From nobody Thu Sep 18 00:14:01 2025 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 5E1BDC4332F for ; Wed, 14 Dec 2022 02:53:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237249AbiLNCxe (ORCPT ); Tue, 13 Dec 2022 21:53:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237099AbiLNCw7 (ORCPT ); Tue, 13 Dec 2022 21:52:59 -0500 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22F3065CE for ; Tue, 13 Dec 2022 18:52:43 -0800 (PST) Received: by mail-pl1-x631.google.com with SMTP id t2so1968191ply.2 for ; Tue, 13 Dec 2022 18:52:43 -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=XcHaJrtlRfUwYPTK4kJLL2u6ZuEblPsEK62crrbzYPI=; b=N2dHZ9eAI2dH7pfB/08LBYO7pUpwpDW4Wy142jTM4YqjtM2E3y8UEZ0G2+HQFOb7/5 5jwoh+re26kk5KXPPX56Mu9hd+gihHltN66R7uOzcvDHueMFyKGUXDHMaIadXO9UsLMd mmrlUlOoUKm/T1fBypIojBpuqo57SCXJmRCCLpEuWpOVZM8ahdmn9et5dQMhAKjFs/g/ nTMtvqr5ko2iZN6RphOa7zezvz8H6bYxwhQ+Dz7OhOU5dCSadoRxD84Ex+dnrBFYndhJ Eqesy0ZMoRAal2PXvo5pC/8hVoXaTkkNs8BPvyuHENzemvslOOJinbv5x4xyvdvqOjC4 Eitg== 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=XcHaJrtlRfUwYPTK4kJLL2u6ZuEblPsEK62crrbzYPI=; b=oqKBxlG/q1pF2UOMjIyyyBnAc+CTkRKn5W0QYDfZ49s9M2q+U7WMN/++pLSDzYgvw+ LAcmX9dIr4eUdC3UPGEB5ZvYFoRIm07utGBuW4RIdAp8Rqki1eIQokLG6JQWPBhDMkNH O7WB8YLlZzMobvPTyKsNmlW44YcdqtE2TBeHLZCxZzLR7So3/Ym6FH94a5A4hUxvRkag 7OrgOyiZhWqk2VagS16qx1LZhTz184sQVnQIok9MVBG/+oOMj2jzVp+WiVvb4HYbw82H BsAi4e0VKGB7ZjPjSWaYSlebDEPZDdB70TdDy++a+M8Ecc7rNPeKUu+wjGKrXCA3WDRb fx+w== X-Gm-Message-State: ANoB5pmS7TlN58Q5KUmM5Mminpj+N1WajmR5iTS+Uht7DgyIQLoEhyaG UBPujzqBsLDL4g/HgWmj3hU= X-Google-Smtp-Source: AA0mqf6ms57T/CgfmMaEmP+WW0cCtQKATxKqSxQFbMTAKJgl/wkIyJVcKx8wHTHGLRTQYOFNW6heSg== X-Received: by 2002:a05:6a21:9212:b0:9f:2dd1:c2bc with SMTP id tl18-20020a056a21921200b0009f2dd1c2bcmr27401857pzb.49.1670986363493; Tue, 13 Dec 2022 18:52:43 -0800 (PST) Received: from ubuntu.localdomain ([118.73.12.140]) by smtp.gmail.com with ESMTPSA id r19-20020a63d913000000b00478e7f87f3bsm7304690pgg.67.2022.12.13.18.52.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Dec 2022 18:52:42 -0800 (PST) From: Donglin Peng To: rostedt@goodmis.org Cc: mhiramat@kernel.org, xiehuan09@gmail.com, linux-kernel@vger.kernel.org, Donglin Peng , kernel test robot Subject: [PATCH v2] tracing/probe: add a char type to print the character value of traced arguments Date: Tue, 13 Dec 2022 18:52:18 -0800 Message-Id: <20221214025218.8737-1-dolinux.peng@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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. Add a new type named 'char' to do it. For example: echo 'p:myprobe xxxx +0($arg1):char' > kprobe_events echo 'p:myprobe xxxx +0($arg1):char[2]' > kprobe_events Signed-off-by: Donglin Peng Reported-by: kernel test robot Acked-by: Masami Hiramatsu (Google) --- Changes in v2: - fix build warnings reported by kernel test robot - modify commit log --- Documentation/trace/kprobetrace.rst | 3 ++- kernel/trace/trace_probe.c | 2 ++ kernel/trace/trace_probe.h | 1 + 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kpro= betrace.rst index 4274cc6a2f94..007972a3c5c4 100644 --- a/Documentation/trace/kprobetrace.rst +++ b/Documentation/trace/kprobetrace.rst @@ -58,7 +58,7 @@ Synopsis of kprobe_events NAME=3DFETCHARG : 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. =20 (\*1) only for the probe on function entry (offs =3D=3D 0). @@ -80,6 +80,7 @@ E.g. 'x16[4]' means an array of x16 (2bytes hex) with 4 e= lements. 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 fr= om kernel space. This means it will fail and store NULL if the string contain= er has been paged out. "ustring" type is an alternative of string for user-sp= ace. diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 36dff277de46..a4abf7f6c295 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") =20 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *en= t) { @@ -93,6 +94,7 @@ static const struct fetch_type probe_fetch_types[] =3D { 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), =20 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); =20 +DECLARE_BASIC_PRINT_TYPE_FUNC(char); DECLARE_BASIC_PRINT_TYPE_FUNC(string); DECLARE_BASIC_PRINT_TYPE_FUNC(symbol); =20 --=20 2.25.1