b=FV3K8ucwlRrw4GcHArasd5fp2D9aKclTs4mZ62ANobgl/SB6zSlc78ylzPwmJdXwsz m2sFpYfU0PivR6c5FyN2pz0obhkbfUQMYKlLZ/forzoEgL77ar541/nSGVioBqBAGS/5 LO+E6VFtxyzLKKF3B0PcCiyYfUbKpnUQA32ZEeqWCmSS8Ct35gN6j2dl2Eef1CtOU/+d vGjcJaP2cy7T1FdcA8gYFHHElo6jtXYdETsuChYf30kzEo8eHaP1P8DGPdUM1oMfqXOP l/v2drVdqEEs8qdNERQqV1wOIv96qg+lW4YQPxCcUGOjZj8qWLTX1k0X/YjNh4PY8d4r fztw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=OggAim5Je4Yr+Sjs36owBqPiq8ydpoA77qdczuzrMkM=; b=UXpyk5JDjUz/c7fChfkLCjY3t0qAloZuiIEis5C0WrznfgX99hAUA+4VKtWk93urCJ BwPGUgwiVElNLUZFElTBFeA+Hlw48iGSn27ufl8mJazNHIdSGEzHLLts4A9P5Vo/3peq Ck1KwwTlq982y4a9S4TnfZUjS/Ewqs8NkChezWABKrzCnaCQ8xEDTDk8ctDKULXWkdd9 YsPc08kI6LOx0s/HS40JdiWDpUTkaymSb+fzS2A+IUKB+vPKj72/zzIZl3oWHJVHWj7i SizL3s9pkMUlLTKIPmviqhLUf7zi5CuhcmO1RYRjY3llHW1S31OPOJCm7VxMq3AyGknr oVrQ== X-Gm-Message-State: AFqh2kpv4XGot3tdb0/Ey0kYkw8d6G4cjQj5xlYx+l9BJ1b59xu0TpDT oyKPPnZtQBLAFYBOIYHONoI= X-Google-Smtp-Source: AMrXdXtH2jx0kgtNnzVwwruLH/rviESTbVzBie1OnaNCvdNPhDj5w20aC8G85KWtKOOg+CwGCCGfJQ== X-Received: by 2002:a62:31c3:0:b0:574:c62c:2f55 with SMTP id x186-20020a6231c3000000b00574c62c2f55mr7309502pfx.3.1671442412507; Mon, 19 Dec 2022 01:33:32 -0800 (PST) Received: from ubuntu.localdomain ([60.221.148.50]) by smtp.gmail.com with ESMTPSA id q3-20020aa78423000000b00576d76c9927sm6126485pfn.106.2022.12.19.01.33.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Dec 2022 01:33:31 -0800 (PST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org Cc: xiehuan09@gmail.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Donglin Peng , kernel test robot Subject: [PATCH v5] tracing/probe: add a char type to show the character value of traced arguments Date: Mon, 19 Dec 2022 01:33:24 -0800 Message-Id: <20221219093324.227861-1-dolinux.peng@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org There are scenes that we want to show the character value of traced arguments other than a decimal or hexadecimal or string value for debug convinience. I add a new type named 'char' to do it and a new test case file named 'kprobe_args_char.tc' to do selftest for char type. For example: The to be traced function is 'void demo_func(char type, char *name);', we can add a kprobe event as follows to show argument values as we want: echo 'p:myprobe demo_func $arg1:char +0($arg2):char[5]' > kprobe_events we will get the following trace log: ... myprobe: (demo_func+0x0/0x29) arg1='A' arg2={'b','p','f','1',''} Signed-off-by: Donglin Peng Acked-by: Masami Hiramatsu (Google) Reported-by: kernel test robot --- Changes in v5: - wrap the output character with single quotes  - add a test case named kprobe_args_char.tc to do selftest Changes in v4:  - update the example in the commit log Changes in v3:  - update readme_msg Changes in v2:  - fix build warnings reported by kernel test robot  - modify commit log --- Documentation/trace/kprobetrace.rst | 3 +- kernel/trace/trace.c | 2 +- kernel/trace/trace_probe.c | 2 + kernel/trace/trace_probe.h | 1 + .../ftrace/test.d/kprobe/kprobe_args_char.tc | 47 +++++++++++++++++++ 5 files changed, 53 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst index 4274cc6a2f94..007972a3c5c4 100644 --- a/Documentation/trace/kprobetrace.rst +++ b/Documentation/trace/kprobetrace.rst @@ -58,7 +58,7 @@ Synopsis of kprobe_events 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), hexadecimal types - (x8/x16/x32/x64), "string", "ustring" and bitfield + (x8/x16/x32/x64), "char", "string", "ustring" and bitfield are supported. (\*1) only for the probe on function entry (offs == 0). @@ -80,6 +80,7 @@ E.g. 'x16[4]' means an array of x16 (2bytes hex) with 4 elements. Note that the array can be applied to memory type fetchargs, you can not apply it to registers/stack-entries etc. (for example, '$stack1:x8[8]' is wrong, but '+8($stack):x8[8]' is OK.) +Char type can be used to show the character value of traced arguments. 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. "ustring" type is an alternative of string for user-space. diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6d7ef130f57e..c602081e64c8 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5615,7 +5615,7 @@ static const char readme_msg[] = "\t $stack, $stack, $retval, $comm,\n" #endif "\t +|-[u](), \\imm-value, \\\"imm-string\"\n" - "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n" + "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n" "\t b@/, ustring,\n" "\t \\[\\]\n" #ifdef CONFIG_HIST_TRIGGERS diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index bb2f95d7175c..ae8d479e94aa 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -50,6 +50,7 @@ DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x") DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x") DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x") DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx") +DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "\'%c\'") int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent) { @@ -93,6 +94,7 @@ static const struct fetch_type probe_fetch_types[] = { ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), + ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0), ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0), ASSIGN_FETCH_TYPE_END diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index de38f1c03776..8c86aaa8b0c9 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -164,6 +164,7 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(x16); DECLARE_BASIC_PRINT_TYPE_FUNC(x32); DECLARE_BASIC_PRINT_TYPE_FUNC(x64); +DECLARE_BASIC_PRINT_TYPE_FUNC(char); DECLARE_BASIC_PRINT_TYPE_FUNC(string); DECLARE_BASIC_PRINT_TYPE_FUNC(symbol); diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc new file mode 100644 index 000000000000..285b4770efad --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc @@ -0,0 +1,47 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Kprobe event char type argument +# requires: kprobe_events + +case `uname -m` in +x86_64) + ARG1=%di +;; +i[3456]86) + ARG1=%ax +;; +aarch64) + ARG1=%x0 +;; +arm*) + ARG1=%r0 +;; +ppc64*) + ARG1=%r3 +;; +ppc*) + ARG1=%r3 +;; +s390*) + ARG1=%r2 +;; +mips*) + ARG1=%r4 +;; +*) + echo "Please implement other architecture here" + exit_untested +esac + +: "Test get argument (1)" +echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):char" > kprobe_events +echo 1 > events/kprobes/testprobe/enable +echo "p:test $FUNCTION_FORK" >> kprobe_events +grep -qe "testprobe.* arg1='t'" trace + +echo 0 > events/kprobes/testprobe/enable +: "Test get argument (2)" +echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):char arg2=+0(${ARG1}):char[4]" > kprobe_events +echo 1 > events/kprobes/testprobe/enable +echo "p:test $FUNCTION_FORK" >> kprobe_events +grep -qe "testprobe.* arg1='t' arg2={'t','e','s','t'}" trace